Mars is the seventh largest planet in our solar system and has been more robotically explored than any other planet outside Earth since the 1960s.
Imaging with Mariner 9 in 1971 revealed the first direct evidence of water on the Red Planet. But it was only thanks to the recent ESA ExoMars and Mars Express missions that water frost was observed for the first time near Mars’ equator, a part where it was thought frost could not exist.
More information: Natural Geosciences
Dr. Adomas Valantinas and his team recently shared the news about evidence of water frost near Mars’ equator
Image credits: European Space Agency
Image credits: European Space Agency
Image credits: European Space Agency
The water frost was observed over the Tharsis Montes region, on top of the Olympus Mons volcano, which rises some 25 kilometers above the surface of Mars and is three times as high as Mount Everest, the highest not only on Mars but in the entire solar system. The remarkable discovery was first made by ESA’s ExoMars Trace Gas Orbiter (TGO), and then by TGO and ESA’s Mars Express.
The new data suggests that the frost is only noticeable a few hours after sunrise before melting in sunlight. Because Mars has a much thinner atmosphere than Earth, surface temperatures on the Red Planet can reach as high as 70 degrees Fahrenheit and as low as -225 degrees Fahrenheit.
“We thought it was unlikely that ice would form around Mars’ equator because the mix of sunshine and a thin atmosphere keeps temperatures relatively high during the day, both on the surface and on the mountain top – unlike what we see on Earth where you would expect to see icy peaks,” says Dr. Adomas Valantinas, who made the discovery as a PhD student at the University of Bern, Switzerland, and is now a postdoctoral researcher at Brown University, USA.
The research team suspects that the way air circulates above volcanic mountains may create the very specific microclimate that allows those thin ice particles to transform into very thin layers about the width of a human hair. Despite being so thin, the frost covers an incredibly large area: the amount of frost represents about 150,000 tons of water, which is the equivalent of about 60 Olympic swimming pools.
“Its existence here is exciting and indicates that exceptional processes are at play that allow frost to form,” Valantinas added. “What we’re seeing could be a remnant of an ancient climate cycle on modern Mars, where in the past you had precipitation and maybe even snowfall on these volcanoes.”
The frost was spotted with TGO’s CaSSIS instrument over the Tharsis Montes region, atop the Olympus Mons volcano
Image credits: European Space Agency
Image credits: European Space Agency
Image credits: NASA
Image credits: Semhur
Although this new discovery marks the first time that water frost has been observed near Mars’ equator, many of us are probably wondering why it wasn’t noticed sooner.
“There are a few reasons: first, we need an orbit that allows us to observe a location in the early morning. Although ESA’s two Mars orbiters – Mars Express and TGO – have such orbits and can observe at any time of the day, many from other organizations are instead synchronized with the Sun and can only observe in the afternoon,” explains Valantinas out.
“Second, frost deposition is associated with colder seasons on Mars, which further reduces the chance of detecting it. In short, we need to know where and when to look out for short-term frost. For other research, we happened to be looking for it near the equator, but we didn’t expect to see it on the volcanic peaks of Mars!” he added.
The frost was spotted with TGO’s CaSSIS instrument and then confirmed by looking at the area again using TGO’s Nadir and Occultation for Mars Discovery (NOMAD) spectrometer and Mars Express’ High Resolution Stereo Camera (HRSC).
“This discovery was possible thanks to the successful collaboration between both ESA Mars orbiters and additional modeling. Understanding exactly which phenomena are the same or different on Earth and Mars will really challenge and improve our understanding of basic processes taking place not only on our home planet, but elsewhere in the cosmos,” says Colin Wilson, ESA Project Scientist for both ExoMars TGO and Mars Express.
“Finding water on the surface of Mars is always exciting, both for its scientific importance and for its implications for human and robotic exploration,” he added. Wilson also pointed out that this new discovery is really special because it shows that despite the low atmospheric pressure of Mars, which creates an unusual situation (the planet’s mountain peaks are usually no colder than the plains), it seems that moist air can still condense into frost. – an Earth-like phenomenon.
Another study examined lava tubes on the surface of Mars that could provide astronauts with protection from the extreme conditions in the future
Image credits: NASA
Image credits: NASA
Image credits: NASA
Another discovery made by another probe recently re-examined a series of mysterious holes, about 3 meters wide, located on the flanks of volcanoes in the Tharsis region of Mars.
Scientists believe these holes are “skylights,” or places where the ground above the lava tubes has collapsed and created a hole in the surface. If these lava tubes are similar to the ones we have on Earth, then they could provide astronauts with protection from extreme conditions such as solar radiation, micrometeorites, extreme temperature fluctuations, wind, etc. and regolith dust storms, according to Brandon Johnson, a geophysicist at Purdue University.
‘There’s more than one [pits] on Mars that we have seen,” said Johnson, who studies impact craters throughout the solar system. “But they are really interesting because they are places where astronauts can go and are safe from radiation.”
But to better understand the circumstances, a more detailed investigation is absolutely necessary.
“On Earth, these lava tubes can be large enough to walk around in, but they can also be small and the voids can be discrete or discontinuous,” says Ross Beyer, a planetary scientist at the SETI Institute.
“So these pits we’re seeing could lead into larger caverns, or they could just be isolated pits. There’s no way of knowing what’s in them until we examine them in more detail,” he explained.
Johnson said the best way to get more information about the conditions inside lava tubes would be to physically enter them using a rover: “There have been missions proposed to essentially put a robot on a line and into one of these to drop skylights and be able to discover what is inside them.”
Because the mysterious holes could hypothetically provide shelter from the planet’s hard surface, they could also be the best place to look for possible alien life.
Image credits: European Space Agency
Image credits: NASA
Image credits: NASA
The Tharsis region covers almost 25% of the Red Planet’s surface and each new study provides scientists with vital information for future exploration and the search for possible signs of life.
Right now the only information comes from orbiting cameras in space, but hopefully it will soon be possible to physically explore Mars. And who knows how the most Earth-like planet will surprise us next time.
People on the Internet shared their excitement about the new discoveries on Mars