After 11 years and 4,104 orbits around Mercury, NASA's Messenger orbiter will crash into the planet closest to the sun later today, reports NPR. The orbiter was launched in 2004 and has been collecting data on Mercury since it began circling the planet in 2011. You can follow Messenger's final moments on its' official Twitter page.
Well, I've got 3 hours and 26 minutes left. :-(
ā MESSENGER (@MESSENGER2011) April 30, 2015