Mars Weathercam Spots Big New Crater npr

Before and after shots taken by a Mars-orbiting satellite have detected a newly created impact crater half the size of a football field near the planet’s equator.
NPR’s Joe Palca says that while objects are striking Mars all the time (with big chunks surviving until impact, thanks to the Red Planet’s thin atmosphere), this is the first time scientists have been able to determine the exact day a meteor struck – in this case, sometime on March 28, 2012.
But it wasn’t noticed until two months ago.