MARS–BEATEN AND BATTERED

The following information was taken from EarthSky.org, The University of Colorado and Discover Magazine.

We earthlings have always had a very real fascination with the planet Mars.  My first recollection was from reading a book by Edgar Rice Burrows: “Princess of Mars”.  Great book and one that was recently made into a movie.  As usual, the hero was dashing and the princess was beautiful.  Could it have been any other way?

There, of course were others—many others.  These go back at least sixty years and maybe longer.

Reality is, Mars is a very well-worn planet and one that has a past.    It is a beaten and battered planet. This is according to a research team that recently finished counting and cataloging a staggering 635,000 Martian impact craters.   Astronomers have been peering for centuries at the craters created by cosmic buckshot pounding its surface over billions of years.   From here on Earth we certainly don’t see the evidence of those impacts.  All looks placid, quiet and very smooth.  We definitely must look much closer to get a picture of what 635,000 + craters can do to the surface of any planet.

Just how beat up is it?

Really beat up, according to a University of Colorado Boulder research team that recently finished counting, outlining and cataloging the impact craters existing on the surface of the red planet.  Each crater is roughly a kilometer or more in diameter.  As the largest single database ever compiled of impacts on a planet or moon in our solar system, the new information will be of help in dating the ages of particular regions of Mars, reported CU-Boulder postdoctoral researcher Stuart Robbins, who led the effort. The new crater atlas also should help researchers better understand the history of water volcanism on Mars through time, as well as the planet’s potential for past habitability by primitive life.

A paper on the subject by Robbins and CU-Boulder faculty member Brian Hynek appeared in June 2012 in the Journal of Geophysical Research – Planets, a publication of the American Geophysical Union. A companion study by the two CU researchers was published in a recent issue of the same journal. The study was funded by NASA’s Mars Data Analysis Program.

Hynek, a LASP research associate and assistant professor in the geological sciences department, said knowing more about the history and extent of Martian cratering has implications for better understanding the potential for past life on Mars. He said:

Many of the large impact craters generated hydrothermal systems that could have created unique, locally habitable environments that lasted for thousands or millions of years, assuming there was water in the planet’s crust at the time. But large impacts also have the ability to wipe out life forms, as evident from Earth’s dinosaur-killing Chicxulub impact 65 million years ago.

“Having a better handle on the size and distribution of Martian impact craters also has implications for future, manned missions to the planet, said Hynek. NASA wants to know where the craters are and their particular features both from a safety and research standpoint.   He said:

Craters act as a ‘poor man’s drill’ that provide new information about the subsurface of Mars.

Cataloging craters like the one above for Mars and our own moon is helping scientists understand the time line hundreds of million years after the inner solar system formed, including an event about 3.9 billion years ago known as the “Late Heavy Bombardment” in which asteroids as large as Kansas rained down on Earth. Hynek said:

Although Earth has lost most of its geologic record due to tectonic plate movements and erosion, understanding the impact crater history on the moon and Mars can help us reconstruct our early days.

The photo above shows the Melas Chasma on Mars, which reaches a depth of 5.6 miles; it is part of the staggering Valles Marineris rift valley, which stretches almost 2,500 miles across the surface of the red planet.  For comparison’s sake, our earthly Grand Canyon is 1.1 miles deep and 277 miles long.  This Chasm was undoubtedly created by an impact from a falling asteroid.   This remarkable image was taken by the High Resolution Stereo Camera on the European Space Agency’s Mars Express orbiter. In addition to giving us something neat to gawk at, the image also reveals evidence of Mar’s watery past.

Part of the canyon wall collapsed in multiple landslides in the distant past, with debris fanning out into the valley below.  Scientists analyzing the texture of the rocks deposited by the landslides say they were transported by liquid water, water/ ice, or mud.    Our own Curiosity Rover is giving us tremendous quantities of new information relative to the Marian surface.   Rover is looking for the following:

•  Water or evidence of there having been water
• Minerals that lie on the surface and subsurface
• Any trace of an atmosphere
• LIFE —  large or small

I suspect we will find Mars to be a planet in which life was thriving at one time in the very distant past.  Let’s just hope this is not predictive of what we may find at some future time here on Earth.  At any rate, Mars continues to be a planet of significant mystery.