Last image sent by the Messenger space probe.
A new crater is detected on Mercury! Er - rather, a new crater was created on Mercury, as the Messenger space probe crashed into the far side of the little planet. After 4 years and 250,000 images, the NASA Messenger spacecraft program came to a close, and the satellite was allowed to smack into the surface at about 8,700 miles per hour. The are no images of the crash itself, as it occurred on the side of Mercury facing away from Earth telescopes, and space telescopes were unable to face the crashpoint as the planet was too close to the glare of the Sun.
NASA infographic of the success of Messenger.
Messenger completed its mission in 2012, but it was in good enough shape to continue experiments and reconnaissance. It successfully discovered Mercury's off-set internal magnetic field, imaged water ice deposits at the poles, and helped scientists unravel the geological history of the planet.