Today is a big day for lovers of the planet Mercury, the closest planet to the sun.
NASA's MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) vehicle will start to orbit Mercury today.
Of all the terrestrial planets, Mercury remains one of the most mysterious.
NASA's Mariner 10 took some photos during flybys back in 1974 and 1975. And more recently, MESSENGER took some photos and grabbed some samples on a flyby in 2008.
The New York Times had a piece on what scientists learned about Mercury from the 2008 flyby:
An instrument aboard Messenger sampled Mercury’s surface composition by catching some of the charged atoms that have been knocked into space. Silicon, sodium and sulfur were detected. So was water.
“Which is a real surprise,” said Thomas H. Zurbuchen, an associate professor of atmospheric, oceanic and space sciences at the University of Michigan and lead author of another paper in Science. “The first time we took a whiff of the planet, it’s right there.”
One possibility is that the water exists as ice in the shaded parts of craters in the polar regions.
Today, MESSENGER will begin orbiting the planet every 12 hours. Engineers at the University of Michigan say "an onboard device dubbed FIPS (Fast Imaging Plasma Spectrometer), a soda-can sized sensor designed and built at the University of Michigan will take atmospheric measurements, studying the evolution of rocky planets as it orbits Mercury."
Here, Thomas Zurbuchen, the lead engineer from the University of Michigan, talks about FIPS: