An Image of the Earth taken from Voyager II as it orbited Saturn
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Aircraft that break the sound barrier are banned over many countries – but could quiet supersonic technology bring them back?
A few months ago we did a few pieces on Super Sonic flight 🛫 Here is a follow up on those posts. Planes that go at hyper speeds that won’t go BOOM!
NASA, though best known for its spacecraft, also has a pretty sizeable fleet of aircraft under its belt. It has a venerable tradition of X-planes, where ‘X’ stands for experimental. It started back in 1946 with the X-1, which became the first aircraft to travel faster than sound. Three-quarters of a century on, its new plane, the X-59, also aims to break the sound barrier – but this time it’s going to do it quietly.
The speed of sound has always caused headaches for aircraft designers. The reason lies in the nature of sound itself. When anything from a handclap to a rocket disturbs the air, it causes pressure changes that spread out like a wave. The speed of this wave depends on the properties of the air, but under normal conditions it’s around 1,200km/h (750mph).
“All aircraft change the pressure in the air around them as they fly,” explains Peter Coen of NASA’s Langley Research Center. The consequences depend on whether the aircraft is flying slower or faster than the sound it produces.
In a typical subsonic aircraft, the pressure changes are gradual, [so] air molecules ahead of the aircraft sense the pressure change before the aircraft reaches them,” Coen continues. “But if an airplane flies faster than sound, the molecules upstream don’t know that it is coming.”
From the point of view of those molecules, all the sound waves the aircraft has been pushing ahead of it arrive at once. “The pressure changes happen instantaneously in what is called a shock wave,” Coen says. “A shock wave, from the nose of the aircraft for example, travels outward in all directions and merges with other shocks, from the wings or cockpit window… The result of this is two large, distinct shock waves that we hear on the ground as the two booms of a sonic boom.”
While we may only hear the sonic boom briefly, it’s actually produced continuously for as long as the aircraft is supersonic. People at different points under the flight path will hear it at different times – and when they do, they’ll all jump out of their skin in surprise. That’s why, back in the 1970s, the United States and many other countries imposed an almost complete ban on supersonic flight over their territories.
In pictures: X-59 QueSST, the supersonic aircraft that doesn’t go boom
This situation is unlikely to change unless the sonic boom is reduced to an acceptable level. This is where Coen and his team come in. He’s the mission integration manager for NASA’s Low-Boom Flight Demonstration project. Their aim is to produce a viable supersonic design that’s no more disruptive to people on the ground than an ordinary aircraft. That would’ve been unthinkable 50 years ago, but advances in computer-aided design mean it’s within our grasp today. The result, a collaborative effort with Lockheed Martin, is the X-59 – a proposed test vehicle dubbed QueSST (for Quiet Supersonic Technology).
“The X-59 aircraft is equipped with unique shaping and supersonic technologies,” Coen explains. “A long slender nose, engine placement on the top of the aircraft and its External Vision System are all designed to control the strength and position of the shock waves to produce a softer sound to those on the ground.”
The aim isn’t to eliminate shock waves altogether – which is impossible – but to design the aircraft in such a way that the shock waves are spaced roughly equally along its length. “Because of this, the shock waves do not merge into the double shock boom but are individually weakened and softened,” says Coen.
Although it was designed with aerodynamic considerations first and foremost, the X-59 is a striking-looking aircraft by any standards. Almost a third of its 30-metre length is taken up by the sharply pointed nose, behind which the single-seat cockpit is so carefully moulded into the streamlined fuselage that it’s barely discernible. In fact, the pilot doesn’t even have a forward-facing windscreen – just an HD video display showing the view ahead (that’s the External Vision System that Coen referred to earlier).
All this careful shaping should, according to the simulations, reduce the dreaded sonic boom to a more acceptable ‘sonic thump’. To quantify sudden, sharp sounds, NASA uses a measure called ‘perceived level decibels’, or PLdB. A conventional sonic boom is around 105PLdB, while a car door slamming six metres away is just 75PLdB. That’s the level the X-59 is aiming at. When it’s flying at 1,400km/h (925mph) – around 1.4 times the speed of sound – at a typical cruising altitude, all you should hear is a mild thump no worse than your neighbour slamming a car door.
So far, however, it’s all theory. Only when NASA takes delivery of the X-59 from Lockheed Martin early in 2023 will they be able to see how reality measures up. The test schedule will fall into two phases – careful scientific measurements over NASA’s California test ranges to start with, followed by a community response study over a few selected US cities.
The latter phase is crucial, because there are subtleties in the way people react to sounds that go beyond measurable quantities like PLdB. Coen and his team hope the X-59’s sonic thump will be acceptable to the public, but they can’t be sure. “Once we get into the community overflight test phase of the mission, we will collect this input from people who are actually on the ground and hear the sound the X-59 makes when it flies overhead,” Coen explains.
Gauging public reaction is critical, because ultimately only this – as opposed to any number of scientific measurements and calculations – will carry weight with aviation regulators. The aim is to persuade them to modify the blanket ban on supersonic overflights, granting an exemption for any future aircraft that might pick up on the X-59’s low-boom design features.
If everything goes the way NASA is hoping, the final years of this decade could see the start of a second great era of supersonic air travel, following the abortive first era that began and ended with Concorde.
The Concorde was operated between 1976 and 2003 by just two airlines, British Airways and Air France. The stringent flight restrictions meant the iconic aircraft was only ever used on transatlantic routes. Concorde was notoriously expensive, of course, but that was largely because it was the first of its kind.
And with such a limited range of available routes, aerospace companies simply didn’t have sufficient incentive to carry out the research that might have made it more economical in terms of fuel consumption and passenger capacity.
In an alternative timeline in which the sonic boom problem never arose, the situation today might have been very different, with supersonic air travel being the norm on all the world’s long-haul routes. Now there’s a real possibility that this could happen in our world, if the X-59 lives up to expectations.
Andrew May is a science, history and sci-fi writer. He studied Natural Sciences at Cambridge University and obtained a PhD in Theoretical Astrophysics from Manchester University. He worked in the scientific civil service, including three years in the Ministry of Defence.
NASA’s Low-Noise Supersonic Plane Has No Front Window. Here’s How They See Through
To be as quiet as it is, the X-59 had to give up forward windows, so NASA developed a vision system instead.
By Loukia Papadopoulos Oct 09, 2021 (Updated: Oct 10, 2021 05:04 EDT)
Supersonic planes might be speedy but they have one distinct problem: They generate an unbearably loud sound. When an aircraft travels faster than the speed of sound, shockwaves form and travel away from the aircraft, merging and generating sonic booms heard on the ground for miles.
The new single-seat plane X-59 will be 99.7 feet long, 29.5 feet wide (30 m by 9 m), and will cruise at an altitude of 55,000 feet (16.7 km) while moving at a speed of Mach 1.4, or 925 mph (1,488 km/h). What it won’t have, however, is a forward-facing window.
According to Forbes, NASA’s XVS subsystem lead, Randy Bailey, calls the artificial vision system “the last line of defense” in the domain where the pilot can use the system to see an oncoming air vehicle. “Way before we get to that point we have ATC [air traffic control] and ADS-B information assuming the other [air traffic] is on it,” he explained.
The X-59 does not include a forward canopy in order to maintain its long needle-nosed shape, Bailey also added. Instead, it uses what Bailey refers to as an “electronic window.”
NASA’s electronic window XVS system includes a pair of high-resolution cameras, and a 4K monitor. The first 4K camera is located atop and slightly ahead of the cockpit and is augmented with synthetic vision capability, allowing the pilot to artificially see through fog and clouds.
A second camera underneath the nose can extend during takeoffs and landings. In this sense, the aircraft is fully covered and does not require a window. NASA’s XVS system provides all the visual information required for a pilot to fly safely.
Galaxies exchange matter with their external environment thanks to galactic winds.
The MUSE instrument from the Very Large Telescope has, for the very first time, mapped the galactic wind that drive these exchanges between galaxies and nebulae.
This observation led to the detection of some of the Universe’s missing matter.
Galaxies can receive and exchange matter with their external environment thanks to the galactic winds created by stellar explosions. Thanks to the MUSE instrument[1] from the Very Large Telescope at the ESO, an international research team, led on the French side by the CNRS and l’Université Claude Bernard Lyon,[1,2] has mapped a galactic wind for the first time. This unique observation, which is detailed in a study published in MNRAS on September 16, 2021, helped to reveal where some of the Universe’s missing matter is located and to observe the formation of a nebula around a galaxy.
Galaxies are like islands of stars in the Universe, and possess ordinary or baryonic matter, which consists of elements from the periodic table, as well as dark matter, whose composition remains unknown. One of the major problems in understanding the formation of galaxies is that approximately 80% of the baryons[3] that make up the normal matter of galaxies is missing. According to models, they were expelled from galaxies into intergalactic space by the galactic winds created by stellar explosions.
Observation of a part of the Universe thanks to MUSE Left: Demarcation of the quasar and the galaxy studied here, Gal1.
Center: Nebula consisting of magnesium represented with a size scale
Right: superimposition of the nebula and the Gal1 galaxy.
An international team,[4] led on the French side by researchers from the CNRS and l’Université Claude Bernard Lyon 1, successfully used the MUSE instrument to generate a detailed map of the galactic wind driving exchanges between a young galaxy in formation and a nebula (a cloud of gas and interstellar dust).
The team chose to observe galaxy Gal1 due to the proximity of a quasar, which served as a “lighthouse” for the scientists by guiding them toward the area of study. They also planned to observe a nebula around this galaxy, although the success of this observation was initially uncertain, as the nebula’s luminosity was unknown.
The perfect positioning of the galaxy and the quasar, as well as the discovery of gas exchange due to galactic winds, made it possible to draw up a unique map. This enabled the first observation of a nebula in formation that is simultaneously emitting and absorbing magnesium—some of the Universe’s missing baryons—with the Gal1 galaxy.
This type of normal matter nebula is known in the near Universe, but their existence for young galaxies in formation had only been supposed.
Scientists thus discovered some of the Universe’s missing baryons, thereby confirming that 80–90% of normal matter is located outside of g
Notes:
1) MUSE, which stands for Multi Unit Spectroscopic Explorer, is a 3D spectrograph designed to explore the distant Universe. The Centre de recherché astrophysique de Lyon (CNRS/Université Claude Bernard-Lyon 1/ENS de Lyon) led its construction.
2) Researchers from the Centre de recherché astrophysique de Lyon (CNRS/Université Claude Bernard Lyon 1/ENS de Lyon), the Galaxies, étoiles, physique, instrumentation laboratory (CNRS/Observatoire de Paris – PSL), and the Institut de recherché en astrophysique et planétologie (CNRS/Université Toulouse III – Paul Sabatier/CNES) participated in the project.
3) Baryons are particles consisting of three quarks, such as protons and neutrons. They make up atoms and molecules as well as all visible structures in the observable Universe (stars, galaxies, galaxy clusters, etc.). The “missing” baryons, which had never before been observed, must be distinguished from dark matter, which consists of non-baryonic matter of an unknown nature.
4) Including scientists from Saint Mary’s University in Canada, the Institute for Astrophysics at the University of Potsdam in Germany, Leiden University in the Netherlands, the University of Geneva and the Swiss Federal Polytechnic School in Zurich, the Inter-University Centre for Astronomy and Astrophysics in India, and the University of Porto in Portugal.
Reference: “MusE GAs FLOw and Wind (MEGAFLOW) VIII. Discovery of a Mgii emission halo probed by a quasar sightline” by Johannes Zabl, Nicolas F Bouché, Lutz Wisotzki, Joop Schaye, Floriane Leclercq, Thibault Garel, Martin Wendt, Ilane Schroetter, Sowgat Muzahid, Sebastiano Cantalupo, Thierry Contini, Roland Bacon, Jarle Brinchmann and Johan Richard, 28 July 2021, Monthly Notices of the Royal Astronomical Society.
By Freda Kreier – is the news intern at Science News. She holds a bachelor’s in molecular biology from Colorado College and a master’s in science communication from the University of California, Santa Cruz.
Schematic diagram of the lunar lander of the Chang’e-5 mission.
Credit: CNSA (China National Space Administration) / CLEP (China Lunar Exploration Program) / GRAS (Ground Research Application System).
Lava oozed across the moon’s surface just 2 billion years ago, bits of lunar rocks retrieved by China’s Chang’e-5 mission reveal.
A chemical analysis of the volcanic rocks confirms that the moon remained volcanically active far longer that its size would suggest possible, researchers report online October 7 in Science.
Chang’e-5 is the first mission to retrieve lunar rocks and return them to Earth in over 40 years (SN: 12/1/20). An international group of researchers found that the rocks formed 2 billion years ago, around when multicellular life first evolved on Earth. That makes them the youngest moon rocks ever collected, says study coauthor Carolyn Crow, a planetary scientist at the University of Colorado Boulder.
The moon formed roughly 4.5 billion years ago. Lunar rocks from the Apollo and Soviet missions of the late 1960s and 70s revealed that volcanism on the moon was commonplace for the first billion or so years of its existence, with flows lasting for millions, if not hundreds of millions, of years.
A capsule containing moon rocks (shown) collected by China’s Chang’e-5 mission landed back on Earth in December 2020.
CHINESE NATIONAL SPACE AGENCY’S LUNAR EXPLORATION AND SPACE ENGINEERING CENTER
Given its size, scientist thought that the moon started cooling off around 3 billion years ago, eventually becoming the quiet, inactive neighbor it is today. Yet a dearth of craters in some regions left scientists scratching their heads. Parts of celestial bodies devoid of volcanism accumulate more and more craters over time, in part because there aren’t lava flows depositing new material that hardens into smooth stretches. The moon’s smoother spots seemed to suggest that volcanism had persisted past the moon’s early history.
“Young volcanism on a small body like the moon is challenging to explain, because usually small bodies cool fast,” says Juliane Gross, a planetary scientist at Rutgers University in Piscataway, N.J., not involved in the study.
Scientist had suggested that radioactive elements might offer an explanation for later volcanism. Radioactive decay generates a lot of heat, which is why nuclear reactors are kept in water. Enough radioactive materials in the moon’s mantle, the layer just below the visible crust, would have provided a heat source that could explain younger lava flows.
To test this theory, the Chang’e-5 lander gathered chunks of basalt — a type of rock that forms from volcanic activity — from a previously unexplored part of the moon thought to be younger than 3 billion years old. The team determined that the rocks formed from lava flows 2 billion years ago, but chemical analysis did not yield the concentration of radioactive elements one would expect if radioactive decay were to explain the volcanism.
The Chang’e-5 lunar lander extracts samples of the moon that were returned to Earth. The lunar material is the first brought back to Earth in more than 40 years.CHINESE NATIONAL SPACE AGENCY’S LUNAR EXPLORATION AND SPACE ENGINEERING CENTER
This finding is compelling scientists to consider what other forces could have maintained volcanic activity on the moon.
One theory, says study coauthor Alexander Nemchin, a planetary scientist at the Beijing SHRIMP Center and Curtin University in Bentley, Australia, is that gravitational forces from the Earth could have liquefied the lunar interior, keeping lunar magma flowing for another billion or so years past when it should have stopped.
“The moon was a lot closer 2 billion years ago,” Nemchin explains. As the moon slowly inched away from the Earth — a slow escape still at work today — these forces would have become less and less powerful until volcanism eventually petered out.
The location of the Chang’e-5 landing site (43.06°N, 51.92°W) and adjacent regions of the Moon, as well as impact craters that were examined as possible sources of exotic fragments among the recently returned lunar materials.
Credit: Qian et al. 2021
Impacts from asteroids and comets also could have kept the moon’s volcanic juices flowing, but “at this point, any guess is a good guess,” says Jessica Barnes, a planetary scientist at the University of Arizona in Tucson not involved in the study.
“This is a good example of why we need to get to know our closest neighbor,” Barnes says. “A lot people think we already know what’s going on with the moon, but it’s actually quite mysterious.”
CITATIONS X. Che et al. Age and composition of young basalts on the moon, measured from samples returned by Chang’e-5. Science. Published online October 7, 2021. doi: 10.1126/science.abl7957.
Explanation: What color is the Moon? It depends on the night.
Outside of the Earth’s atmosphere, the dark Moon, which shines by reflected sunlight, appears a magnificently brown-tinged gray. Viewed from inside the Earth’s atmosphere, though, the moon can appear quite different. The featured image highlights a collection of apparent colors of the full moon documented by one astrophotographer over 10 years from different locations across Italy. A red or yellow colored moon usually indicates a moon seen near the horizon.
There, some of the blue light has been scattered away by a long path through the Earth’s atmosphere, sometimes laden with fine dust. A blue-colored moon is more rare and can indicate a moon seen through an atmosphere carrying larger dust particles.
What created the purple moon is unclear — it may be a combination of several effects. The last image captures the total lunar eclipse of 2018 July — where the moon, in Earth’s shadow, appeared a faint red — due to light refracted through air around the Earth. The next full moon will occur at the end of this month (moon-th) and is known in some cultures as the Beaver Moon.
Even in Eclipse there are different colors to Luna
Each year, our moon moves distinctly, inexorably farther from Earth—just a tiny bit, about an inch and a half, a nearly imperceptible change. There is no stopping this slow ebbing, no way to turn back the clock. The forces of gravity are invisible and unshakable, and no matter what we do or how we feel about them, they will keep nudging the moon along. Over many millions of years, we’ll continue to grow apart.
Given this rather melodramatic description, you might wonder: Don’t you have better things to think about than the moon? Well no, not really, because I’m a space reporter and it’s my job to contemplate celestial bodies and write about them. And also because a representation of this phenomenon recently played out in China during festivities for the Mid-Autumn Festival, which marks the full moon closest to the fall equinox. A giant balloon designed to resemble the moon, craters and all, broke free and rolled into the street. Video footage of the unscripted moment shows two people running after the massive moon as it tumbles away. Bye!
Can I give you the Moon in a bottle?
The moon used to be closer. When it first formed, about 4.5 billion years ago, molded out of rocky debris that had been floating around Earth, the moon orbited 10 times nearer to the planet than it does today. The debris, scientists believe, had come from a collision between Earth and a mysterious Mars-sized object. Fresh out of the cosmic oven, the moon was hot and molten, glowing red in the night sky. Back then, scientists say, the moon was moving away at a rate of about eight inches per year.
Our planet and its moon were always going to grow apart like this. The gravity of moons, small as they are in comparison, can still tug at their planets, causing the larger worlds to bulge outward a little bit. On an ocean-covered planet like ours, the effect shows up in the shifting tides. The moon pulls at our oceans, but those oceans pull back, making the moon speed up in its orbit. And “if you speed up while orbiting Earth, you are escaping Earth more successfully, so you orbit from a farther distance,” James O’Donoghue, a planetary scientist at JAXA, Japan’s space agency, explained to me. Scientists refer to this phenomenon as “lunar retreat”—a delightful term, as I’d prefer to imagine the moon enjoying itself at a relaxing getaway, bending its rocky body into various yoga poses, rather than slowly ghosting Earth.
Scientists have measured this retreat by beaming lasers at mirrors that the Apollo astronauts left on the moon, using that data, along with other sources, to estimate past movements. The rate of lunar retreat has shifted over the years; spikes have coincided with significant events, such as a bombardment of meteors on the moon and fluctuating ice ages on Earth. The constant retreat has influenced Earth beyond the ebb and flow of its tides. The forces that draw the moon away from us are also slowing down the planet’s rotation, stretching out the length of our days. In the beginning, when the moon was cozying up to us and Earth spun faster, a day lasted just four hours. At the current rate of lunar retreat, it would take a century to tack on an extra two milliseconds or so to the length of the day.
The moon is expected to continue drifting this way for the very scientific measure of forever. And, despite the premise of an upcoming action movie called Moonfall, it’s not going to smack into us either. Someday, about 600 million years from now, the moon will orbit far enough away that humankind will lose one of its oldest cosmic sights: total solar eclipses. The moon won’t be able to block the sun’s light and cast its own shadow onto Earth. But the moon will remain bound to Earth, looking out onto a very different, much hotter version of the planet, as oceans start to evaporate. Of course, a few billion years after that, the sun will derail the moon entirely, and Earth too, when it runs out of fuel, expands, and engulfs the inner solar system in a spectacular act of star death.
This weekend, I looked through a telescope for the first time, into a much calmer solar system. (I know, right? Some space reporter I am!) A neighbor had set one up on my building’s roof, and I tried to pay attention as he explained the different lenses and their amplification capacity, but I was too excited, thinking only, Let me see, let me see. I had seen the moon just as a bright two-dimensional orb in the sky, with dark spots that play tricks on our brains, making us see familiar patterns where none exist. People have interpreted these glyphs in many ways: a human face, the silhouette of a rabbit. What has the moon seen in us? “The moon had been observing the earth close-up longer than anyone,” the Japanese writer Haruki Murakami wrote in his novel 1Q84. “It must have witnessed all of the phenomena occurring—and all of the acts carried out—on this earth.” The moon is still watching. What must it be thinking now, after such a horrid year and a half?
The Moon blocks the Sun in a total Eclipse.
My neighbor swiveled his telescope across the cloudless sky. There was Jupiter and its twisty bands, faint but unmistakable, and three tiny points of light just off to the side—its largest moons. There was Saturn, a perfect ball, its rings sticking out at each side. And then there was the moon: covered in craters and cracks and shadows, so richly textured that the skin of my fingertips prickled at the sight, as if I were rolling the moon around in my hand like a marble, feeling its jagged edges. I decided not to spoil the moment for everyone else on the roof that night by telling them that the moon was, slowly but surely, distancing itself from us. The experience of distance—from our families, from a time of relative normalcy—had already tormented many of us enough. Better to focus on the little image in the lens, on seeing the moon properly for the first time. It may be wishing Earth a very long goodbye, but it was nice to say hello.
Space exploration requires all kinds of interesting solutions to complex problems. There is a branch of NASA designed to support the innovators trying to solve those problems – the Institute for Advanced Concepts (NIAC). They occasionally hand out grant funding to worthy projects trying to tackle some of these challenges.
The results from one of those grants are now in, and they are intriguing. A team from Masten Space Systems, supported by Honeybee Robotics, Texas A&M, and the University of Central Florida, came up with a way a lunar lander could deposit its own landing pad on the way down.
Lunar dust poses a significant problem to any powered landers on the surface. The retrograde rockets needed to land on the Moon’s surface softly will also kick dust and rock up into the air, potentially damaging the lander itself or any surrounding human infrastructure.
A landing pad would lessen the impact of this dust and provide a more stable place for the landing itself.
Landing with and without the deposition system. (Masten Space Systems)
But constructing such a landing pad the traditional way would be prohibitively expensive. Current estimates put the cost of building a lunar landing pad using traditional materials at approximately US$120 million.
Any such mission also suffers from a chicken and egg problem. How to get the materials to build the landing pad land in place if there is no landing pad to begin with?
The technology Masten has developed is an ingenious solution to both of those problems.
Depositing a landing pad while descending would allow spacefarers to have a landing pad in place before a spacecraft ever touches down there. It would also cost much less to install as all that is needed is a relatively simple additive to the rocket exhaust already being blasted into the surface.
Masten’s general idea is easy enough to understand.
Adding solid pellets into the rocket exhaust would allow that material to partially liquefy and deposit onto the exhaust’s blast zone, potentially hardening it to a point where dust is no longer a factor as it is encapsulated in a hard external shell. Masten believed it could find the right material to add to rocket exhaust to do exactly that.
Success or failure would come down to the physical properties of the additive pellets. Any additive with too much heat tolerance wouldn’t melt appropriately in the rocket exhaust, essentially bombarding the surface with tiny bullets.
On the other hand, any additive with too little heat tolerance could be completely melted by the rocket exhaust and vaporized into a useless cloud.
To find the perfect balance, Masten developed a two-tiered system, with relatively large (0.5 mm) alumina particles used to create a base layer of 1 mm of melted lunar surface combined with alumina.
Process of the FAST particle injector. (Masten Space Systems)
Then, as the lander got closer to the base layer, the additive would switch to a 0.024 mm alumina particle, which would deposit at 650 m/s onto the base layer and create a 6 m diameter landing pad that would cool in 2.5 seconds.
That all sounds like a pretty impressive idea, but it is still early days. Like many federal grants, the NIAC grant focused on developing this depositable landing pad idea takes a phased approach. Most of the Phase I, which has just been completed, focused on proving the idea is feasible, which Masten believes it is.
Feasible is not the same as functional, but that is precisely what NIAC grants are supposed to support – wild ideas that might just fundamentally change some aspect of space exploration.
If Masten is correct and the approach is possible and can be scaled up, landing pads might be seen cropping up all over the lunar surface. And eventually all over Mars as well.
Since its discovery in 1930, Pluto has been a bit of a puzzle.
For starters, not only is Pluto smaller than any other planet in the solar system, but it’s also smaller than Earth’s moon. It also has an extremely low gravitational pull at only 0.07 times the mass of the objects in its orbit, which is just a fraction of the Moon’s own strength.
At the same time, Pluto’s surface resembles that of terrestrial planets such as Mars, Venus or the Earth, yet its nearest neighbors are the gaseous Jovian planets such as Uranus or Neptune. In fact, Pluto’s orbit is so erratic that it led many scientists to initially believe that it originated elsewhere in space and the Sun’s gravity pulled it in.
These qualities have challenged the scientific view of Pluto’s status as a planet for years. It wasn’t until the discovery of Eris in 2005, one of many increasingly identified trans-Neptunian objects (objects beyond the planet Neptune), that the International Astronomical Union (IAU) defined criteria for classifying planets.
With Eris and other trans-Neptunian objects sharing similar characteristics with Pluto, the definition for dwarf planets was created, and Pluto got downgraded in 2006.
So what are dwarf planets, how do they differ from “true” planets and what are their characteristics?
The History of Dwarf Planets
A dwarf planet is a celestial body that almost meets the definition of a “true” planet. According to the IAU, which sets definitions for planetary science, a planet must:
1) Orbit the Sun.
2) Have enough mass to achieve hydrostatic equilibrium and assume a nearly round shape.
3) Dominate its orbit and not share it with other objects.
Dwarf planets, along with not being moons or satellites, fail to clear the neighborhoods around their orbits. This is the primary reason why Pluto lost its status: because it shares part of its orbit with the Kuiper belt, a dense region of icy space bodies.
Based on this definition, the IAU has recognized five dwarf planets: Pluto, Eris, Makemake, Haumea, and Ceres. There are four more planetary objects*, namely Orcus, Sedna, Gonggong and Quaoar, that the majority of the scientific community recognize as dwarf planets.
Six more could be recognized in the coming years, and as many as 200 or more are hypothesized to exist in the Outer Solar System in the aforementioned Kuiper belt.
Ceres is the earliest known and smallest of the current category of dwarf planets. Previously classified as an asteroid in 1801, it was confirmed to be a dwarf planet in 2006. Ceres lies between Mars and Jupiter in the asteroid belt, and it is the only dwarf planet that orbits closest to Earth.
Here is a brief introduction to the most recognized dwarf planets:
Interesting Facts About Dwarf Planets
Here are a few interesting facts about the dwarf planets discovered in our solar system:
Ceres loses 6kg of its mass in steam every second
The Herschel Space Telescope observed plumes of water vapor shooting up from Ceres’ surface; this was the first definitive observation of water vapor in the asteroid belt. This happens when portions of Ceres’ icy surface warm up and turn into steam.
A day on Haumea lasts 3.9 hours
Haumea has a unique appearance due to its rotation, which is so rapid that it compresses the planet into an egg-like shape. Its rotational speed and collisional origin also make Haumea one of the densest dwarf planets discovered to date.
Makemake was named three years after its discovery in 2005
Makemake’s discovery close to Easter influenced both its name and nickname. Before being named after the creator of humanity and god of fertility in the mythos of the Rapa Nui (the native people of Easter Island), Makemake was nicknamed “Easter bunny” by its discoverer Mike Brown.
Eris was once considered for the position of the 10th planet
Eris is the most massive dwarf planet in the solar system, exceeding Pluto’s mass by 28%. As such, it was a serious contender to become the tenth planet but failed to meet the criteria set out by the IAU.
Pluto is one-third ice
The planet’s composition makes up two-thirds rock and one-third ice, mostly a mixture of methane and carbon dioxide. One day on Pluto is 153.6 hours, approximately 6.4 Earth days, making it one of the slowest rotating dwarf planets.
Exploratory Missions and New Planets on the Horizon
As this stunning animation suggests, dwarf planets may outnumber regular planets hundredfold or even thousandfold.
With newer technology rapidly available to the scientific community and new exploratory missions getting more data and information about trans-Neptunian objects, our understanding of dwarf planets will increase.
Nestled in the asteroid belt between Mars and Jupiter, the asteroid Hygiea remains a controversy. Hygiea is the fourth largest object in the asteroid belt behind Ceres, Vesta, and Pallas and ticks all the boxes necessary to be classified as a dwarf planet.
So what’s holding back Hygiea’s confirmation as a dwarf planet? The criterion for being massive enough to form a spherical shape is in contention; it remains unclear if its roundness results from collision/impact disruption or its mass/gravity.
Along with Hygiea, other exciting dwarf planets could be soon discovered. Here is a quick rundown of some serious contenders:
120347 Salacia
Discovered in 2004, it is a trans-Neptunian object in the Kuiper belt, approximately 850 kilometers in diameter. As of 2018, it is located about 44.8astronomical units from the Sun. Salacia’s status is in contention because its planetary density is arguable. It is uncertain if it can exist in hydrostatic equilibrium.
(307261) 2002 MS4
With an estimated diameter of 934±47 kilometers, 2002 MS4 is comparable in size to Ceres. Researchers need more data to determine whether 2002 MS4 is a dwarf planet or not.
(55565) 2002 AW197
Discovered at the Palomar Observatory in 2002, it has a rotation period of 8.8 hours, a moderately red color (similar to Quaoar) and no apparent planetary geology. Its low albedo has made it difficult to determine whether or not it is a dwarf planet.
174567 Varda
Varda takes its name after the queen of the Valar, creator of the stars, one of the most powerful servants of almighty Eru Iluvatar in J. R. R. Tolkien’s fictional mythology. Varda’s status as a dwarf planet is uncertain because its size and albedo suggest it might not be a fully solid body.
(532037) 2013 FY27
This space object has a surface diameter of about 740 kilometers. It orbits the Sun once every 449 years. Researchers need more data on the planet’s mass and density to determine if it is a dwarf planet or not.
(208996) 2003 AZ84
It is approximately 940 kilometers across its longest axis, as it has an elongated shape. This shape is presumably due to its rapid rotation rate of 6.71 hours, similar to that of other dwarf planets like Haumea. Like Varda, it remains unknown if this object has compressed into a fully solid body and thus remains contentious amongst astronomers regarding its planetary status.
*Note: The International Astronomical Union (IAU) officially recognizes five dwarf planets. We include four additional dwarf planets widely acknowledged by members of the scientific community, especially amongst leading planetary researchers like Gonzalo Tancredi, Michael Brown, and William Grundy. There are many more potential dwarf planets not listed here that remain under investigation.
To finish World Space Week 2021, here on “The Science Probe” I’d like to share the latest news about where NASA chose to set the Perseverance rover. Named after world renowned author Octavia E. Butler. Happy Women In Space 🌌!
Octavia E. Butler Landing is the 18 February 2021 landing site of the Mars 2020 Perseverance rover within Jezero crater on planet Mars. On 5 March 2021, NASA named the site for the renowned American science fiction author, Octavia E. Butler, who died on 24 February 2006. The Mars landing took place nearly 15 years to the day after her death.
Perseverance rover confirms existence of ancient Mars lake and river delta
By Mike Wall
The new results will help mission team members plan out the rover’s next moves.
Inferred paleolake level inside Mars’ Jezero Crater at the time of Kodiak sediment deposition. The red star indicates the Octavia E. Butler (OEB) landing site of NASA’s Perseverance rover. Background from the Context Camera (CTX) mosaic.
(Image credit: NASA/JPL-Caltech/MSSS/LPG)
NASA chose the landing site of its life-hunting Perseverance Mars rover wisely.
Perseverance touched down in February on the floor of the 28-mile-wide (45 kilometers) Jezero Crater, which was picked primarily because previous observations by Mars orbiters suggested that it hosted a big lake and a river delta in the ancient past.
Photos snapped by Perseverance early in its mission, before the car-sized robot even started roving, confirm this interpretation, a new study reports.
“Without driving anywhere, the rover was able to solve one of the big unknowns, which was that this crater was once a lake,” study co-author Benjamin Weiss, a professor of planetary sciences at the Massachusetts Institute of Technology, said in a statement. “Until we actually landed there and confirmed it was a lake, it was always a question.”
This image from the HiRISE camera onboard NASA’s Mars Reconnaissance Orbiter shows an orbital view of the delta fan in Jezero Crater and the Perseverance rover’s landing site, informally named Octavia E. Butler. The hill named Kodiak, the Delta Scarp and the location of boulder-rich material are also depicted.
(Image credit: NASA/JPL-Caltech/University of Arizona)
A good site for a bold mission
Perseverance has two main tasks during its $2.7 billion mission: hunt for signs of past Mars life and collect and cache dozens of samples for future return to Earth. (The rover also supported and documented the first few sorties of its traveling companion, NASA’s Ingenuity Mars helicopter, which is now flying more independently on the Red Planet.)
Jezero Crater was deemed a good place to do this work, based on data gathered by spacecraft such as NASA’s Mars Reconnaissance Orbiter. Orbital imagery showed a fan-shaped feature in Jezero that mission team members interpreted as a delta — a place where a river emptied into a lake about 3.7 billion years ago, depositing sediments that could harbor evidence of ancient Martian microbes, if any ever existed.
In the new study, which was published online today (Oct. 7) in the journal Science, researchers analyzed early photos that Perseverance snapped of this putative delta from afar with its Mastcam-Z imaging suite and a camera on its rock-zapping SuperCam instrument.
These photos captured the edge of the large delta outcrop as well as an isolated butte dubbed “Kodiak,” which the team thinks is an erosional remnant of the same formation. The Kodiak imagery was especially sharp, and the team saw in it distinct layers of sediment that could only have been deposited by a river flowing into a lake.
Sedimentary rock layers in the hill Kodiak, inside Mars’ Jezero Crater.
The upper image shows a photo taken by the Perseverance rover’s Mastcam-Z camera from a distance of about 1.39 miles (2.24 kilometers).
The lower image shows a SuperCam Remote Microscopic Imager mosaic showing distinctive inclined beds sandwiched between horizontal beds that are telltale signs of deposition in a delta environment.
The Kodiak observations “point unambiguously toward a deposition of river [sediments] with a delta and a lake,” study co-lead author Nicolas Mangold, of the French National Center for Scientific Research and the University of Nantes, told Space.com via email. (The other co-lead author is Sanjeev Gupta, of Imperial College London.)
“This helps us to constrain the lake level and will help us to build a scenario of the delta formation and lake activity along Perseverance’s traverse, and also identify the right layers to analyze and sample,” Mangold said.
Interestingly, Perseverance’s observations show that the ancient Jezero lake was about 330 feet (100 meters) lower than orbital data had suggested, “marking a phase of the delta well after the start of its formation,” Mangold said.
“We cannot extrapolate to the start of Jezero evolution, before the deposition of the material at Kodiak, because the corresponding layers are hidden further away in the delta,” he added. “But Perseverance might be able to give more results on that when it will cross the delta.”
Detail of boulder beds within Jezero Crater’s delta scarp, photographed by the Perseverance rover’s SuperCam Remote Microscopic Imager. These boulders were moved by highly energetic flows of water, scientists say.
Jezero is bone-dry today, like the rest of the Martian surface. Scientists think the Red Planet dried out about 3.5 billion years ago, after its global magnetic field died and its once-thick atmosphere became susceptible to stripping by charged particles streaming from the sun.
The newly analyzed photos may provide an intriguing glimpse into this big shift. For example, Perseverance’s imagery also shows big boulders, some up to 5 feet (1.5 m) wide, in the upper (younger) layers of Jezero’s main delta outcrop. It took a powerful flow to transport such large rocks — likely a flood that moved up to 106,000 cubic feet (3,000 cubic m) of water per second, study team members said.
Such flows may have resulted from “glacial surges” or rainfall-induced flash floods like those that occur in some of Earth’s desert regions today, Mangold said. Regardless of the cause, the boulder-bearing deposits could point to a very different Jezero than the one that produced the earlier lake sediments.
“The most surprising thing that’s come out of these images is the potential opportunity to catch the time when this crater transitioned from an Earth-like habitable environment to this desolate landscape wasteland we see now,” Weiss said in the same statement. “These boulder beds may be records of this transition, and we haven’t seen this in other places on Mars.”
Kodiak Hill what could have been an island in the edge of the proto-lake.
Perseverance will eventually get some up-close looks at the delta formation, if all goes according to plan. The team aims to drive the rover, which has traveled 1.62 miles (2.61 km) on Jezero’s floor to date, over to the delta outcrop and collect samples deposited during the calm-lake era. (Perseverance has already collected two of a planned several dozen samples, which will be hauled to Earth by a joint NASA-European Space Agency campaign, perhaps as early as 2031.)
But Perseverance, and NASA’s other Mars robots, are temporarily standing down because the Red Planet is on the other side of the sun from Earth at the moment. Our star can corrupt Mars-bound commands in the current planetary configuration, so NASA has imposed a two-week communications blackout that ends on Oct. 16.
Too late for a dip and a swim on Mars, but you could have once upon a time.
Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook, well not Facebook cause they are poisonous. ☠️
Cover Image Editor’s Notation: We are highlighting artwork that helps to understand where these celestial names come from in history and our western art.
“Large bronze statue of the Giant Mimas”
In Greek mythology, Mimas was one of the Gigantes (Giants), the offspring of Gaia, born from the blood of the castrated Uranus. According to the mythographer Apollodorus, he was killed during the Gigantomachy, the cosmic battle of the Giants with the Twelve Olympians.
Hey There Rebel Scum! The is a reason that we have lately been doing posts called “In Depth” is because we are focusing on water world’s in our solar system. As we are discovering as we find more Exo-Worlds is that the key to life is “Water!” 🌊 So we have been doing posts about special worlds in our System of Sol. Mimas is special because it’s the first Moon of Saturn 🪐.
Mimas the closest Moon to Saturn designating it Saturn I 🪐
Discovery
Mimas was discovered on Sept. 17, 1789 by English astronomer William Herschel, using his 40-foot reflector telescope.
Ground-based astronomers could only see Mimas as little more than a dot until Voyagers I and II imaged it in 1980. The Cassini spacecraft made several close approaches and provided detailed images of Mimas.
Overview
Less than 123 miles (198 kilometers) in mean radius, crater-covered Mimas is the smallest and innermost of Saturn’s major moons. It is not quite big enough to hold a round shape, so it is somewhat ovoid with dimensions of 129 x 122 x 119 miles (207 x 197 x 191 kilometers, respectively). Its low density suggests that it consists almost entirely of water ice, which is the only substance ever detected on Mimas.
At a mean distance just over 115,000 miles (186,000 kilometers) from the massive planet, Mimas takes only 22 hours and 36 minutes to complete an orbit. Mimas is tidally locked: it keeps the same face toward Saturn as it flies around the planet, just as our Moon does with Earth.
Most of the Mimas surface is saturated with impact craters ranging in size up to greater than 25 miles (40 kilometers) in diameter. However, the craters in the South Pole region of Mimas are generally 12.4 miles (20 kilometers) in diameter or less. This suggests that some melting or other resurfacing processes occurred there later than on the rest of the moon. (Interestingly, the South Pole area of Enceladus appears to be the source of that moon’s geysers.)
A Size by Size Comparison Between Science Fact and Science Fiction
The Empire’s first ultimate weapon is 120 Kilometers in circumference. With a diameter of 396 kilometres, Mimas is the smallest astronomical body that is known to still be rounded in shape because of self-gravitation. Which makes it almost three times the size of the first Imperial super weapon.
Its most distinguishing feature is a giant impact crater – named Herschel after the moon’s discoverer – which stretches a third of the way across the face of the moon, making it look like the Death Star from “Star Wars.” The Herschel Crater is 80 miles (130 kilometers) across – one third of the diameter of the moon itself – with outer walls about 3 miles (5 kilometers) high and a central peak 3.5 miles (6 km) high. The impact that blasted this crater out of Mimas probably came close to breaking the moon apart. Shock waves from the Herschel impact may have caused the fractures, also called chasmata, on the opposite side of Mimas.
That Mimas appears to be frozen solid is puzzling because Mimas is closer to Saturn and has a much more eccentric (elongated) orbit than Enceladus, which should mean that Mimas has more tidal heating than Enceladus. Yet Enceladus displays geysers of water, which implies internal heat, while Mimas has one of the most heavily cratered surfaces in the solar system, which suggests a frozen surface that has persisted for enough time to preserve all those craters. This paradox has prompted the “Mimas Test” by which any theory that claims to explain the partially thawed water of Enceladus must also explain the entirely frozen water of Mimas.
How Mimas Got its Name
Mimas passes through the Saturian rings.
The mythological Mimas was a giant who was killed by Mars in the war between the Titans and the gods of Olympus. Even after his death, Mimas’ legs – which were serpents – hissed vengeance and sought to attack his killer.
Mimas was named by John Herschel, the son of discoverer William Herschel, who explained his choice of names for the first seven of Saturn’s moons to be discovered by writing, “As Saturn devoured his children, his family could not be assembled round him, so that the choice lay among his brothers and sisters, the Titans and Titanesses.”
Astronomers also refer to Mimas as “Saturn I” based on its distance being the closest to Saturn. The International Astronomical Union now controls the official naming of astronomical bodies.
Cover Image Editor’s Notation: We are highlighting artwork that helps to understand where these celestial names come from in history and our western art.
“Ceres with Cereals”
A late 18th century work by Dominik Auliczek of the Nymphenburg Porcelain Manufactory.
Hey There Beltalowdas! The is a reason that we have lately been doing posts called “In Depth” is because we are focusing on water world’s in our solar system. As we are discovering as we find more Exo-Worlds is that the key to life is “Water!” 🌊 So we have been doing posts about special worlds in our System of Sol. Ceres is special because it’s a Dwarf Planet that lives in the asteroid belt.
1) Scientists would like to search for possible signs of life on Ceres. It has something many other planets don’t: water.
2) This orthographic projection shows dwarf planet Ceres as seen by NASA’s Dawn spacecraft.
Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Dwarf planet Ceres is the largest object in the asteroid belt between Mars and Jupiter, and it’s the only dwarf planet located in the inner solar system. It was the first member of the asteroid belt to be discovered when Giuseppe Piazzi spotted it in 1801. When NASA’s Dawn arrived in 2015, Ceres became the first dwarf planet to receive a visit from a spacecraft.
Called an asteroid for many years, Ceres is so much bigger and so different from its rocky neighbors that scientists classified it as a dwarf planet in 2006. Even though Ceres comprises 25% of the asteroid belt’s total mass, Pluto is still 14 times more massive.
Namesake
Ceres is named for the Roman goddess of corn and harvests. The word cereal comes from the same name.
Potential for Life
Ceres is one of the few places in our solar system where scientists would like to search for possible signs of life. Ceres has something a lot of other planets don’t: water. Here on Earth, water is essential for life, so it’s possible that with this ingredient and a few other conditions met, life possibly could exist there. If anything does live on Ceres, it’s likely to be very small microbes similar to bacteria. If Ceres does not have living things today, there may be signs it harbored life in the past.
Size and Distance
Ceres makes up almost a third of the asteroid belt’s total mass, but it is still far smaller than Earth’s Moon. Ceres is heavily cratered with large amounts of ice underground. Ceres completes one rotation around its axis every 9 hours. Ceres is so much bigger and so different from its neighbors that scientists classified it as a dwarf planet in 2006.
With a radius of 296 miles (476 kilometers), Ceres is 1/13 the radius of Earth. If Earth were the size of a nickel, Ceres would be about as big as a poppy seed.
From an average distance of 257 million miles (413 million kilometers), Ceres is 2.8 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes sunlight 22 minutes to travel from the Sun to Ceres.
Often, the names of features on planetary bodies are connected through a specific theme — for example, many features on the Moon have been named after famous scientists.
⬆️ This is a wonderful interactive map of the Solar System where you can find out the location of any system body in real time!
Orbit and Rotation
Ceres takes 1,682 Earth days, or 4.6 Earth years, to make one trip around the Sun. As Ceres orbits the Sun, it completes one rotation every 9 hours, making its day length one of the shortest in the solar system.
Ceres’ axis of rotation is tilted just 4 degrees with respect to the plane of its orbit around the Sun. That means it spins nearly perfectly upright and doesn’t experience seasons like other more tilted planets do.
Moons
Ceres does not have any moons.
Rings
Ceres does not have any rings.
Formation
This simulated perspective view shows Occator Crater, measuring 57 miles (92 kilometers) across and 2.5 miles (4 kilometers) deep, which contains the brightest area on Ceres.
Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Ceres formed along with the rest of the solar system about 4.5 billion years ago when gravity pulled swirling gas and dust in to become a small dwarf planet. Scientists describe Ceres as an “embryonic planet,” which means it started to form but didn’t quite finish. Nearby Jupiter’s strong gravity prevented it from becoming a fully formed planet. About 4 billion years ago, Ceres settled into its current location among the leftover pieces of planetary formation in the asteroid belt between Mars and Jupiter.
Structure
Ceres is more similar to the terrestrial planets (Mercury, Venus, Earth, and Mars) than its asteroid neighbors, but it is much less dense. One of the similarities is a layered interior, but Ceres’ layers aren’t as clearly defined. Ceres probably has a solid core and a mantle made of water ice. In fact, Ceres could be composed of as much as 25 percent water. If that is correct, Ceres has more water than Earth does. Ceres’ crust is rocky and dusty with large salt deposits. The salts on Ceres aren’t like table salt (sodium chloride), but instead are made of different minerals like magnesium sulfate.
Surface
Ceres is covered in countless small, young craters, but none are larger than 175 miles (280 kilometers) in diameter. This is surprising, given that the dwarf planet must have been hit by numerous large asteroids during its 4.5 billion-year lifetime.
The lack of craters might be due to layers of ice just below the surface. The surface features could smooth out over time if ice or another lower-density material, such as salt, is just below the surface. It’s also possible that past hydrothermal activity, such as ice volcanoes, erased some large craters.
Within some of Ceres’ craters, there are regions that are always in shadow. It’s possible that without direct sunlight, these “cold traps” could have water ice in them for long periods of time.
Atmosphere
Ceres has a very thin atmosphere, and there is evidence it contains water vapor. The vapor may be produced by ice volcanoes or by ice near the surface sublimating (transforming from solid to gas).
Magnetosphere
Scientists don’t think Ceres has a magnetosphere.
Ceres in Pop Culture
The largest body in the asteroid belt, Ceres has amassed a number of references in science fiction stories of the 20th and 21st centuries. In the TV series “The Expanse,” Ceres is inhabited by humans, and in the PC Game Descent, one of the secret levels takes place on Ceres.
In the video game Destiny, Ceres was colonized by an alien race called the Fallen at the end of humanity’s Golden Age. Ceres was later destroyed by a civilization of post-humans who inhabit the asteroid belt.
Ceres as a location is a major star in the Science Fiction world of “The Expanse”. So much of the first season takes place here as the mystery of Julie Andromeda Mao is unraveled by Joseph Miller. It’s on Ceres that we meet the young Belter – Diogo who gets caught up in the Outer Planets Association “OPA”. When we meet him the first time he and his gang are caught “stealing” water from the condensation from the pipes of the station. With the suspected ice under the thin crust of the dwarf. Science asks would the inhabitants of Ceres really need to resort to such theft for their thirst?
If NASA is correct here in still 4, The TV show may be getting one thing incorrect. (Which is sad because of all they get right with their “science”) If we are correct there could be quite a bit of frozen ice that makes up Ceres. So let’s pretend that over the century that the Belters have resided there they used it all up.
The many faces of the underground worlds of Ceres in “The Expanse”. Do the wealthy consider themselves as “Beltalowdas” like the working poor? On the TV series we get the impression that these levels never mingle.
Cover Image Editor’s Notation: We are highlighting artwork that helps to understand where these celestial names come from in history and our western art.
“The Rape of Ganymede”
The drawing depicts the myth of the beautiful young shepherd Ganymede of Troy, abducted by the god Jupiter in the form of an eagle and carried away to Olympus, where Jupiter made him his cup-bearer. It is, in all probability, a partial copy of a presentation drawing in vertical format made late in 1532 by Michelangelo for Tommaso de’ Cavalieri. Michelangelo’s drawing is probably lost, though various versions have been claimed as the original. Michelangelo’s originally vertical composition. (Adapted from Joannides 1996, no. 15).
Ganymede is a differentiated body. This means that it has a discernable core and mantle/crust, much like planets do. Ganymede’s core is liquid iron, like earth’s. It is tidally locked to Jupiter, which means that the same side of the moon faces the planet, again like our earth. Ganymede also has its own magnetic field and atmosphere.
Jupiter’s moon Ganymede (“GAN uh meed”) is the largest moon in our solar system and the only moon with its own magnetic field. The magnetic field causes auroras, which are ribbons of glowing, electrified gas, in regions circling the moon’s north and south poles. When Jupiter’s magnetic field changes, the aurorae on Ganymede also change, “rocking” back and forth.
Ganymede also has large, bright regions of ridges and grooves that slice across older, darker terrains. These grooved regions are a clue that the moon experienced dramatic upheavals in the distant past.
In 2015, NASA’s Hubble Space Telescope found the best evidence to date for an underground saltwater ocean on Ganymede. The subterranean ocean is thought to have more water than all the water on Earth’s surface.
Ganymede has three main layers. A sphere of metallic iron at the center (the core, which generates a magnetic field), a spherical shell of rock (mantle) surrounding the core, and a spherical shell of mostly ice surrounding the rock shell and the core. The ice shell on the outside is very thick, and about 500 miles (800 kilometers) thick. The surface is the very top of the ice shell. Though it is mostly ice, the ice shell might contain some rock mixed in. Scientists believe there must be a fair amount of rock in the ice near the surface. Ganymede’s magnetic field is embedded inside Jupiter’s massive magnetosphere.
One of the first images of Ganymede taken by NASA’s Juno spacecraft during a June 7, 2021, flyby of Jupiter’s giant moon.
Credits: NASA/JPL-Caltech/SwRI
Astronomers using Hubble found evidence of a thin oxygen atmosphere on Ganymede in 1996. The atmosphere is far too thin to support life as we know it.
In 2004, scientists discovered irregular lumps beneath the icy surface of Ganymede. The irregular masses may be rock formations, supported by Ganymede’s icy shell for billions of years. This tells scientists that the ice is probably strong enough, at least near the surface, to support these possible rock masses from sinking to the bottom of the ice. However, this anomaly could also be caused by piles of rock at the bottom of the ice.
Check out this informative 3D model of this huge water world.
This image of the dark side of Ganymede was obtained by Juno’s Stellar Reference Unit navigation camera during its June 7, 2021, flyby of the moon.
Credits: NASA/JPL-Caltech/SwRI
Spacecraft images of Ganymede show the moon has a complex geological history. Ganymede’s surface is a mixture of two types of terrain. Forty percent of the surface of Ganymede is covered by highly cratered dark regions, and the remaining sixty percent is covered by a light grooved terrain, which forms intricate patterns across Ganymede.
On June 7, 2021, NASA’s Juno spacecraft made a flyby of Ganymede. The photos – one from the Jupiter orbiter’s JunoCam imager and the other from its Stellar Reference Unit star camera – show the surface in remarkable detail, including craters, clearly distinct dark and bright terrain, and long structural features possibly linked to tectonic faults.
“This is the closest any spacecraft has come to this mammoth moon in a generation,” said Juno Principal Investigator Scott Bolton of the Southwest Research Institute in San Antonio. “We are going to take our time before we draw any scientific conclusions, but until then we can simply marvel at this celestial wonder – the only moon in our solar system bigger than the planet Mercury.”
1) Ganymede is the largest moon around the planet Jupiter. Ganymede is also the biggest moon in the solar system. Ganymede is roughly three thousand miles across, making it bigger than the planet Mercury. If Ganymede was orbiting the Sun, it would be considered a planet. Ganymede is large enough to be pulled into a sphere by its gravity.
2) Ganymede vs Mercury. The largest moon in the Solar System is bigger than the smallest planet in the Solar System!
3) Two of the moons in our solar system (Ganymede & Titan) are actually larger than the planet Mercury.
4) Jupiter’s moon Ganymede has a diameter about 389 km wider than that of the planet Mercury. But it is considerably less dense. The reason we believe it’s less dense is because we know it has water under it’s frozen shell, because of it’s iron core the moon heats up that water. It is reasoned that here microbes could exist and even life.
Ganymede’s grooved terrain probably is the result of tensional faulting or the release of water from beneath the surface. Groove ridges as high as 2,000 feet (700 meters) have been observed and the grooves run for thousands of miles across Ganymede’s surface. The grooves have relatively few craters and probably developed at the expense of the darker crust. The dark regions on Ganymede are old and rough, and the dark cratered terrain is believed to be the original crust of the satellite. Lighter regions are young and smooth (unlike Earth’s Moon). The largest area on Ganymede is called Galileo Regio.
The large craters on Ganymede have almost no vertical relief and are quite flat. They lack central depressions common to craters often seen on the rocky surface of the Moon. This is probably due to a slow and gradual adjustment to the soft icy surface. These large phantom craters are called palimpsests, a term originally applied to reused ancient writing materials on which older writing was still visible underneath newer writing. Palimpsests range from 30 to 250 miles (50 to 400 kilometers) in diameter. Both bright and dark rays of ejecta exist around Ganymede’s craters – rays tend to be bright from craters in the grooved terrain and dark from the dark cratered terrain.
Discovery
Ganymede was discovered by Galileo Galilei on Jan. 7, 1610. The discovery, along with three other Jovian moons, was the first time a moon was discovered orbiting a planet other than Earth. The discovery of the four Galilean satellites eventually led to the understanding that planets in our solar system orbit the Sun, instead of our solar system revolving around Earth.
Draft of a letter to Leonardo Donato, Doge of Venice, August, 1609, and Notes on the Moons of Jupiter, January 1610.
Image Credit: University of Michigan Special Collections Library
Simon Marius probably made an independent discovery of the moons at about the same time that Galileo did, and he may have unwittingly sighted them up to a month earlier, but Galileo was the first to publish his discovery.
How Ganymede Got its Name
Ganymede is named after a boy who was made cupbearer for the ancient Greek gods by Zeus – Jupiter to the Romans.
Galileo originally called Jupiter’s moons the Medicean planets, after his patrons, the Medici family. He referred to the individual moons numerically as I, II, III, and IV. Galileo’s naming system was used for a couple of centuries.
It wouldn’t be until the mid-1800’s that the names of the Galilean moons, Io, Europa, Ganymede, and Callisto, would be officially adopted, and only after it became apparent that naming moons by number would be very confusing as new additional moons were being discovered.
Cover Image: Editor’s Notation
The Rape of Ganymede
The drawing depicts the myth of the beautiful young shepherd Ganymede, abducted by the god Jupiter in the form of an eagle and carried away to Olympus, where Jupiter made him his cup-bearer. It is, in all probability, a partial copy of a presentation drawing in vertical format made late in 1532 by Michelangelo for Tommaso de’ Cavalieri. Michelangelo’s drawing is probably lost, though various versions have been claimed as the original. Michelangelo’s originally vertical composition. (Adapted from Joannides 1996, no. 15). Source: Wikipedia
Editors Note: Valentina Vladimirovna Tereshkova is one of my favorite historical figures, and at the time of this posting she is still with us at the age of 84. I admire her and Yuri Gagarin because of their accomplishments as Cosmonauts and all the things they managed to do with their lives. Yuri was taken from us too early, yet as a woman Valentina accomplished so many things for both of them. In fact because of her gender and the country she belongs to, I’d like to think she has done more for her country and our world.
This post is here to celebrate the World Space Week theme “Women In Space” 🚀👩🚀
Who Is Valentina Tereshkova?
As a young woman, Valentina Tereshkova worked in a textile mill and parachuted as a hobby. She was chosen to be trained as a cosmonaut in the USSR’s space program. On June 13, 1963, she became the first woman to travel into space. In just under three days, she orbited the earth 48 times. After her space flight, she served in the Communist Party and represented the USSR at numerous international events.
Early Life
The second of three children born to Vladimir Tereshkova and Elena Fyodorovna Tereshkova, Valentina Tereshkova was born on March 6, 1937 in Bolshoye Maslennikovo, a village in western Russia. When she was two years old, father was killed fighting in World War II. Her mother raised Valentina, her sister Ludmilla and her brother Vladimir, supporting the family by working in a textile mill.
Valentina began attending school when she was eight or 10 (accounts vary), and then started working in the textile mill in 1954. She continued her education through correspondence courses, and learned to parachute in her spare time. It was her parachuting experience that led to her being chosen, in 1962, for training as a cosmonaut in the Soviet space program. During the late 1950s and 1960s, the Space Race between the United States and the Soviet Union escalated for space travel supremacy. The competitiveness between the two nations for “one upping” achievements was fierce and the Soviets were determined to be the first to send a woman into space.
Cosmonaut Career
Valentina Vladimirovna Tereshkova is the first and youngest woman to have flown in space with a solo mission on the Vostok 6 on 16 June 1963. She orbited the Earth 48 times, spent almost three days in space, and remains the only woman to have been on a solo space mission.
Four women were chosen to become cosmonauts, but only Tereshkova actually went into space. On June 16, 1963, Vostok 6 was launched, with Tereshkova aboard. The first woman to travel in space, she called out, “Hey sky, take off your hat. I’m on my way!” as the craft took off. Tereshkova orbited the earth 48 times in 70.8 hours—just under three days. (By way of comparison, Yuri Gagarin, the first man in space, orbited the earth once; and the four American astronauts who flew before Tereshkova orbited a total of 36 times.) While she was orbiting, she spoke with Soviet leader Nikita Khrushchev, who said, “Valentina, I am very happy and proud that a girl from the Soviet Union is the first woman to fly into space and to operate such cutting-edge equipment.”
When she returned from her voyage—parachuting from her space craft to earth from 20,000 feet—Tereshkova was given the title Hero of the Soviet Union.
Despite the success of Tereshkova’s flight, it was 19 years before another woman (Svetlana Savitskaya, also from the USSR) traveled to space. Many accounts suggest that women cosmonauts did not receive the same treatment as their male counterparts. The first American woman to go to space was Sally Ride in 1983.
Personal Life
Valentina and Andriyan Nikolayev’s wedding ceremony, 3 November 1963
Valentina married cosmonaut Andriyan Nikolayev on 3 November 1963 at the Moscow Wedding Palace with Khrushchev presiding at the wedding party together with top government and space programme leaders. The marriage was encouraged by the Soviet space authorities as a “fairy-tale message to the country”. General Kamanin, head of the space program, described it as “probably useful for politics and science”. On 8 June 1964, nearly one year after her space flight, she gave birth to their daughter Elena Andrianovna Nikolaeva-Tereshkova, the first person with both a mother and father who had travelled into space.
Later in their marriage, the couple grew apart and refused to even stand next to each other in photographs. Tereshkova told the biographer Lady Lothian that the marriage ended in 1977; she and Nikolayev divorced in 1980 and Tereshkova married Yuli Shaposhnikov, a surgeon she had met during her medical examinations to re-qualify as a cosmonaut. They remained married until Shaposhnikov’s death in 1999.
2) Tereshkova among delegates at the 24th Congress of the CPSU, 1971
3) Tereshkova with American communist Angela Davis in 1973 East Berlin, East Germany
4) Tereshkova with South Korean President Moon Jae-in in the Russian State Duma, 2018
Tereshkova graduated with distinction from the Zhukovsky Military Air Academy in 1969. She became a prominent member of the Communist Party, and represented the USSR at numerous international events, including the United Nations conference for the International Women’s Year in 1975. She headed the Soviet Committee for Women from 1968-87, was pictured on postage stamps, and had a crater on the moon named after her.
In 2007, Vladimir Putin invited Tereshkova to celebrate her 70th birthday. At the time, she said, “If I had money, I would enjoy flying to Mars.” In 2015, her space craft, Vostov 6, was displayed as part of an exhibit at the Science Museum in London called “Cosmonauts: Birth of the Space Age.” Tereshkova attended the opening, and spoke lovingly about her spacecraft, calling it “my lovely one” and “my best and most beautiful friend – my best and most beautiful man.”
Awards and Honours
Merited Master of Sports of the Soviet Union (June 1963)
Hero of the Soviet Union (1963)
Order of Lenin (1963, 1981)
Order of the October Revolution (1971)
Order of the Red Banner of Labour (1987)
Order of the Friendship of Peoples
Pilot-Cosmonaut of the Soviet Union (1963)
Gold star Hero of Socialist Labor (Czechoslovakia, August 1963)
Gold star Hero of Socialist Labor (Bulgaria) (9 September 1963)
Order of Georgi Dimitrov (Bulgaria, 9 September 1963)
Order of Karl Marx (East Germany, October 1963)
Artur Becker Medal [de] (East Germany, October 1963)
Cross of Grunwald, 1st class (Poland, October 1963)
Order of the Flag of the Republic of Hungary, 1st class (April 1965)
Star of the Republic of Indonesia, 2nd class (November 1963)
Order of the Volta (Ghana, January 1964)
Gold Star Medal of the Hero of the Mongolian People’s Republic (May 1965)
Order of Sukhbaatar (Mongolia, May 1965)
Order of the Enlightenment (Afghanistan, August 1969)
Order of Planets (Jordan, December 1969)
Order of the Nile (Egypt, January 1971)
Gold Star of Hero of Labor (Vietnam, October 1971)
Order of Bernardo O’Higgins (Chile, March 1972)
Order of Ana Betancourt (Cuba, 1974)
Order of Friendship (Laos, 1997)
Order of Duke Branimir, with sash (Croatia, presented on 8 September 2005)
She received the Eduard Rhein Ring of Honor from the German Eduard Rhein Foundation in 2007.
Order of Merit for the Fatherland:
3rd class (6 March 1997)
2nd class (6 March 2007)
1st class (1 March 2017)
Order of Alexander Nevsky (2013)
Order of Honour (10 June 2003)
Order of Friendship (12 April 2011)
Russian Federation State Prize for outstanding achievements in the field of humanitarian action in 2008 (4 June 2009)
Participant of the Military Operation in Syria Medal [ru] (2016)
Strengthening the Military Community Medal [ru] (2018)
Certificates of appreciation from the Government of the Russian Federation; 3 March 1997, – for the contribution to the development of space, the strengthening of international scientific and cultural ties and years of diligent work
12 June 2003, – for large contribution to the development of manned space flight
16 June 2008, – for long-term fruitful state and public activities, considerable personal contribution to the development of manned space flight and in connection with the 45th anniversary of spaceflight
Gold Medal of the British Society for interplanetary communications “For achievements in space exploration” (February 1964)
Gold Space Medal (FAI, 1963)
Honorary doctorate from the University of Edinburgh (1990)
Order of St. Euphrosyne of Moscow (January 2008)
Legacy
1963 USSR Postage Stamp
Novopromyshna Square in Tver was renamed Tereshkova Square in 1963.
In 1967, Gregory Postnikov [ru] created a sculpture of Tereshkova for Cosmonaut Alley in Moscow. There is a monument in Bayevsky District of Altai Territory, Siberia, close to her landing place of 53°N, 80°E. In August 1970, Tereshkova was among the first group of living people to have a lunar crater named after them. Tereshkova crater is located on the far side of the Moon.
None of the other four in Tereshkova’s early group flew and, in October 1969, the pioneering female cosmonaut group was dissolved. Even though there were plans for further flights by women, it took 19 years until the second woman, Svetlana Savitskaya, flew into space.
In 1997, London-based electronic pop group Komputer released a song entitled “Valentina” which gives a more-or-less direct account of her career as a cosmonaut. It was released as a single and appears on their album The World of Tomorrow. The 2000 album Vostok 6 by Kurt Swinghammer is a concept album about Tereshkova. The 2015 album The Race for Space by Public Service Broadcasting also has a song featuring the Smoke Fairies entitled “Valentina”. In the same year, Findlay Napier’s album VIP: Very Interesting Persons included a song “Valentina”, written in her honour by Napier and Boo Hewerdine. In 2015, a short film entitled Valentina’s Dream was released by Meat Bingo Productions. The film stars Rebecca Front as Tereshkova and is based on an interview by the former cosmonaut where she expressed a desire to journey to Mars.
The Cosmos Museum was opened 25 January 1975 near Yaroslavl. Among its exhibits is a replica of her childhood home. The city library was named after her in 2013. The school she attended as a child was renamed for her. A planetarium in Yaroslavl was built and named for her in 2011. The International Women of the Year association named her as the “greatest woman achiever of the 20th century”. Tereshkova was a torchbearer of the 2008 Summer Olympics torch relay in Saint Petersburg and the 2014 Winter Olympics torch relay in Sochi.
Streets in Ukraine that bore Tereshkova’s name have been renamed due to her support of Russia’s military actions against Ukraine and it was done in accordance with the country’s 2015 decommunisation law. A proposal was also brought forward in 2015 to move a monument to Tereshkova in Lviv, Ukraine to the Territory of Terror Memorial Museum. Monuments of communist leaders are removed from the public and placed in the museum as a part of decommunization efforts. In January 2021, 24 Ukrainian streets were still named after Tereshkova; including a street in Busk, located in the same province as Lviv.
Cover Image Editor’s Notation: We are highlighting artwork that helps to understand where the these celestial names come from in history and our western art.
“Gilt-bronze Enceladus by Gaspar Mercy in the in the gardens of Versailles, outside of Paris France”
In Greek mythology, Enceladus (Ancient Greek: Ἐγκέλαδος, romanized: Enkélados) was one of the Giants, the offspring of Gaia (Earth), and Uranus (Sky). Enceladus was the traditional opponent of Athena during the Gigantomachy, the war between the Giants and the gods, and was said to be buried under Mount Etna in Sicily.
Enceladus is a small ocean world covered in ice — one of more than 60 confirmed moons orbiting Saturn. It’s 25 times smaller than Earth and almost 10 times as far from the sun, yet in recent years, it’s given scientists many reasons to think it should be the next target in our search for worlds where extraterrestrial life could exist.
So what has scientists so stoked about Enceladus? Here are some of the most intriguing findings scientists have made about Enceladus using data from NASA’s Cassini spacecraft at Saturn.
Enceladus is the sixth-largest moon of Saturn. It is about 500 kilometers in diameter, about a tenth of that of Saturn’s largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System.
A highly active world with surfaces that are still in their adolescence (less than 100 million years old), Enceladus may have big surprises in store the further we explore.
Insides Erupting Out
Jets of water vapor and ice particles erupt from Enceladus’ underground ocean through deep icy crevasses called Tiger Stripes near the moon’s south pole, providing clues about its inner-workings.
Putting a Ring on Saturn
Fast-moving ice particles escaping from Enceladus’ jets feed and replenish one of Saturn’s rings, called the E ring — a faint halo that lies beyond the brighter main rings.
Slipping and Sliding
The icy, cracked terrain stretching across Enceladus’ active south pole is in constant motion, stretching in some places and buckling in others as the cracks pinch and pull from gravitational forces.
Too Hot to Handle
An unusual amount of heat emanates from Enceladus’ south polar region in the same areas where jets spray from massive cracks. The moon’s ability to generate so much internal heat remains a mystery, but it bodes well for habitability.
Cool Chemistry
Organic compounds — the building blocks of life on Earth — along with volatile gases, water vapor, carbon dioxide, carbon monoxide, salts and silica have all been detected in Enceladus’ plume.
Water, Water Everywhere
A global ocean flows on Enceladus beneath an ice shell about 20 to 25 miles (30 to 40 kilometers) thick
Ingredients for Life
With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist.
Oceans help make life on Earth possible. So if there are oceans beyond Earth, do living things exist on those worlds, too? This is a question that NASA scientists are trying to answer. Right now, we know there are moons and dwarf planets in our solar system where oceans do exist. And there are more places where they could exist. To find out more, we will need to send spacecraft to study these places up close. But we already have some good clues to get us started.
Flip through the slideshow to see what we know about ocean worlds in our solar system. Which of these places do you think is most likely to have living things?
EARTH 🌍
Our home planet, Earth, is the only place we know of where life exists. Earth is called the “ocean planet” because it is covered mostly by water (71 percent water and 29 percent land).
Size: Earth has an equatorial circumference (the distance around its middle) of nearly 25,000 miles (40,000 km). Earth is not the biggest planet, but it is the biggest ocean world that we know of in our solar system.
Distance from the sun: On average, Earth is 1 astronomical unit, or AU, from the sun. That’s nearly 93 million miles (150 million kilometers)! When scientists search for worlds that may have living things, they look at the distance between those worlds and our sun. That’s because one of the things that makes our lives on Earth possible is our distance from the sun. We’re not too close to the sun, where it’s burning up, and we’re not too far away, where it’s really cold. That doesn’t mean that life doesn’t exist farther away from the sun. It just may be very different than what we have here on Earth.
Type of ocean world: Earth has what’s called an active ocean. That means that our oceans have systems and patterns that keep our planet working. Life on Earth would not exist without this active ocean.
Ceres isn’t a moon and it isn’t a planet. It is a dwarf planet. (Watch this video to find out what makes a dwarf planet different from a planet.) Scientists estimate that some of Ceres (about 25 percent by mass) is made of water. And some of that water might be in a liquid form. Based on computer models, scientists predict that Ceres has a significant liquid water reservoir, or even an ocean, far beneath the surface. In 2015, a NASA spacecraft called Dawn arrived at Ceres to find out more about it.
Size: The distance around the Ceres’ equator is 1,859 miles (2,992 km). It would take nearly 31 hours to drive all the way around Ceres’ equator if you were in a car going 60 miles per hour. That may sound like a long time, but driving around Earth would take more than 17 Earth days – and that’s without stopping!
Distance from the sun: On average, Ceres is about 2.8 AU from the sun. That’s almost three times farther than Earth is from the sun.
Type of ocean world: There are clues that Ceres may have salty liquid below the surface and that it could have had an ocean deep underground, but scientists can’t say for sure. So we’ll have to do more research. That makes Ceres a “possible ocean world.”
Scientists have strong evidence that there’s a salty ocean on Jupiter’s moon Europa beneath a layer of ice. Europa is stretched and squeezed by Jupiter’s gravity as it orbits the planet. This process heats Europa’s ocean and keeps it from freezing. The heat may also melt parts of the moon’s outer shell, creating lakes within the ice. NASA is designing a spacecraft that it will send to study Europa sometime in the 2020s.
Size: It would take more than four days to drive all the way around Europa at 60 miles per hour without stopping. The distance around its equator is 6,093 miles (9,807 km).
Distance from the sun: Europa orbits Jupiter, which is about 5.2 AU from the sun. That’s more than five times farther than Earth is from the sun.
Type of ocean world: There are lot of clues that Europa has an active ocean. If it does, that means the ocean may be moving chemical nutrients that are useful to microbes (tiny living things) from its rocky interior and icy crust into the ocean. If scientists can confirm that Europa’s ocean is active, it will be a major discovery. This is because similar cycles of activity affect Earth’s ocean and help make life here possible. For now, though, Europa’s ocean is thought of as “possibly active.”
Jupiter’s moon Ganymede is the largest moon in our solar system. It is also the only moon with its own magnetic field. Scientists have found clues that Ganymede may have a large, underground, saltwater ocean. The moon may even have several layers of ice and water sandwiched between its crust and core.
Size: Ganymede is the biggest moon in our solar system. It’s even bigger than Mercury! But it is still much smaller than Earth. It has a circumferences of about 10,300 miles (16,500 km). That is less than half of Earth’s circumference. It would take about seven days to drive all the way around the moon at 60 miles per hour without stopping.
Distance from the sun: Ganymede orbits Jupiter at 483 million miles (5.2 AU) from the sun. Given that the average school day is about 7 hours, it would take more than 1 million school days to drive to Ganymede from the sun at 60 miles per hour! Luckily, space travel is much faster than that.
Type of ocean world: While there is a good chance that Ganymede has an ocean, it’s less likely to have things living in it. That’s because the ocean is probably trapped between layers of ice. If it is trapped, there might not be a way for nutrients – key ingredients for life on Earth – to reach the ocean from above or below. So Ganymede is what we call a “locked” ocean world.
The deepest known place on Earth is the Mariana Trench in the Pacific Ocean. It is more than 6 miles deep. Jupiter’s moon Callisto may also have an ocean about that deep. But on Callisto, this ocean is trapped below an ice layer that is covered in craters and estimated to be 60 miles thick! So if Callisto were a layered cake, it would take a big fork to get down to the ocean layer.
Size: Callisto is just a little smaller than Ganymede. The circumference at its equator is about 9,400 miles (15,150 km).
Distance from the sun: Callisto orbits Jupiter with Ganymede and Europa at 5.2 AU from the sun.
Type of ocean world: Because of that thick ice layer covering Callisto’s ocean, it probably doesn’t have any creatures or other kinds of life inside it. Callisto, like Ganymede, is considered a “locked” ocean world.
Scientists have discovered there’s a global ocean inside Saturn’s moon Enceladus. This body of water is under the moon’s icy crust. But there are deep cracks (nicknamed “tiger stripes”) in the shell, near the south pole, that are letting some of the ocean’s water escape. While flying by Enceladus, NASA’s Cassini spacecraft took pictures of these jets of water escaping from the moon and even grabbed samples to determine what the jets are made of. (Check out our slideshow all about Enceladus to find out more.)
Size: Enceladus is pretty small, especially for one of Saturn’s moons. The circumference at its equator is 984 miles (1,584 km). That’s much smaller than Earth’s moon. It would only take 16 hours to drive around Enceladus at 60 miles per hour.
Distance from the sun: Enceladus orbits Saturn way out at 9.5 AU. Remember how long it would take us to drive to one of Jupiter’s moons from the sun? It would take almost twice that long to get to Saturn and its moons.
Type of ocean world: Thanks to those deep cracks in the ice near Enceladus’ south pole, its ocean isn’t trapped. Water from the ocean is shooting up to the surface through the cracks, providing “free samples” for spacecraft that pass by. By “tasting” these samples, the Cassini spacecraft found evidence that hot water full of minerals is pouring into the ocean from vents on the seafloor. There are even chemicals some Earth microbes could use for making food. This makes Enceladus an “active” ocean world. And it makes scientists think that Enceladus might be able to host living things.
Saturn’s moon Titan is covered in a thick haze that makes it hard to know what’s going on beneath it. But NASA’s Cassini mission has helped us make new discoveries. The Cassini spacecraft started exploring Saturn and its moons in 2004 and flew by Titan many times. The spacecraft also dropped a probe onto Titan that collected images and information as it floated down to the surface. Thanks to the mission, scientists now believe that Titan has a very salty ocean under its outer, icy crust. Since the ocean might be in contact with a rocky core, some scientists wonder if the ocean could be a place that has the chemical ingredients for life. Titan is a double ocean world since it also has lakes and seas on its surface. However, these features are made of chemicals that are not ideal for life as we know it on Earth.
Size: Titan is another large moon that is similar in size to Ganymede and Callisto. The circumference at its equator is about 10,000 miles (16,200 km). It would take about 7 days to drive around it at 60 miles per hour.
Distance from the sun: Titan also orbits Saturn at 9.5 AU from the sun. To appreciate how far that is, consider that the Cassini spacecraft traveled at an average speed of 10 miles per second to get to Saturn. Even at that speed, it took seven years to get to Saturn (with some twists and turns).
Type of ocean world: If the ocean inside Titan doesn’t reach the surface, then it is a “locked” ocean world. We probably wouldn’t find life in Titan’s ocean if it is locked because living things would have a hard time surviving in that kind of environment. But it is possible that life as we don’t know it could exist in the seas of liquid methane and ethane on Titan’s surface. The seas have tides and waves and are fed by rivers and rain, which makes them active places.
Scientists can study how a moon or planet moves to learn about what might be inside. Scientists who studied the movements of Saturn’s moon Mimas found that it wobbled much more than they expected. One reason might be that the moon could have an ocean 15 to 20 miles (25 to 30 km) below its surface. Or the wobble could be caused by a football-shaped core at the center of the moon. It will take more scientific study before anyone knows for sure what is below the surface of this crater-covered moon that looks strikingly similar to the Death Star from “Star Wars.”
Size: Mimas is tiny. The distance around its equator is about 800 miles (1,250 km). It would take about half a day to drive all the way around it at 60 miles per hour.
Distance from the sun: Mimas can be found near Saturn’s other moons at 9.5 AU from the sun. If you were to do a tour of Saturn’s possible ocean worlds from the ringed planet itself, you would reach Mimas first, then Enceladus and finally Titan.
Type of ocean world: Scientists are still trying to find out whether Mimas has an ocean at all. Until they do, they won’t know whether living things are likely to exist there. For now, Mimas is known as a “possible” ocean world.
Neptune’s moon Triton was named after a Greek god of the sea, but scientists aren’t sure whether there are any oceans on Triton. Geysers that spew nitrogen gas can be found all across the icy moon. There is also evidence of volcanic activity. All of this activity makes scientists wonder about the possibility of an ocean below Triton’s surface. Voyager 2 is the only spacecraft to have ever visited Triton and that was in 1989. So there is still more science that needs to be done before anyone can say for sure whether Triton is an ocean world.
Size: Triton is close in size to Jupiter’s moon Europa, which may be an active ocean world. The circumference at its equator is about 5,300 miles (8,500 km). It would take about the same amount of time to drive around Triton’s equator as it would to drive from Los Angeles to New York City and back.
Distance from the sun: Triton orbits Neptune, which is the most distant planet in our solar system. Neptune and its moons are 2.8 billion miles (4.5 billion km) or 30 AU from our sun!
Type of ocean world: Like Mimas, Triton is a “possible” ocean world. There’s evidence of an ocean, but it will take more studying to know for sure.
In 2015, NASA’s New Horizons spacecraft made the first up-close flyby of Pluto. The spacecraft collected new information and images that are helping scientists learn more about the faraway world. Even before the flyby, there was some evidence that Pluto has an ocean beneath its surface. Scientists are still studying all the new information they have collected. But we may get more clues about Pluto’s potential as an ocean world soon.
Size: Pluto is a little smaller than Triton. The circumference at its equator is about 4,500 miles (7,200 km). Pluto is called a “dwarf planet” partly because it is not big or massive enough to have cleared the debris around it. (Watch this video to find out what makes a dwarf planet different from a planet.)
Distance from the sun: Pluto is about 40 AU from the sun. That’s 3.7 billion miles (5.9 billion km)! It took the New Horizons spacecraft more than nine years to get from Earth to Pluto.
Type of ocean world: Scientists are still studying Pluto for signs of an ocean. So for now, it is in the same category as Ceres, Triton and Mimas – a “possible” ocean world.
The hefty rocket will launch the Artemis 1 moon mission, but first NASA has to put all the parts together and run a lot of tests.
This patriotic view from Sept. 17 shows an American flag with the SLS rocket under assembly at NASA’s Kennedy Space Center.
NASA/Frank Michaux
If you enjoy awe-inspiring feats of design and engineering, then take a moment out of your day to stare deeply into the latest images of NASA’s extremely large Space Launch System rocket. It’s the most powerful rocket NASA has ever built, and it shows in the grand scale of the beast.
SLS is coming together at the Kennedy Space Center in Florida where it will eventually be used to launch the uncrewed Artemis 1 mission to send an Orion spacecraft around the moon. While SLS has been expected to blast off as soon as this year, no one will be surprised if the big event slips into 2022.
SLS has multiple umbilicals that feed power, coolant, fuel and communications to the rocket. When the rocket ignites and lifts off, the umbilical arms swing out of the way. It’s an important bit of launch choreography. The URRT is all about making sure those systems are working correctly.
Artemis 1 will be a key first step to test SLS and the Orion spacecraft. There will be no humans on board, but it will set the stage for future crewed missions aimed at ultimately returning humans to the surface of our lunar neighbor. It’s been decades since people were last there during the Apollo era of the 1960s and 1970s.
The SLS core stage (the center part) stands 212 feet (65 meters) tall and weighs 188,000 pounds (85,275 kilograms). The Orion spacecraft will eventually be added to the top of SLS like a crown. When SLS finally launches, it will signal the beginning of the Artemis era and perhaps make the moon feel a little more in reach for humanity once again.
Path to the Pad: NASA Moon Rocket Comes Together for Artemis
Artemis 1
NASA’s Space Launch System (SLS) rocket is on its path to the pad for Artemis I, the first integrated mission of SLS and NASA’s Orion spacecraft through the agency’s Artemis program. Before it launches from NASA’s Kennedy Space Center in Florida, the agency’s Exploration Ground Systems (EGS) and Jacobs teams at the spaceport stack the different elements of the SLS rocket on top of the mobile launcher inside the iconic Vehicle Assembly Building. So large that it’s a Florida Space Coast landmark, the VAB as well as the mobile launcher have been specially outfitted to accommodate SLS and Orion. Once fully assembled, the upgraded crawler-transporter will carry the skyscraper-sized duo to the launch pad for NASA’s next-generation Moon missions.
With the Artemis program, NASA will land the first woman and the first person of color on the Moon and establish sustainable exploration in preparation for missions to Mars. SLS and NASA’s Orion spacecraft, along with the commercial human landing system and the Gateway in orbit around the Moon, are NASA’s backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single mission.
Saturn V, SLS, Falcon Heavy, StarShip 1, Falcon 9 all on launch pad 39-A
If you’ve played it on TV, you can pretty much do it in real life, right? William Shatner seems to think so, because the actor who played the iconic Captain Kirk in the OG Star Trek series and films is about to be beamed up… by a Jeff Bezos rocket. Apparently Shatner has a place on Blue Origin, the very same rocket that Bezos launched into space back in July. If take off goes according to plan, Shatner will be the oldest person to go into space so far.
Believe it or not, William Shatner is a nonagenarian at this point (just like fellow Hollywood star Clint Eastwood), and while going into space is generally a big deal, going into space at 90 is an even bigger deal. Regardless, being the embodiment of Captain Kirk for so long, the actor is a brilliant pick for a space launch. The man is a space legend, yeah, but he’s also super eccentric and is the exact personality I want to see in weird situations that not many people on Earth have experienced. What’s even more than that, is that he really wants to go to space. He’s been very vocal about his desire to see the stars up close and this would be the next step toward that goal.
What a time to be alive: you can wake up at 9 a.m., climb into a rocket that launches you into space, and be back down to Earth in time for lunch. That is, if you have a spare $20 million or are 2 time primetime award winning actor William Shatner. According to TMZ, Shatner’s ticket aboard Blue Origin may be comped, but it’s possible the ticket to space comes with a different type of price.
Apparently the launch and space experience is set to be filmed for a documentary, which may be a big reason for Shatner to be chosen to go on the rocket. Having an actor overwhelmingly known as a spaceship captain actually later launching into space and going where few have boldly gone before, is sure to have a lot of entertainment value.
The Star Trek alum is not the only actor who has been approached for this type of thing. Previously, Kevin Hart was asked to go into space and have his experience filmed. Unlike Shatner, though, Hart’s response was a strong and resounding “Hell no“, and plenty of people would agree with the star that their feet are better left planted on the ground.
William Shatner’s take off is expected to be very soon, as he is set to climb aboard this October. Very similar to Jeff Bezos’ own launch, Shatner’s space experience is going to be very short-lived. The whole thing is expected to only last about 15 minutes. It’s unclear who else will be launching into space with Shatner (it’s unlikely we’ll be lucky enough to see other Star Trek alums), but I personally hope we’ll see some comedy figures for some seriously funny reactions to zero gravity in actual space.
William Shatner is 90-years-old, and he clearly has no qualms about jumping into a rocket headed for space. Even though he will be the oldest person to go to space yet, I wouldn’t be surprised if more older people start stepping up and crossing going to space off their bucket list after he returns.
Shatner won’t technically be an astronaut. The Federal Aviation Administration issued new guidelines right after Bezos’ first flight, changing the rules so only those who “demonstrate activities during flight that were essential to public safety, or contributed to human space flight safety” get their official astronaut wings.
Space shuttle Enterprise in the Shuttle Pavilion at the Intrepid Sea, Air & Space Museum in New York City.
Credit: Image courtesy Intrepid Museum.
On Sept. 17, 1976, NASA rolled out its first space shuttle, named Enterprise, from its manufacturing plant in Palmdale, California. The story of Enterprise officially began on Jan. 5, 1972, when President Richard M. Nixon directed NASA to build the partially reusable space transportation system, stating that “it would revolutionize transportation into near space.” NASA Administrator James C. Fletcher hailed the President’s decision as “an historic step in the nation’s space program,” adding that it would change what humans can accomplish in space. Following two years of construction and assembly, gathered dignitaries who hailed the benefits of the new space transportation system witnessed Enterprise’s premiere roll out. The creator and cast members of the TV series Star Trek also attended the event.
Left: On Jan. 5, 1972, NASA Administrator James C. Fletcher, left, presents President Richard M. Nixon with a model of the proposed space shuttle.
Right: President Gerald R. Ford and Administrator Fletcher during the Sept.8, 1976 White House meeting when the first orbiter was named Enterprise.
On July 26, 1972, NASA awarded the contract to the Space Division of the North American Rockwell Corporation, later known as Rockwell International, of Downey, California, to begin construction. Manufacture of the first components of Orbital Vehicle-101 (OV-101) – the formal designation of the first space shuttle – began on June 4, 1974, at Rockwell’s Downey plant. Construction continued over the next two years, with final assembly of the orbiter taking place at the Rockwell plant in Palmdale, California. As originally conceived, OV-101 would conduct approach and landing tests (ALT) in the atmosphere to verify the vehicle’s aerodynamic characteristics and then be retrofitted to become a space worthy orbiter. But modifying OV-101 proved to be too costly, and following completion of the ALTs, NASA used the first shuttle to conduct additional tests to prepare its sister ships for orbital flights.
Left: At Rockwell International’s Downey, California, plant, during manufacture of the first space shuttle orbiter, workers lower the upper cabin onto the lower forward cabin section in November 1975. Middle: In May 1975, the orbiter’s wings arrived at Rockwell’s Palmdale, California, facility.
Right: In December 1975, workers install the orbiter’s vertical stabilizer at the Palmdale plant.
Left: The first space shuttle orbiter under assembly at Rockwell International’s Palmdale, California, facility in December 1975.
Right: The first space shuttle orbiter nearing completion in July 1976.
NASA originally planned to name OV-101 Constitution to honor the nation’s foundational document, with the public rollout of the vehicle planned for Constitution Day in 1976. Fans of the science fiction TV series Star Trek mounted a determined write-in campaign, before the age of the Internet and social media, to NASA and to President Gerald R. Ford to instead name this first vehicle Enterprise, after the fictional starship made famous by the show. By one account, these fans sent hundreds of thousands of letters. During a Sept. 8 meeting at the White House – coincidentally, the 10th anniversary of the debut of the original TV show on NBC – President Ford advised NASA Administrator Fletcher that he was partial to the name Enterprise, saying, “It is a distinguished name in American naval history, with a long tradition of courage and endurance. It is also a name familiar to millions of faithful followers of the science fiction television program Star Trek. To explore the frontiers of space, there is no better ship than the space shuttle, and no better name for that ship than the Enterprise.”
When the vehicle made its public debut at Rockwell’s Palmdale, California, facility, on Sept. 17, 1976, it bore the name Enterprise. More than 600 invited guests and 185 media representatives attended the ceremony. John F. Yardley, NASA associate administrator for the Office of Space Flight, opened the event and served as master of ceremonies. In his remarks, NASA Administrator Fletcher called the rollout a “very proud moment for the agency,” adding that the new reusable space transportation system will “benefit this nation and all the nations of the world.” He then directed that Enterprise begin the rollout. As Enterprise emerged from the hangar, the Air Force Band of the Golden West from March Air Force Base in Riverside County, California, played Alexander Courage’s Star Trek musical score. Several Star Trek cast members as well as the show’s creator Gene Roddenberry were on hand to witness the historic event, as were the four astronauts who were scheduled to conduct the approach and landing tests with Enterprise – Fred W. Haise, C. Gordon Fullerton, Joe H. Engle, and Richard H. Truly.
Left: NASA Administrator Fletcher, left, accompanied by several cast members and the creator of the TV series Star Trek at Enterprise’s rollout. Noticeably absent actor William Shatner (aka Captain Kirk).
Right: Astronauts C. Gordon Fullerton, left, Fred W. Haise, Joe H. Engle, and Richard H. Truly pose in front of Enterprise on the day of its rollout.
The following day, workers rolled Enterprise out once again, this time for the benefit of the general public and Rockwell International employees. As a comparison with earlier spacecraft, the Apollo 14 Command Module Kitty Hawk was displayed next to Enterprise. More than 35,000 people came to see the new space shuttle.
Left: Space shuttle Enterprise on display for the general public and Rockwell International employees.
Right: The Apollo 14 Command Module Kitty Hawk is visible behind Enterprise’s starboard wingtip.
After additional testing at Palmdale, in January 1977 workers trucked Enterprise 36 miles overland to NASA’s Dryden Flight Research Center, now NASA’s Armstrong Flight Research Center, at Edwards Air Force Base in California, where the space shuttle began preparations for the approach and landing tests. Placed atop the Shuttle Carrier Aircraft, a modified Boeing 747, Enterprise began taxi runs in February, followed by the first captive inactive flight later that month. The first captive active flight that included a crew aboard the shuttle took place in June, and Enterprise made its first independent flight on Aug. 12, 1977, with Haise and Fullerton at the controls. Four additional approach and landing flights were completed by October to complete the test program. Over the next few years, NASA used Enterprise to conduct various tests to prepare its sister ships for space flights, including fit checks at Launch Pad 39A at NASA’s Kennedy Space Center in Florida in 1979.
Piloted by astronauts Fred Haise and Gordon Fullerton, the prototype space shuttle enterprise settles toward the main runway at Edwards Air Force Base on its final Approach and Landing Test flight on Oct. 26, 1977 (NASA photo)
In 2003, the Smithsonian Institution’s National Air and Space Museum displayed Enterprise at its newly-opened Stephen F. Udvar-Hazy Center in Chantilly, Virginia. In 2012, Enterprise was moved to the Intrepid Sea, Air & Space Museum in New York City where it is currently on display.
Editor’s note: Something a little different for today’s Post in the science probe we’re going to be taking a look at the uniform for the US space force this is a prototype and it is not actually yet the uniform that will be distributed to The Guardians as they are known.
Logo of the United States Space Force: A.K.A The Guardians
Some people call them futuristic; others say they’re a new take on the classic double-breasted tunic. But it seems everyone has a reaction to the new Space Force uniforms that the chief of space operations, Gen. John Raymond, unveiled at a conference this week.
To many, the uniforms resemble those worn by officers in the sci-fi TV series Battlestar Galactica from the 2000s. Similar design elements include the jacket’s high collar and its asymmetrical, angled row of buttons.
The Space Force uniform combines a dark blue jacket with gray pants. Its buttons prominently feature the delta shape that the service adopted soon after its creation — and which has frequently been compared to the Starfleet emblem from the venerable Star Trek franchise.
The six buttons symbolize the Space Force’s status as the sixth branch of the U.S. military, Raymond said Tuesday, as two guardians — the name for Space Force service members — modeled the uniform at the Air Force Association’s Air, Space & Cyber Conference at National Harbor, Md.
The U.S. Space Force unveiled prototypes for its new service dress uniforms at this year’s Air, Space & Cyber Conference. Image: Air Force Association
“Every winning team needs a uniform!”
General John Raymond
The uniforms are still in the prototype stage, Raymond said, predicting that they will be tweaked a bit before going into “wear testing” in the coming months. After that, he added, they’ll be rolled out to the force’s guardians.
“We started with the female design and then created the male prototype” for the uniforms, Raymond added.
The newly unveiled uniforms are “service dress” — the military equivalent to a coat and tie and a notch below full, formal or dinner dress. But a commenter on the Space Force subreddit says that for that purpose, “this is way over the top,” suggesting that the uniforms seem too formal and constricting.
The chief of space operations, Gen. John Raymond, stands between two Space Force guardians as the branch unveils prototypes for its new service dress uniforms.
Other commenters took exception to the pants being a different color. And many seemed to agree with a commenter on the Space Force’s Facebook page who posted an image from Battlestar Galactica, saying the new uniform echoes the series. The person also added one of the show’s taglines: “So say we all.”
Raymond also gave an update on how the nascent Space Force is developing. For example, the force is taking over a number of Army and Navy satellite communications operations, including their funding and ongoing missions.
“All told, 15 global units with 319 military and 259 civilian billets [job slots] from the Army and Navy combined will transfer to the Space Force,” the Defense Department stated.
Describing the urgency with which the service is being created, Raymond said that the U.S. “can no longer take space for granted.”
“Space is clearly a warfighting domain, and we’re convinced that if deterrence were to fail, we’re going to have to fight and win the battle for space superiority,” Raymond said. He added, “Let me be clear: We don’t want to fight in space. We want to deter that from happening.”
World Space Week 2021 celebrates “Women in Space”!
Join thousands of participants in over 90 countries celebrating accomplishments and contributions of women to the space sector and sciences.
In 2020, more than 6,500 events were organized in over 60 countries under the ”Women in Space”.
The United Nations General Assembly declared World Space Week in 1999. The celebration of World Space Week is under the guidance of the UN Committee on the Peaceful Uses of Outer Space (COPUOS) and the UN Office for Outer Space Affairs (UNOOSA) based in Vienna, Austria.
Each year, the World Space Week Association (WSWA) selects a theme for the upcoming World Space Week (WSW) to provide a focus of the activities and events that take a place throughout the world, during 4-10 October . The World Space Week 2021 theme is “Women in Space!”
World Space Week, October 4-10, 2021 will celebrate the role of space in bringing the world closer together. The theme is inspired by UNISPACE+50, an historic gathering of world space leaders which will occur in 2021. UNISPACE+50 will promote cooperation between spacefaring and emerging space nations and help space exploration activities become open and inclusive on a global scale.
The growth of World Space Week reflects widespread acceptance of this synchronized time frame to celebrate space, inspire students using space, and promote space programs, policies, and organizations. WSW is celebrated by a network of over 1,000 space-related organizations, the largest such network in the world, according to WSWA.
The Association’s Board each year selects a theme for World Space Week to provide a focus of the activities and events that take a place in over 80 nations during 4-10 October. WSW event organizers are encouraged to incorporate the theme into their activities and promotional materials.
Anyone, from anywhere in the world, can create a World Space Week event. The theme is a guideline for creating events, however, WSWA accepts the registration of any space-related events which start or end from 4 to 10 October as an official World Space Week event.
WSW event organizers are encouraged to incorporate the theme and poster into their activities and promotional materials. To see the history of World Space Week themes, please click here.
How do you celebrate World Space Week? It is much simpler than you may think! Just have a look at these simple steps on How to Organize a World Space Week Event.
FEATURING these International Women Astronauts
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1) Dr. Yi So-Yeon, biotechnologist and the first and only astronaut in South Korea. 🚀🇰🇷👩🚀
2) Dr. Helen Patricia Sharman, a British chemist, the first British astronaut, first privately funded woman to fly in space, and the first woman to visit the Mir space station. 🛰️🇬🇧👩🚀
3) Dr. Claudie Haigneré, a French doctor, politician, and former astronaut, who was the first French Woman in space and the first woman to qualify as a Soyuz Return Commander. 🚀🇫🇷👩🚀
4) Dr. Norah Patten, Aeronautical Engineer, Global Faculty, Bioastronautics Researcher. Likely to be the first Irish Female Astronaut. 🚀🇮🇪👩🚀
5) Major Samantha Cristoforetti, Avid Star Trek fan and former holder of the longest time in orbit by a Female. The Major in the Italian Air Force will be returning to the ISS soon, Samantha also has many instructional videos you can see on YouTube. 🛰️🇮🇹👩🚀
6) Loretta Hidalgo Whitesides is co-creator of Yuri’s Night, and an author on space exploration. She accumulated over five hours of weightless time as a Flight Director for Zero-G Corporation, and plans to travel to space as a “Founder Astronaut” on Virgin Galactic’s SpaceShipTwo. ⭐🇺🇸👩🚀
World Space Week
The Early Days
The World Space Week Association (WSWA) began in 1980 as the coordinator of “Spaceweek,” a celebration of the first Moon landing, each July 16-24. The first celebration in Houston that year was led by Ernie Hillje, Troy Welch, David Koch, and Dennis Stone (picture, left to right). In 1981 they formed “Spaceweek National Headquarters” to organize a nationwide celebration in the United States. By 1999 Spaceweek had spread to over 15 nations. (See “Historical Timeline” below.) It was in 1999 that the UN General Assembly declared “World Space Week” to be held every year from 4 to 10 October. The organization offered to the UN to serve as global coordinator of World Space Week, and helped organize the first such celebration in 2000. Today, the Association continues to build the size and impact of this annual celebration of space, the largest in the world.
World Space Week Themes
Every year the World Space Week Association Board of Directors selects a theme to highlight an aspect of space with broad appeal to humanity. This theme provides guidance to World Space Week participants on the content of their programs. Event holders are encouraged to address the current year’s theme in their events and publicity.
2021 – Women in Space 2020 – Satellites Improve Life 2019 – The Moon: Gateway to the Stars 2018 – Space Unites the World 2017 – Exploring New Worlds In Space 2016 – Remote Sensing – Enabling our Future 2015 – Discovery 2014 – Space: Guiding Your Way 2013 – Exploring Mars – Discovering Earth>/a> 2012 – Space for Human Safety and Security 2011 – 50 Years of Human Spaceflight 2010 – Mysteries of the Cosmos 2009 – Space for Education 2008 – Exploring the Universe 2007 – 50 Years in Space 2006 – Space for Saving Lives 2005 – Discovery and Imagination 2004 – Space for Sustainable Development 2003 – Space: Horizon Beyond Earth 2002 – Space and Daily Life 2001 – Inspiration from Space 2000 – Launching the Space Millennium
To answer this question we must travel back in time.
If you’ve ever gazed at a model of the solar system, you’ve likely noticed that the sun, planets, moons and asteroids sit roughly on the same plane. But why is that?
To answer this question, we have to travel to the very beginning of the solar system, about 4.5 billion years ago.
Back then, the solar system was just a massive, spinning cloud of dust and gas, Nader Haghighipour, an astronomer at the University of Hawaii at Mānoa, told Live Science. That massive cloud measured 12,000 astronomical units (AU) across; 1 AU is the average distance between Earth and the sun, or about 93 million miles (150 million kilometers). That cloud became so big, that even though it was just filled with dust and gas molecules, the cloud itself started to collapse and shrink under its own mass, Haghighipour said.
As the spinning cloud of dust and gas started to collapse, it also flattened. Imagine a pizza maker throwing a spinning slab of dough into the air. As it spins, the dough expands but becomes increasingly thin and flat. That’s what happened to the very early solar system.
Meanwhile, in the center of this ever-flattening cloud, all those gas molecules got squeezed together so much, they heated up, Haghighipour said. Under the immense heat and pressure, hydrogen and helium atoms fused and kick-started a billions-of-years-long nuclear reaction in the form of a baby star: the sun. Over the next 50 million years, the sun continued to grow, collecting gas and dust from its surroundings and burping out waves of intense heat and radiation. Slowly, the growing sun cleared out a doughnut of empty space around it.
Simulations of planet formation tend to give us planets forming in a disk-like configuration, similar to what we observe in our own Solar System.
As the sun grew, the cloud continued to collapse, forming “a disk around the star [that] becomes flatter and flatter and expands and expands with the sun at the center,” Haghighipour said.
Eventually, the cloud became a flat structure called a protoplanetary disk, orbiting the young star. The disk stretched hundreds of AU across and was just one-tenth of that distance thick, Haghighipour said.
For tens of millions of years thereafter, the dust particles in the protoplanetary disk gently swirled around, occasionally knocking into each other. Some even stuck together. And over those millions of years, those particles became millimeter-long grains, and those grains became centimeter-long pebbles, and the pebbles continued to collide and stick together.
The eight planets of the Solar System orbit the Sun in almost an identical plane, known as the Invariable Plane. This is typical of solar systems as we know them so far.
Eventually, most of the material in the protoplanetary disk stuck together to form huge objects. Some of those objects grew so big that gravity shaped them into spherical planets, dwarf planets and moons. Other objects became irregularly shaped, like asteroids, comets and some small moons.
Despite these objects’ different sizes, they stayed more or less on the same plane, where their building materials originated. That’s why, even today, the solar system’s eight planets and other celestial bodies orbit on roughly the same level.
Originally published on Live Science.
Written by JoAnna Wendel
Who is a freelance science writer living in Portland, Oregon. She mainly covers Earth and planetary science but also loves the ocean, invertebrates, lichen and moss. JoAnna’s work has appeared in Eos, Smithsonian Magazine, Knowable Magazine, Popular Science and more. JoAnna is also a science cartoonist and has published comics with Gizmodo, NASA, Science News for Studentsand more.
Of The USS Stephen Hawking Star Trek Fan Association
