How Many Moons Does Mars Have?

Many of the planets in our Solar System have a system of moons. But among the rocky planets that make up the inner Solar System, having moons is a privilege enjoyed only by two planets: Earth and Mars. And for these two planets, it is a rather limited privilege compared to gas giants like Jupiter and Saturn which each have several dozen moons.

Whereas Earth has only one satellite (aka. the Moon), Mars has two small moons in orbit around it: Phobos and Deimos. And whereas the vast majority of moons in our Solar System are large enough to become round spheres similar to our own Moon, Phobos and Deimos are asteroid-sized and misshapen in appearance.

Continue reading “How Many Moons Does Mars Have?”

Best Space Photos Of 2014 Bring You Across The Solar System

Feel like visiting a dwarf planet today? How about a comet or the planet Mars? Luckily for us, there are sentinels across the Solar System bringing us incredible images, allowing us to browse the photos and follow in the footsteps of these machines. And yes, there are even a few lucky humans taking pictures above Earth as well.

Below — not necessarily in any order — are some of the best space photos of 2014. You’ll catch glimpses of Pluto and Ceres (big destinations of 2015) and of course Comet 67P/Churyumov–Gerasimenko (for a mission that began close-up operations in 2014 and will continue next year.) Enjoy!

The Philae that could! The lander photographed during its descent by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team/
The Philae that could! The lander photographed during its descent by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team/

The Aurora Borealis seen from the International Space Station on June 28, 2014, taken by astronaut Reid Wiseman. Credit: Reid Wiseman/NASA.
The Aurora Borealis seen from the International Space Station on June 28, 2014, taken by astronaut Reid Wiseman. Credit: Reid Wiseman/NASA.

NASA's Mars Curiosity Rover captures a selfie to mark a full Martian year -- 687 Earth days -- spent exploring the Red Planet.  Curiosity Self-Portrait was taken at the  'Windjana' Drilling Site in April and May 2014 using the Mars Hand Lens Imager (MAHLI) camera at the end of the roboic arm.  Credit: NASA/JPL-Caltech/MSSS
NASA’s Mars Curiosity Rover captures a selfie to mark a full Martian year — 687 Earth days — spent exploring the Red Planet. Curiosity Self-Portrait was taken at the ‘Windjana’ Drilling Site in April and May 2014 using the Mars Hand Lens Imager (MAHLI) camera at the end of the roboic arm. Credit: NASA/JPL-Caltech/MSSS

This global map of Dione, a moon of Saturn, shows dark red in the trailing hemisphere, which is due to radiation and charged particles from Saturn's intense magnetic environment. Credit: NASA/JPL/Space Science Institute
This global map of Dione, a moon of Saturn, shows dark red in the trailing hemisphere, which is due to radiation and charged particles from Saturn’s intense magnetic environment. Credit: NASA/JPL/Space Science Institute

Comet Siding Spring shines in ultraviolet in this image obtained by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. Credit: Laboratory for Atmospheric and Space Physics/University of Colorado; NASA
Comet Siding Spring shines in ultraviolet in this image obtained by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. Credit: Laboratory for Atmospheric and Space Physics/University of Colorado; NASA

This "movie" of Pluto and its largest moon, Charon b yNASA's New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies - resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto's surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
This “movie” of Pluto and its largest moon, Charon b yNASA’s New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies – resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The Mars Reconnaissance Orbiter took this image of a "circular feature" estimated to be 1.2 miles (2 kilometers) in diameter. Picture released in December 2014. Credit: NASA/JPL-Caltech/University of Arizona
The Mars Reconnaissance Orbiter took this image of a “circular feature” estimated to be 1.2 miles (2 kilometers) in diameter. Picture released in December 2014. Credit: NASA/JPL-Caltech/University of Arizona

Jets of gas and dust are seen escaping comet 67P/C-G on September 26 in this four-image mosaic. Click to enlarge. Credit: ESA/Rosetta/NAVCAM
Jets of gas and dust are seen escaping comet 67P/C-G on September 26 in this four-image mosaic. Click to enlarge. Credit: ESA/Rosetta/NAVCAM

Ceres as seen from the Earth-based Hubble Space Telescope in 2004 (left) and with the Dawn spacecraft in 2014 as it approached the dwarf planet. Hubble Credit: NASA, ESA, J. Parker (Southwest Research Institute), P. Thomas (Cornell University), L. McFadden (University of Maryland, College Park), and M. Mutchler and Z. Levay (STScI). Dawn Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. Photo Combination: Elizabeth Howell
Ceres as seen from the Earth-based Hubble Space Telescope in 2004 (left) and with the Dawn spacecraft in 2014 as it approached the dwarf planet. Hubble Credit: NASA, ESA, J. Parker (Southwest Research Institute), P. Thomas (Cornell University), L. McFadden (University of Maryland, College Park), and M. Mutchler and Z. Levay (STScI). Dawn Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. Photo Combination: Elizabeth Howell

New Map Shows ‘Marsquakes’ Shook Wet Valles Marineris Sand, NASA Says

Mars today is a planet that appears to be mostly shaped by wind, but that wasn’t always the case. A new map adds information to the hypothesis that “marsquakes” affected at least a part of the planet’s vast canyon, Valles Marineris, while the area contained spring-filled lakes.

When the damp sand got shaken up, it deposited itself in hills. NASA says the new map, based on observations from the Mars Reconnaissance Orbiter (which you can see below), adds credence to the theory that it was water that made these deposits.

“The conditions under which sedimentary deposits in it formed have been an open issue for decades,” NASA wrote in a press release. “Possibilities proposed have included accumulation in lakebeds, volcanic eruptions under glaciers within the canyons, and accumulation of wind-blown sand and dust.”

The map you see below was created by the U.S. Geological Survey, which has more extensive information on the findings at this website. The observations also produced a suite of research in recent years, such as this 2009 paper led by Scott Murchie at the Johns Hopkins University Applied Research Laboratory.

Part of a map of Candor Chasma (part of Mars' Valles Marineris) based on observations from the Mars Reconnaissance Orbiter. Green is knobby terrain, pink is lobate deposits (ridged material) and blue "stair-stepped morphology" of hills and mesas. Credit: U.S. Geological Survey
Part of a map of Candor Chasma (part of Mars’ Valles Marineris) based on observations from the Mars Reconnaissance Orbiter. Green is knobby terrain, pink is lobate deposits (ridged material) and blue “stair-stepped morphology” of hills and mesas. Credit: U.S. Geological Survey

A Martian Blue Snake, Brought To You By Canadians And A Spacecraft

Here’s the awesome thing about space and social media: in some cases, you can often follow along with a mission almost as soon as the images come to Earth. A group of Canadians is taking that to the next level this month as they take control of the 211th imaging cycle of a powerful camera on the Mars Reconnaissance Orbiter.

While some images need to be kept back for science investigations, the team is sharing several pictures a day on Twitter and on Facebook portraying the views they saw coming back from the High Resolution Imaging Science Experiment (HiRISE) camera. The results are astounding, as you can see in the images below.

“It’s mind-blowing to realize that when the team, myself included, first look at the images, we are likely the first people on Earth to lay eyes upon a portion of the Martian surface that may have not been imaged before at such high resolution,” stated research lead Livio Tornabene, who is part of Western University’s center for planetary science and exploration.

The team will capture up to 150 images between Nov. 30 and Dec. 12, and already have released close to two dozen to the public. Some of the best are below.

Bizarre Mars: Did Lava Bubbles Wrinkle This Giant Circle?

NASA is puzzled by this “enigmatic landform” caught on camera by one of its Mars orbiters, but looking around the region provides some possible clues. This 1.2-mile (2-kilometer) feature is surrounded by relatively young lava flows, so they suspect that it could be some kind of volcanism in the Athabasca area that created this rippled surface.

“Perhaps lava has intruded underneath this mound and pushed it up from beneath. It looks as if material is missing from the mound, so it is also possible that there was a significant amount of ice in the mound that was driven out by the heat of the lava,” NASA wrote in an update on Thursday (Dec. 4).

“There are an array of features like this in the region that continue to puzzle scientists. We hope that close inspection of this … image, and others around it, will provide some clues regarding its formation.”

The picture was captured by the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE), a University of Arizona payload which has released a whole slew of intriguing pictures lately. We’ve collected a sample of them below.

These transverse aeolian ridges seen by the Mars Reconnaissance Orbiter are caused by wind, but scientists are unsure why this image (released in December 2014) shows two wavelengths of ripples. Credit: NASA/JPL-Caltech/University of Arizona
These transverse aeolian ridges seen by the Mars Reconnaissance Orbiter are caused by wind, but scientists are unsure why this image (released in December 2014) shows two wavelengths of ripples. Credit: NASA/JPL-Caltech/University of Arizona

This area south of Coprates Chasma is an example of sulfate and clay deposits on Mars, showing water once flowed readily in this region. Why the water evaporated from the Red Planet is one question scientists are hoping to answer with missions such as the Mars Reconnaissance Orbiter, which took this image (released in December 2014). Credit: NASA/JPL-Caltech/University of Arizona
This area south of Coprates Chasma is an example of sulfate and clay deposits on Mars, showing water once flowed readily in this region. Why the water evaporated from the Red Planet is one question scientists are hoping to answer with missions such as the Mars Reconnaissance Orbiter, which took this image (released in December 2014). Credit: NASA/JPL-Caltech/University of Arizona

Arabia Terra, one of the dustiest regions on Mars, is filled with dunes such as this one captured by the Mars Reconnaissance Orbiter and released in December 2014. Credit: NASA/JPL/University of Arizona
Arabia Terra, one of the dustiest regions on Mars, is filled with dunes such as this one captured by the Mars Reconnaissance Orbiter and released in December 2014. Credit: NASA/JPL/University of Arizona

Mars Needs You! Help Scientists Track Spring Thaw On Red Planet

We’ve been watching Mars with spacecraft for about 50 years, but there’s still so little we know about the Red Planet. Take this sequence of images in this post recently taken by a powerful camera on NASA’s Mars Reconnaissance Orbiter. Spring arrives in the southern hemisphere and produces a bunch of mysteries, such as gray-blue streaks you can see in a picture below.

That’s where citizen scientists can come in, according to a recent post for the University of Arizona’s High Resolution Imaging Science Experiment (HiRISE) camera that took these pictures. They’re asking people with a little spare time to sign up for Planet Four (a Zooniverse project) to look at mysterious Mars features. With amateurs and professionals working together, maybe we’ll learn more about these strange changes you see below.

On Aug. 20, 2014, Martian dust mounds are on top of the araneiforms in 'Inca City', as well as dark areas on the terrain showing where the ice cap in the southern hemisphere burst and sent gas and dust into the surroundings. Fans in the area are pointing in multiple directions, showing how the wind has changed. Image taken by the Mars Reconnaissance Orbiter's HiRISE camera. Credit: NASA/JPL/University of Arizona
On Aug. 20, 2014, Martian dust mounds are on top of the araneiforms in ‘Inca City’, as well as dark areas on the terrain showing where the ice cap in the southern hemisphere burst and sent gas and dust into the surroundings. Fans in the area are pointing in multiple directions, showing how the wind has changed. Image taken by the Mars Reconnaissance Orbiter’s HiRISE camera. Credit: NASA/JPL/University of Arizona

On Aug. 25, 2014, more fans and blotches appear on the Martian landscape around "Inca City", a location in the southern polar region, as the ice bursts in the springtime sun. Image obtained by the Mars Reconnaissance Orbiter's HiRISE camera. Credit: NASA/JPL/University of Arizona
On Aug. 25, 2014, more fans and blotches appear on the Martian landscape around “Inca City”, a location in the southern polar region, as the ice bursts in the springtime sun. Image obtained by the Mars Reconnaissance Orbiter’s HiRISE camera. Credit: NASA/JPL/University of Arizona

As of Sept. 6, 2014, fans in "Inca City" in the Martian southern hemisphere are now blue-gray. Why this color appears in the spring is unknown. It could be because of particles falling into ice underneath, or gas bursting from the ice condensing and falling as frost. It could even be a combination of the two. Image taken by the Mars Reconnaissance Orbiter's HiRISE orbiter. Credit: NASA/JPL/University of Arizona
As of Sept. 6, 2014, fans in “Inca City” in the Martian southern hemisphere are now blue-gray. Why this color appears in the spring is unknown. It could be because of particles falling into ice underneath, or gas bursting from the ice condensing and falling as frost. It could even be a combination of the two. Image taken by the Mars Reconnaissance Orbiter’s HiRISE orbiter. Credit: NASA/JPL/University of Arizona

As spring takes hold in the southern polar region of Mars on Sept. 27, 2014, cracks are now developing in the ice at "Inca City" with multiple new dust fans appearing. Cracks develop when the ice does not have a path to easily rupture and release gas. Picture taken by the Mars Reconnaissance Orbiter's HiRISE camera. Credit: NASA/JPL/University of Arizona
As spring takes hold in the southern polar region of Mars on Sept. 27, 2014, cracks are now developing in the ice at “Inca City” with multiple new dust fans appearing. Cracks develop when the ice does not have a path to easily rupture and release gas. Picture taken by the Mars Reconnaissance Orbiter’s HiRISE camera. Credit: NASA/JPL/University of Arizona

MRO Spies Tiny, Bright Nucleus During Comet Flyby of Mars

Not to be outdone by the feisty Opportunity Rover, the HiRISE camera on NASA’s Mars Reconnaissance Orbiter (MRO) turned in its homework this evening with a fine image of comet C/2013 Siding Spring taken during closest approach on October 19. 

The highest-resolution images were acquired by HiRISE at the minimum distance of 85,750 miles (138,000 km). The image has a scale of 453 feet (138-m) per pixel.

The top set of photos uses the full dynamic range of the camera to accurately depict brightness and detail in the nuclear region and inner coma. Prior to its arrival near Mars astronomers estimated the nucleus or comet’s core diameter at around 0.6 mile (1 km). Based on these images, where the brightest feature is only 2-3 pixels across, its true size is shy of 1/3 mile or 0.5 km. The bottom photos overexpose the comet’s innards but reveal an extended coma and the beginning of a tail extending to the right.

Annotated photo of Comet Siding Spring taken by the Opportunity Rover on October 19 when near closest approach. Credit: NASA/JPL-Caltech/Cornell Univ./ASU/TAMU
Annotated photo of Comet Siding Spring taken by the Opportunity Rover on October 19 when near closest approach. Credit: NASA/JPL-Caltech/Cornell Univ./ASU/TAMU

To photograph a fast-moving target from orbit, engineers at Lockheed-Martin in Denver precisely pointed and slewed the spacecraft based on comet position calculations by engineers at JPL. To make sure they knew exactly where the comet was, the team photographed the comet 12 days in advance when it was barely bright enough to register above the detector’s noise level. To their surprise, it was not exactly where orbital calculations had predicted it to be. Using the new positions, MRO succeeded in locking onto the comet during the flyby. Without this “double check” its cameras may have missed seeing Siding Spring altogether!

Meanwhile, the Jet Propulsion Lab has released an annotated image showing the stars around the comet in the photo taken by NASA’s Opportunity Rover during closest approach. From Mars’ perspective the comet passed near Alpha Ceti in the constellation Cetus, but here on Earth we see it in southern Ophiuchus not far from Sagittarius.

Comet Siding Spring continues on its way today past the planet Mars in this photo taken on October 20. Copyright: Rolando Ligustri
Comet Siding Spring continues on its way today past the planet Mars in this photo taken on October 20. Copyright: Rolando Ligustri

“It’s excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the instruments we’re using to study Mars,” said Opportunity science team member Mark Lemmon of Texas A&M University, who coordinated the camera pointing. “The views from Mars rovers, in particular, give us a human perspective, because they are about as sensitive to light as our eyes would be.”

After seeing photos from both Earth and Mars I swear I’m that close to picturing this comet in 3D in my mind’s eye. NASA engineers and scientists deserve a huge thanks for their amazing and successful effort to turn rovers and spacecraft, intended for other purposes, into comet observatories in a pinch and then deliver results within 24 hours. Nice work!

Sandy Ridges Pose A Mystery For Future Martian Beach Vacations

What are these thick dune-like features on Mars, and how were they formed? Scientists are still trying to puzzle out these ridges, which you can see above in a more tropical region of the Red Planet called Iapygia, which is south of Syrtis Major. The thick ridges were captured from orbit by the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE), and we’ve included some more intriguing pictures below the jump.

“Called transverse aeolian ridges, or TARs, the features stand up to 6 meters tall and are spaced a few tens of meters apart. They are typically oriented transverse to modern day wind directions, and often found in channels and crater interiors,” read an update on the University of Arizona’s HiRISE blog.

“The physical process that produces these features is still mysterious. Most TARs display no evidence of internal structure, so it is difficult to discern exactly how they were formed.”

A wider view of the Iapygia region on Mars, where transverse aeolian ridges (TARs) -- dune-like features -- were spotted in 2014. PIcture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona
A wider view of the Iapygia region on Mars, where transverse aeolian ridges (TARs) — dune-like features — were spotted in 2014. PIcture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

This picture from the NASA spacecraft was taken in Iapygia, which is south of Syrtis Major. While scientists say these look similar to TARs in other parts of the Red Planet, the features have layers on the northwest faces and a paucity on the southern side.

Scientists suggest it’s because these TARs may have had wedge-shaped layers, which hints that they would have gotten taller as material was added to the ridges. They hope to do further studies to learn more about how TARs formed in other regions on Mars.

We’ve included other recent releases from the HiRISE catalog below, so enjoy the Martian vistas!

An image of Eridania Basin, a southern region of Mars that once could been a lake or inland sea. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona
An image of Eridania Basin, a southern region of Mars that once could been a lake or inland sea. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

Scientists are still puzzling out the nature and formation of these light-toned deposits in the old Vinogradov Crater on Mars. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona
Scientists are still puzzling out the nature and formation of these light-toned deposits in the old Vinogradov Crater on Mars. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

Older lava flows in Daedalia Planum on Mars. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona
Older lava flows in Daedalia Planum on Mars. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

The Latest Pictures From Mars Make Us Feel Spoiled

Don’t you love it when close-up pictures come beaming to your computer from another planet? Below are some of the latest images from Mars taken by the High Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter.

And by the way, there’s a way for you to request where HiRISE will be pointing next.

All you need to go to this page (called HiWish) and leave a suggestion for where you’d like the spacecraft to look. For some tips on what to do:

The general consensus seems to be picking a spot that is not over-popular, and trying to find a spot that HiRISE has not looked at before or very frequently. Best of luck!

To see more HiRISE images from the latest release, check out this webpage.

A HiRISE image called "Nili Patera." Credit: NASA/JPL/University of Arizona
A HiRISE image called “Nili Patera.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "scalloped surface in Utopia region." Credit: NASA/JPL/University of Arizona
A HiRISE image called “scalloped surface in Utopia region.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "gullied crater wall." Credit: NASA/JPL/University of Arizona
A HiRISE image called “gullied crater wall.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "active dune gullies in Kaiser crater." Credit: NASA/JPL/University of Arizona
A HiRISE image called “active dune gullies in Kaiser crater.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "dark-capped plain and hills in western Arabia region intercrater terrain." Credit: NASA/JPL/University of Arizona
A HiRISE image called “dark-capped plain and hills in western Arabia region intercrater terrain.” Credit: NASA/JPL/University of Arizona

Water Or Not? Fresh Martian Trenches Primarily Due To Carbon Dioxide Freezes, Study Says

Mars Reconnaissance Orbiter

Does liquid water currently flow on the surface of Mars? Fresh-looking trenches on the Red Planet have come under a lot of scrutiny, including a 2010 study concluding that 18 dune gullies were primarily formed by carbon dioxide freezing.

A new study looking at several more gullies comes to about the same conclusion. Researchers examined images of 356 sites, with each of these sites captured multiple times on camera. Of the 38 of these sites that showed changes since 2006, the researchers concluded site changes happened in the winter — when it’s too cold for any liquid water to flow.

This image covers a location that has been imaged several times to look for changes in gullies.  This is in the Terra Sirenum region, part of the southern highlands in the mid-latitudes.  Credit: NASA/JPL/University of Arizona.
This image covers a location that has been imaged several times to look for changes in gullies. This is in the Terra Sirenum region, part of the southern highlands in the mid-latitudes. Credit: NASA/JPL/University of Arizona.

“As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water,” stated lead author Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona.

“We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity occurs in winter.”

Observations were made using NASA’s long-running Mars Reconnaissance Orbiter mission, which has been in orbit there since 2006. The researchers said that these lengthy missions are important for examining and confirming findings, because they can revisit data over time and change their conclusions, as needed, as more evidence comes in. Pictures were taken by the High Resolution Imaging Science Experiment (HiRISE) camera.

A 164-yard (150-meter) wide swath of Martian surface at 37.7 degrees south latitude, 192.9 degrees east longitude shows gullies changing between passes of the Mars Reconnaissance Orbiter. The earlier image, at left, was taken May 30, 2007. Near the arrows on the image on right, which was taken May 31, 2013, is a "rubbly flow" near the channel's mouth. Credit: NASA/JPL-Caltech/Univ. of Arizona
A 164-yard (150-meter) wide swath of Martian surface. It shows gullies changing between passes of the Mars Reconnaissance Orbiter. The earlier image, at left, was taken May 30, 2007. Near the arrows on the image on right, which was taken May 31, 2013, is a “rubbly flow” near the channel’s mouth. Credit: NASA/JPL-Caltech/Univ. of Arizona

The first images of gullies in 2000 sparked speculation that liquid water could be responsible for changing the surface today. It’s true that Mars has water frozen in its poles, and observations with several NASA rovers show strong evidence that water once flowed on the surface. But, these trenches are unlikely to show evidence that liquid water is flowing right now.

“Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but is plentiful on Mars. It has been linked to active processes on Mars such as carbon dioxide gas geysers and lines on sand dunes plowed by blocks of dry ice,” NASA stated.

“One mechanism by which carbon-dioxide frost might drive gully flows is by gas that is sublimating from the frost providing lubrication for dry material to flow. Another may be slides due to the accumulating weight of seasonal frost buildup on steep slopes.”

The team added that smaller features could be the result of liquid water, such as this recent study using MRO. It’ll be interesting to see what other data is churned up as the fleet of orbiters continues making observations, and other scientists weigh in on the results.

The work will be published in the journal Icarus.

Source: Jet Propulsion Laboratory