Mystery Rising Within Mercury 120
astroengine writes "Something besides volcanic eruptions and asteroid and comet impacts has sculpted the surface of Mercury — an unknown process, possibly still going on today, that causes the ground to swell from the inside out. The evidence, collected by NASA's MESSENGER spacecraft currently orbiting the innermost planet, is scattered all over Mercury, including a dramatic finding that half of the floor of the biggest crater on the planet has been raised above the walls. The MESSENGER team's findings were announced at the Lunar and Planetary Science Conference in Houston on Wednesday and will be published in this week's Science."
What about this is unusual? (Score:5, Interesting)
I didn't see any mention in the linked article about what makes these features particularly odd. It says parts of the crust are tilted and raised by several kilometers in places. This is pretty commonplace geology caused by plate tectonics here on Earth (we call them mountain ranges). If Mercury has a liquid mantle, would we not expect to see similar folding and up-thrusting there? Is this different because of the size, shape, speed of movement?
Why so much core? (Score:5, Interesting)
Makes me wonder if Mercury was once the core of a much larger planet, and rhe mantle got knocked off in an impact.