October 19, 2017

10.10.09: An Active Mercury?

An atmosphere. Magnetosphere. Signs of recent geological activity…is it Mars? Europa? Some far off exo-planet? Nope…its none other than Mercury, a visual twin of our own Moon and long thought of as just as inactive. The past three flybys of NASA’s Messenger spacecraft have revealed a world of dynamic activity. First, there is Mercury’s on-again, off-again magnetic field, a sign that it may possess an active core. Now that 95%+ of the surface has been visualized, a picture is emerging of a crater pocked surface that has also been shaped by recent volcanism. Finally, Messenger has picked up tenuous traces of magnesium out-gassing from the planet as a result of the intense solar radiation bombarding the sun-ward side, contributing to a tenuous trailing exosphere. The 3rd pass last week was the closest yet, and revealed more stunning photos of what is now the tiniest “planet…” Messenger will enter a permanent orbit in 2011. Google Mercury, anyone?