"It Came from Outer Space": Mars' Odd 'Block Island' Meteorite -A Clue to an Ancient Atmosphere

"It Came from Outer Space": Mars' Odd 'Block Island' Meteorite -A Clue to an Ancient Atmosphere: "The odd meteorite weighs at least half a ton, making it much too large to have plunged through Mars' current thin atmosphere and hit the surface without an impact that would have obliterated the object upon impact. Either the atmosphere was thicker than expected some time in the relatively recent past, NASA scientists argued, or the rock fell to the surface billions of years ago when the atmosphere was considerably thicker."