Mercury Presents Weird Dark Halos

Data collected during the fly-by around Mercury by NASA's MESSENGER orbiter is still pouring in, revealing new and surprising facts about probably the least studied planet in the solar system. Upon reviewing some of the photographs taken on January 14, NASA astrophysicists discovered a s... [ read more >> ]

Image of the Caloris Basin, showing the two craters surrounded by dark rims

Image comment: Image of the Caloris Basin, showing the two craters surrounded by dark rims
Image credits: NASA/MESSNGER

Image of the Caloris Basin, showing the two craters surrounded by dark rims