Thursday, April 17, 2014

Mars isn't static!

One of the old stories has always been that things in space are never changing. The stars were fixed to the celestial sphere and stayed in place like a light fixture with a few thousand bulbs. What made the planets different from the stars was their movement. We now know that stars aren't static either: their light changes, some blow up, some have planets moving around them, some orbit one another, and some whip around our galaxy's center at incredible rates due to the giant black hole there.

Even though we know that the Solar System isn't unchanging, it still is surprising to see a change. Jupiter got walloped by a comet in 1994 and telescopes caught each explosion. The moons Enceladus around Saturn and Io around Jupiter erupt occasionally and the plumes can be seen in space. And now, researchers at NASA have caught a subtle change on Mars. Something common on Earth was captured on mostly dry Mars: a gully changed course.

"A comparison of images taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter in November 2010 and May 2013 reveal the formation of a new gully channel on a crater-wall slope in the southern highlands of Mars" http://www.jpl.nasa.gov/news/news.php?release=2014-086

Scientists do not know what time of year that the gully changed.In the area on Mars where this gully lies (Southern Highlands), however, gullies often change in the winter when it is far too cold for liquid water to exist. Martian winters get so cold that carbon dioxide may condense out of the atmosphere and be involved with gully formation. Or perhaps liquid (probably salty, because it didn't freeze in the very cold martian air) water was involved. Either way, this new gully is a good reminder to us that Mars, like Earth, is not static. It's a world where things happen.




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