Tag Archives: Charon

Did Pluto’s moon Charon harbor an ancient ocean?

As NASA’s New Horizons shuttle zoomed past Pluto, it snapped awesome photos not only of the “ex-planet”, but also of its moons. Now researchers are analyzing those pictures and reporting surprising finds – such as an ancient ocean on Charon, Pluto’s moon.

Too big for its skin?

Pluto’s Moon Charon A close-up of the canyons on Charon, Pluto’s big moon, taken by New Horizons during its close approach to the Pluto system last July. Multiple views taken by New Horizons as it passed by Charon allow stereo measurements of topography, shown in the color-coded version of the image. The scale bar indicates relative elevation.

The side of Pluto’s largest moon viewed by NASA’s passing New Horizons exhibits feature of “pull apart” tectonic faults. Faults are basically discontinuities in large volumes of rock, with significant displacements. The mass of rock can move towards each other, away from each other or slide by each other in a parallel line. Pull apart faults are areas where rocks move away from each other, and they are usually expressed by ridges, scarps and valleys – all of which can be observed on Charon. Some valleys are actually 4 miles (6.5 kilometers) deep, which is extremely impressive when you consider that its entire mean radius is 606 kilometers.

However, Charon can’t have tectonics like Earth has, because it doesn’t have a hot core and mantle that circulates under the crust, so researchers propose a different mechanism. Charon’s outside is primarily water ice. It’s all frozen, but this might have not always been always the case. When Charon was young, this layer was probably kept warmer by heat provided by the decay of radioactive elements, as well as Charon’s own internal heat of formation. It was probably hot enough to melt some of the water, so Charon had a subsurface ocean. But as Charon cooled over time, this ocean would have frozen. When water freezes, it expands, lifting the outer layers and pulling them apart.

This process makes a lot of geological sense, but the entire process must have been extremely violent. Charon exhibits one of the longest systems of chasms in the solar system,  running at least 1,100 miles (about 1,800 kilometers) long and reaching 4.5 miles (7.5 kilometers) deep. By comparison, the Grand Canyon is 277 miles (446 kilometers) long and just over a mile (1.6 kilometers) deep.


Astropicture of the Week: Pluto

We’ve seen Pluto in all its splendor recently thanks to the New Horizons mission that flew by the former planet / currently planetoid, but just when you thought it can’t surprise you anymore… something like this comes along. This is Pluto.


Recently, a paper was published based on the data that New Horizons sent back to Earth, including impressions about Pluto and its moons: Charon, Styx, Nix, Kerberos and Hydra. This is important not only to understand the Pluto system, but it can provide valuable information about our solar system in itself.

“All of the data about Pluto and its moons (even the little bitty moons) and 67P, and the next Kuiper Belt object we go to with New Horizons in a little over three years – all of this will feed into trying to understand how the Solar System formed,” said Prof Bill McKinnon from Washington University in St Louis, Missouri.

Pluto’s Charon reveals colorful and violent past

NASA’s New Horizons shuttle wasn’t only taking mind blowing photos of Pluto, it was also peeking at Pluto’s moons, especially Charon – the largest one. The latest set of images analyzed by NASA researchers revealed quite a busy past, filled with violence and geologic activity.

Charon in Enhanced Color NASA’s New Horizons captured this high-resolution enhanced color view of Charon just before closest approach on July 14, 2015. The image combines blue, red and infrared images taken by the spacecraft’s Ralph/Multispectral Visual Imaging Camera (MVIC); the colors are processed to best highlight the variation of surface properties across Charon. Charon’s color palette is not as diverse as Pluto’s; most striking is the reddish north (top) polar region, informally named Mordor Macula. Charon is 754 miles (1,214 kilometers) across; this image resolves details as small as 1.8 miles (2.9 kilometers).

Charon is the largest and best studied moon of Pluto. It is a very large moon in comparison to its parent body, Pluto, and some astronomers have argued that Charon itself should be considered a dwarf planet like Pluto, and not a moon. nlike Pluto’s surface, which is composed of nitrogen and methane ices, Charon’s surface appears to be dominated by the less volatile water ice. The south polar area is dominated by a very large dark area informally dubbed “Mordor” by the New Horizons team. Aside from Mordor, however, New Horizons imaged very few other impact craters on Charon and found a youthful surface, adding support to the above theory that Charon is geologically active and thus probably differentiated (meaning it has a crust, a mantle and a core).

“We thought the probability of seeing such interesting features on this satellite of a world at the far edge of our solar system was low,” said Ross Beyer, an affiliate of the New Horizons Geology, Geophysics and Imaging (GGI) team from the SETI Institute and NASA Ames Research Center in Mountain View, California, “but I couldn’t be more delighted with what we see.”

For starters, the features are incredibly visible – you can see craters, ridges, and even fractures on its surface, but the most spectacular feature is definitely a huge canyon. The canyon stretches more than 1,000 miles (1,600 kilometers) across the entire face of Charon and likely around onto Charon’s far side, four times larger than the Grand Canyon, indicating a huge geologic upheaval in Charon’s past.

“It looks like the entire crust of Charon has been split open,” said John Spencer, deputy lead for GGI at the Southwest Research Institute in Boulder, Colorado. “With respect to its size relative to Charon, this feature is much like the vast Valles Marineris canyon system on Mars.”

High-resolution images of Charon were taken by the Long Range Reconnaissance Imager on NASA’s New Horizons spacecraft, shortly before closest approach on July 14, 2015, and overlaid with enhanced color from the Ralph/Multispectral Visual Imaging Camera (MVIC). Charon’s cratered uplands at the top are broken by series of canyons, and replaced on the bottom by the rolling plains of the informally named Vulcan Planum. The scene covers Charon’s width of 754 miles (1,214 kilometers) and resolves details as small as 0.5 miles (0.8 kilometers).

They also found that the moon’s southern part has way fewer craters than the northern part. The smoothness of the plains, as well as their grooves and faint ridges, are clear signs of wide-scale resurfacing. This could be the effect of a kind of cold volcanic activity, called cryovolcanism.

“The team is discussing the possibility that an internal water ocean could have frozen long ago, and the resulting volume change could have led to Charon cracking open, allowing water-based lavas to reach the surface at that time,” said Paul Schenk, a New Horizons team member from the Lunar and Planetary Institute in Houston.

Right now, the existence (and extent) of geological features on Charon has taken both astronomers and geologists by surprise, but they couldn’t be more thrilled. The good news is that even more pictures of Charon are currently being sent by New Horizons, and some of them will come in even better resolution. We’ll keep you posted as that happens.

This composite of enhanced color images of Pluto (lower right) and Charon (upper left), was taken by NASA’s New Horizons spacecraft as it passed through the Pluto system on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties, and to highlight the similarity between Charon’s polar red terrain and Pluto’s equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their true separation is not to scale. The image combines blue, red and infrared images taken by the spacecraft’s Ralph/Multispectral Visual Imaging Camera (MVIC).

“I predict Charon’s story will become even more amazing!” said mission Project Scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

They’re here: NASA’s best up-close and personal photos of Pluto

New close-ups of Pluto’s surface have been revealed by NASA today, revealing a stunning variety of features on the frozen planetoid. A range of majestic mountains surrounds seemingly endless plains, and now, we get to see them all with unprecedented quality.

pluto new horizons

This synthetic perspective view of Pluto, based on the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft, shows what you would see if you were approximately 1,100 miles (1,800 kilometers) above Pluto’s equatorial area. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

It’s so spectacular that even NASA’s investigators were surprised.

“Pluto is showing us a diversity of landforms and complexity of processes that rival anything we’ve seen in the solar system,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI), Boulder, Colorado. “If an artist had painted this Pluto before our flyby, I probably would have called it over the top — but that’s what is actually there.”

The New Horizons space probe was the first space probe to investigate Pluto up-close, but it already passed by the planetoid in July, so why are we seeing these photos just now? Well, New Horizons took a massive amount of data and it will take about a year before NASA is able to download all the data – and it will also take a while to analyze them. In the meantime, we have to settle for these gorgeous pics.

pluto new horizons

Mosaic of high-resolution images of Pluto, sent back from NASA’s New Horizons spacecraft from Sept. 5 to 7, 2015. The image is dominated by the informally-named icy plain Sputnik Planum, the smooth, bright region across the center. This image also features a tremendous variety of other landscapes surrounding Sputnik. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

But aside from being stunning, the photos highlight the surprising diversity of features on Pluto. Possible dunes, nitrogen ice flows that apparently oozed out of mountainous regions onto plains, and even networks of valleys that may have been carved by material flowing over Pluto’s surface were spotted.

“The surface of Pluto is every bit as complex as that of Mars,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging (GGI) team at NASA’s Ames Research Center in Moffett Field, California. “The randomly jumbled mountains might be huge blocks of hard water ice floating within a vast, denser, softer deposit of frozen nitrogen within the region informally named Sputnik Planum.”

pluto new horizons

In the center of this 300-mile (470-kilometer) wide image of Pluto from NASA’s New Horizons spacecraft is a large region of jumbled, broken terrain on the northwestern edge of the vast, icy plain informally called Sputnik Planum, to the right. The smallest visible features are 0.5 miles (0.8 kilometers) in size. This image was taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Old, heavily cratered terrain sits next to young, pristine fields. But the most surprising things are the dunes (yet unconfirmed).

“Seeing dunes on Pluto — if that is what they are — would be completely wild, because Pluto’s atmosphere today is so thin,” said William B. McKinnon, a GGI deputy lead from Washington University, St. Louis. “Either Pluto had a thicker atmosphere in the past, or some process we haven’t figured out is at work. It’s a head-scratcher.”

The images are so detailed that you can actually do (large scale) geologic studies on them – which in itself is amazing. Who would have thought, a few decades ago, that we’ll be able to study the geology of something 3 billion kilometers away?

“This bonus twilight view is a wonderful gift that Pluto has handed to us,” said John Spencer, a GGI deputy lead from SwRI. “Now we can study geology in terrain that we never expected to see.”

pluto new horizons

This 220-mile (350-kilometer) wide view of Pluto from NASA’s New Horizons spacecraft illustrates the incredible diversity of surface reflectivities and geological landforms on the dwarf planet. The image includes dark, ancient heavily cratered terrain; bright, smooth geologically young terrain; assembled masses of mountains; and an enigmatic field of dark, aligned ridges that resemble dunes; its origin is under debate. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Discoveries aren’t limited to Pluto’s surface – New Horizons also snapped a few images of Pluto’s moons Charon, Nix, and Hydra, which will be released on Friday.

This image of Pluto’s largest moon Charon, taken by NASA’s New Horizons spacecraft 10 hours before its closest approach to Pluto on July 14, 2015 from a distance of 290,000 miles (470,000 kilometers. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Two different versions of an image of Pluto’s haze layers, taken by New Horizons as it looked back at Pluto’s dark side nearly 16 hours after close approach, from a distance of 480,000 miles (770,000 kilometers), at a phase angle of 166 degrees. Pluto’s north is at the top, and the sun illuminates Pluto from the upper right. These images are much higher quality than the digitally compressed images of Pluto’s haze downlinked and released shortly after the July 14 encounter, and allow many new details to be seen. The left version has had only minor processing, while the right version has been specially processed to reveal a large number of discrete haze layers in the atmosphere. In the left version, faint surface details on the narrow sunlit crescent are seen through the haze in the upper right of Pluto’s disk, and subtle parallel streaks in the haze may be crepuscular rays- shadows cast on the haze by topography such as mountain ranges on Pluto, similar to the rays sometimes seen in the sky after the sun sets behind mountains on Earth. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute


Pluto had its moment – now Charon, Pluto’s Moon is in the spotlight

OK, we all know New Horizons zoomed past Pluto, took some breathtaking pictures and then called back home to tell us everything’s fine. But let’s switch our attention a bit and focus on Charon – Pluto’s Moon that’s just as mysterious as its name implies.

Image via NASA.

Charon is the largest of the five known moons of the dwarf planet Pluto, at about 11% of the mass of Pluto. It was named after the ferryman in Greek mythology who would take people’s souls to Hades. Now, as NASA is receiving more and more data taken by the New Horizons, we’re getting the chance to look at more and more detailed pictures of Charon; one of them in particular has sparked researchers’ interest.

The latest sliver shows a 200-mile-long portion of Charon that shows some striking geological features: specifically, we see a deep depression with a high mountain rising out of it. It’s like a geological castle.

“The most intriguing feature is a large mountain sitting in a moat,” Jeff Moore, who leads New Horizons’ Geology, Geophysics and Imaging team, said in a statement. “This is a feature that has geologists stunned and stumped.”

Charon is also pummeled with impact craters, something which can’t be said about Pluto. Actually, let’s go back to Pluto for a second. The presence of mountains on the dwarf planet, along with the absence of impact craters seems to suggests active uplift phenomenon, which is extremely interesting, because there’s no apparent mechanism driving it. Oh, and whatever may drive it, Charon doesn’t have it, so the mystery deepens.

But this doesn’t mean that Charon isn’t active geologically. A previous image has already revealed a large smooth region in Charon’s southern hemisphere suggesting the contrary.

NASA plans to release even more high-resolution images of Charon’s surface in the coming days.

New Horizons and Pluto: Everything You Wanted to Know

Speeding at 14 km per second, NASA’s New Horizons shuttle went past Pluto, hurdling towards the edge of the Solar System. But regardless of what happens, New Horizons’ flyby of the dwarf planet will remained firmly anchored in the history of space exploration.

This is the best photo of Pluto we have. Yes, if you’re wondering, this is true color. Thank you, NASA!

“We have completed the initial reconnaissance of the Solar System, an endeavour started under President Kennedy more than 50 years ago and continuing to today under President Obama,” said the mission’s chief scientist, Alan Stern. “It’s really historic what the US has done, and the New Horizons team is really proud to have been able to run that anchor leg and make this accomplishment.”

As so many scientists have put it: this truly is space exploration. This is going past to the boundaries and past, reaching the very edges of our Solar System, just 112 years after the first plane took off the ground. Nasa’s science chief, John Grunsfeld, said:

“This is true exploration… that view is just the first of many rewards the team will get. Pluto is an extraordinarily complex and interesting world.”

So, we got a chance to get a good look at Pluto, and the tiny former planet is definitely an interesting and active place. It has an apparently active geology, a climate, and almost certainly, many secrets awaiting to be uncovered. Dr. Stern adds:

“On the surface we see a history of impacts, we see a history of surface activity in terms of some features we might be able to interpret as tectonic – indicating internal activity on the planet at some point in its past, and maybe even in its present. This is clearly a world where geology and atmosphere – climatology – play a role. Pluto has strong atmospheric cycles. It snows on the surface. These snows sublimate – (and) go back into the atmosphere – every 248-year orbit.”

The New Horizons team celebrates closest approach.

Just because Pluto isn’t a planet anymore, doesn’t make it a less interesting place. While we won’t go into the debate of whether or not Pluto is or should be considered a planet, it’s worth noting that there’s quite a significant generation gap here: people who learned the planets in recent years likely won’t consider it a planet, while many of us still do. In fact,  the head of NASA, Charles Bolden, still considers it to be a planet. He also praised the entire New Horizons project:

“We’re calling Pluto a planet, technically it’s a dwarf planet. I call it a planet, but I’m not the rule maker. We wanted to demonstrate that we could navigate the last known planet in our Solar System. That is an incredible technological achievement.” He was also surprised to see just how active and diverse Pluto is. Mr Bolden added: “ I expected to see some cold, grey icy planet. It has reddish tint, not unlike Mars. That’s fascinating. We continue to be mesmerised by this incredible planet and its moons.”

Measurements sent back by New Horizons as it came close to Pluto showed that the dwarf planet was 20-30 kilometers larger than previously thought, with a radius of 736 miles – which makes it larger than Eris, a body discovered in 2005. The fact that Pluto was smaller than Eris was one of the strongest arguments for reclassifying Pluto as a minor planet in 2006. He’s also not the only one excited to learn more about Pluto.

Pluto’s size relative to Earth (also presented: Charon, Pluto’s Moon)

“Maybe we need to reconsider its status again,” said Dr Daniel Brown, an astronomy expert at Nottingham Trent University. “What once was a planet and was demoted to a dwarf planet, obscure and without any clear images of the surface, will now be explored to great depth.”

British astronomer Brendan Owens, from the Greenwich Royal Observatory in London echoed the same thoughts:

“This is really unexplored territory. The images of Pluto we got previously have been only a few pixels across, just showing areas of light and dark on this world. Now we’re getting up close and personal, something that has never been done before. This whole region is hard for astronomers to explore because we rely on light, and at that distance so little sunlight falls on these objects that you have very little data to work with. Learning about the composition of Pluto may give us more of a handle on the make-up of the solar system.”

So what’s next for New Horizons? Well, after departing from Pluto, it will start exploring ‘The Third Zone’ also known as the mysterious Kuiper Belt – a region of the Solar System beyond the planets, that’s basically a bunch of uncharted debris left over from the solar system’s formation 4.56 billion years ago. The probe is still adequately fueled, so it can keep going until the Mid-2030s and keep sending valuable data back to Earth.

After that, it will leave the solar system.

“Over the next 20 years it could operate and return scientific data, from a Kuiper Belt flyby and then we have a chance to go further out of the heliosphere (Solar System) and potentially cross the interstellar boundary and sample interstellar space,” said Dr Stern.

As it turns out, NASA’s researchers made accurate predictions regarding Pluto.

If you still have questions, scientists working at the New Horizons mission were answering questions at Reddit. Here are some of the most interesting ones:

What is the most surprising thing you’ve discovered about Pluto since the mission began?

Charon’s dark pole surprised us quite a bit. We expected Charon’s surface to be mostly uniform and featureless.

What is next for New Horizons?
What do we hope to learn about Pluto?
What other information/pictures/data will New Horizons be sending back?
What has your day been like and what does it feel like to be part of the team?

1.Next is all of the data download. It will take ~16 months to download the amazing data.
2.We hope to learn about Pluto and its five known moons. The atmosphere, the geology, the composition of the rocks, and much much more.
3.New Horizons has seven instruments – ALICE, LORRI, PEPSSI, RALPH, REX, SDC, SWAP, so lots of data will be coming down in addition to the images you have seen already.
4.Today has been great. We all gathered and counted down to the closest approach. I can only imagine how exciting tonight will be when NH phones home.

The latest images suggest Pluto’s surface is much newer than Charon’s, even though the dwarf planet and it’s moon are the same age. Are there any theories in the works about the resurfacing process and it’s cause?

There are two likely reasons, but forthcoming New Horizons’ data will hopefully let us refine these or figure out a better reason. One is that Pluto is larger than Charon, so it can retain more heat and have active geology longer. Another is that Pluto has a tenuous atmosphere, and during the 248-year orbit around the sun, the atmosphere sublimates from one area in sun and is deposited in another in darkness, and then this reverses half-way through the orbit. This process is very slow, relatively speaking, but so is cratering.

Will we see detailed photos of Pluto’s moons in near future too?

Charon, yes. Hydra, yes (tomorrow or Thursday!). Nix, perhaps, but not Styx nor Kerberos.

Pluto’s moons resonate in chaos

With NASA’s New Horizons shuttle basically knocking on Pluto’s door, Mark Showalter and Douglas Hamilton present new theories on Pluto’s moons and make predictions about what New Horizons will observe. They propose complex interactions and an intricate “dance” of Pluto’s moons – a miniature version of our solar system.

The Pluto system: Pluto, Charon, Nix, Hydra, Kerberos, and Styx, taken by the Hubble Space Telescope in July 2012.

The Pluto system: Pluto, Charon, Nix, Hydra, Kerberos, and Styx, taken by the Hubble Space Telescope in July 2012.

Despite not being considered a planet anymore, Pluto is still one of the more interesting places in our solar system. NASA launched the New Horizons probe particularly to study it and its moons in 2006. Now, after 9 years, after going through most of our solar system, after 189,916 km (118,008 mi), the probe is approaching its destination. It already took some spectacular close-range photos of Pluto which astronomers are already analyzing, but it’s preparing for more: for the first time, humanity will be able to directly study Pluto’s interactions with its moons (we don’t even know for sure how many moons Pluto has).

“If you polled my science team, I’m quite sure that the majority would be surprised not to find more moons,” says Alan Stern, principal investigator for the New Horizons mission. “The question is are we going to find 2, or 10 or 20? I wouldn’t put my bets on zero.”

But before that happens, scientists are already coming up with theories – Showalter and Hamilton calculated the the orbits of the four smaller moons and turned up some surprises.

Pluto has five known moons: Charon (the largest, with a diameter just over half that of Pluto), Nix, Hydra, Kerberos, and Styx. For starters, they propose that Nix is rotating chaotically, something that you can rarely say about a celestial body.

“It’s not just a little bit chaotic,” Dr. Showalter said. “Nix can flip its entire pole. It could actually be possible to spend a day on Nix in which the sun rises in the east and sets in the north. It is almost random-looking in the way it rotates.”

Furthermore, Pluto’s four small moons — Styx, Nix, Kerberos and Hydra —follow near-circular, near-equatorial orbits around the central ‘binary planet’ comprising Pluto and its large moon, Charon. But it gets even better: although with less certainty, they believe that Styx and Kerberos are also behaving chaotically.

Image via The Planets.

“It’s just that we haven’t been able to measure them well enough to see it yet,” he said.

Of course, Hydra, the farthest known moon of Pluto, couldn’t miss the party. Although not so chaotically, it too seems to exhibit a tumbling motion.

But there is some logic in all this chaos. Styx, Nix and Hydra are tied together by a three-body resonance, so any chaotic movement exhibited by one of them will spread the chaos further to the others. Astronomers believe that within these interactions lie the key to understanding how the Pluto system took shape.

“This is not random chance,” Dr. Showalter said. “There is definitely something about the nature of these near relationships that is a clue about how this system formed and evolved.”

They came up with these conclusion by analyzing images taken between 2002 and 2005, which of course, provide nowhere near the resolution and clarity that New Horizons can. So the good news is that we won’t have to wait much longer before we can get a better view of what’s actually happening at the edge of our solar system.

Journal Reference: M. R. Showalter & D. P. Hamilton. Resonant interactions and chaotic rotation of Pluto’s small moons. Nature 522, 45–49 (04 June 2015) doi:10.1038/nature14469