Category Archives: Mars Express

Mars, mars climate, Mars Express

Mars and the Search for Water

Leave a comment

Mars Express Radars Mars

New results from the MARSIS radar on Mars Express give strong evidence for a former ocean of Mars (marked in blue on this artist's concept of what early Mars may have looked like when this ocean existed). The radar detected sediments reminiscent of an ocean floor inside previously identified, ancient shorelines on the red planet. The ocean would have covered the northern plains billions of years ago. Credits: ESA, C. Carreau

It’s one of those no-brainer ideas: that water once existed on the surface of Mars.  All you have to do is LOOK at the planet and you see evidence of something that flowed across the surface.  There are washed out valleys, what look like river canyons, and regions that look like the shores of ancient oceans. If we had geologists (areologists?) on the planet, they’d make short work of determining what it was that flowed across the planet’s surface by taking surface samples and analyzing them.

Well, we don’t have people on Mars — yet. But, we do have spacecraft orbiting the planet and sitting on its surface sending us back all manner of daily data about this rusty, red desert world. The European Space Agency’s Mars Express mission has a radar instrument called MARSIS that bounced signals from the surface back to its detectors. The data in those signals told planetary scientists that at least one part of Mars is covered with sediments that were probably laid down on the floor of an ancient ocean.  The sediments contain minerals and possibly some ices that identify the area as the site of an ocean that existed perhaps 3 or 4 billion years ago, when Mars was very young, and possibly warmer and wetter than what we see today.

The oceans probably didn’t last very long; their water frozen into place, or vaporized and escaped through the planet’s thin atmosphere to space. So, the chances for life to form in those oceans were likely pretty thin.  Life or no life, the evidence for water flowing on the Martian surface in the dim recesses of history is pretty exciting. Now, the questions remain: where did all the water go and was there ever a chance that Mars harbored life?  Stay tuned!

Speaking of staying tuned, have you checked in on this month’s “Our Night Sky” at Astrocast.TV?  If not, why not?  Learn what’s up in the February skies!  You might find Mars…

Mars, Mars Express, Mars Reconnaissance Orbiter, planetary science

Wet Mars

Leave a comment

The Proof is in the Craters

Lyot Crater on Mars, with lines indicating data swaths taken by the Mars Express OMEGA sensor, and NASA Mars Reconnaissance Orbiter CRISM instrument data.. The stars show where hydrated mineerals have been detected. Credits: NASA/ESA/JPL-Caltech/JHU-APL/IAS.

A neat piece of news caught my eye this week — an announcement from the European Space Agency that mineral studies of Mars taken by ESA’s Mars Express mission and NASA’s Mars Reconnaissance Mission show that liquid water was once very widespread on Mars.  The evidence lies inside craters spread around the planet, apparently just beneath the surface. It’s in the form of deposits of what are called hydrated silicates — minerals that have been in contact with water sometime in the past.

Lyot Crater (at left) was one of 91 impact craters the missions studied in a search for evidence of water. At least nine of the craters have strong evidence of hydrated silicates. Those minerals form in wet environments either on the surface or underground — and they have now been identified in both the north and south parts of Mars.

Why study craters?  Because the impacting objects (asteroid chunks, for example) punched down through the surface of the planet and exposed very ancient surface crust that would have been in contact with water. This means that water was widespread on the Martian surface sometime in the past. This is great news for scientists who are working to understand the role that water played on Mars early in its history. The presence of water means that conditions could have been favorable for life. It doesn’t prove that life existed on Mars — that takes other studies and will very likely require us to visit the planet to prove it for sure. But, the existence of water is a big thing.  There are hints of it all over Mars, not just in the hydrated silicates, but in the landforms that seem to be carved by the action of water.  This is a fascinating story that is still unfolding for planetary scientists. I, for one, think that we’ll find substantial reservoirs of water (probably locked away in subsurface aquifers and permafrost) on Mars when our first explorers set foot on that dry and dusty desert surface.