Are meteorites hot when they land?
Usually not. The outer skin melts for only a few seconds high in the atmosphere, and the cold interior means most fresh meteorites are cool, warm at most, when they reach the ground.
It is one of the most persistent myths: films show glowing, smoking rocks sizzling in craters. In reality, most freshly fallen meteorites are cool to the touch, or at most slightly warm.
The reason lies in timing. The fiery part of a meteorite's journey, when its surface is heated to melting point, lasts only a few seconds and happens many kilometres up. The melt is blown away almost as soon as it forms, carrying the heat with it, so only a skin less than about a millimetre thick ever gets truly hot. That skin hardens into the dark fusion crust. The inside of the rock, meanwhile, has been soaking in the cold of space for millions of years and stays cold, because stone conducts heat poorly.
After the glow stops, the meteorite then falls for several minutes through cold air during dark flight. By the time it lands, the thin hot skin has had plenty of time to cool down. Some witnesses have even described freshly fallen stones as cold, and there are old accounts, such as the fall at Colby in Wisconsin in 1917, of frost forming on a newly landed meteorite.
There are exceptions. Some recovered stones have been described as warm, and a large mass that hits hard can create heat on impact. Meteorites do not start fires in ordinary falls, though. If you ever see one land, do not grab it with bare hands anyway: not because of heat, but because skin oils and moisture can contaminate a scientifically precious fresh sample. Lift it with clean aluminium foil or a clean plastic bag, note the exact spot, and contact a museum or university.