Is there life on Mars? We haven’t answered Bowie’s question yet. Is there ice on Mars? Yes, and possibly more than we thought.
NASA’s Phoenix Lander found water ice at the north pole of Mars back in 2008, so we know ice does indeed exist on the Red Planet, but new findings suggest it could exist beyond the planet’s extremities. The question is whether it could be sustained—and even sustain life. When NASA unearthed hydrated salts in the recurring slope lineae (RSLs) that streak the sides of Martian craters, excitement arose with just as many questions. Where do they come from? Does the sun make them more obvious in warmer weather? Are RSLs even salts at all?
Scientists have conflicting views on the RSLs. Some believe the streaks are nothing but barren sand because they tend to fall in straight lines rather than the waves that are typical of water. Some insist they did emerge from water, but the source, amount, and capacity for sustaining alien microbes is still a mystery. Recently, a team of researchers looking through the lens of NASA’s Mars Odyssey spacecraft investigated them further through images that were sharpened to bring the view from 340 miles away to 170. That’s way beyond HD.
The team found enough hydrogen to convince them there was at least a possibility of water.
"In bringing the lower-resolution compositional data into sharper focus, we saw unexpectedly high amounts of hydrogen—a potential sign of buried water ice or very hydrated salts — around sections of the Martian equator," said team lead and planetary scientist lead Jack Wilson, who recently published the study in the journal Icarus.
This seemed like a breakthrough until they realized it was also the same amount of water in regions with and without RSLs. Meaning they probably aren’t hydrated by water from the subsurface, but there’s a catch. The neutron data gathered by the team has a resolution of around a hundred miles, and RSLs are only a little over 300 feet long, so higher levels of water could have gone undetected. Odyssey could have missed something.
"Where this water came from and why it is still present near the surface are interesting questions," Wilson added.
What no orbiting spacecraft can do is find out exactly how much water lies beneath the surface of Mars. A rover would be needed to carry out anything more invasive than transmitting images, but any craft that lands on the surface risks contaminating samples with microbes that may have hitched an interplanetary ride from Earth.
Mars has no water ice at its lower latitudes and equator because of an atmosphere that is all but nonexistent, but maybe the Mars 2020 rover could prove that wrong.