What's the connection between a volcanic peninsula in the Pacific Ocean and the icy surface of Europa, a moon of Jupiter? Or the dry, lifeless, inactive surface of Mars? Recent research suggest their origins might share more similarities than you might expect.
Extra-terrestrial volcanoes
Volcanoes do exist outside Earth - in an earlier post I talked about the almost constant volcanic activity on Io, another of Jupiter's moons. Although this is the only known place other than earth where volcanoes are currently erupting, there is clear evidence of past volcanism on Mars, including the massive Olimpos Mons around 25 kilometers high. Our moon also has ancient lava flows, and it is believed that Venus has some volcanic activity, although its dense, hostile atmosphere makes direct observations impossible.
So Earth's surface is constantly being changed and renewed due to plate tectonics. Until recently it was believed that this process is unique to earth, because the volcanoes on Io are caused by a different processes involving gravitational forces, and the sheer size of the Olimpos Mons Volcano suggests a lack of movement, allowing it to keep building up in the same place over a very long period. However several recent research results have presented new evidence of extra-terrestrial plate tectonics.
Detailed studies of a massive, dead straight canyon on Mars, known as Valles Marineris, suggest that it is a feature similar to the San Andreas fault in California - the two sides appear to have moved parallel to each other, displacing older landslides by 159 kilometres. This movement would most probably be driven by convection in the planet's interior, as for the Earth – but being smaller than Earth, Mars would have less internal heat to power any plate tectonic movement, hence the lack of any more obvious plate boundaries.
Another rather intriguing piece of research comes from analysis of images of the surface of Europa taken by the Gallileo spacecraft. Europa's surface is made up of solid ice covered in a complicated network of cracks. In a lot of places the ice is relatively fresh and new, formed as chunks of surface ice move apart, allowing liquid from the interior to come to the surface and freeze as new terrain. In other areas it has now been shown that blocks of old ice are disappearing one underneath another, with ice volcanoes along the boundary – it looks a lot like the plate system on Earth, except in ice rather than rock!
The fascinating implication of this discovery is that it provides a way to move matter, including organic molecules from comets, possible building blocks for life, from Europa's solid surface down to the liquid ocean in its interior.- an ocean that scientist believe could potentially support life. No wonder that Europa is set to be the target of a major NASA spacecraft mission within the next decade!
http://www.mnh.si.edu/earth/text/4_0_0.html Plate tectonics and volcanoes
http://www.jpl.nasa.gov/news/news.php?feature=4285 Evidence of plate tectonics on Europa
http://newsroom.ucla.edu/releases/ucla-scientist-discovers-plate-237303 Evidence of plate movement on Mars
1. Norman Kuring, NASA Ocean Color Group.
2. NASA
3. NASA photo from the Galileo mission