FOR THE RECORD - June 14, 2009

Meteorite bombardment: In Section A on June 7, an article about a meteorite barrage that may have provided ingredients for life on Earth said that the meteorites may have been stripped of “oxygen- and water-rich outer layers” by “frictional heat” as they entered the atmosphere. It should have said carbon dioxide instead of oxygen; and the heat from such events is caused not by friction but by “ram pressure,” in which compression heats air around the meteorite.