There are certain myths surrounding meteorites and many persist despite reasonable scientific evidence otherwise. Myths persist because the true nature and associated phenomena of meteorites are not understood by the general public. Unfortunately, the main source of knowledge concerning meteorites seems to be from inaccurate movies and a lack of scientific knowledge in general.
Most meteorites are made of iron, right?
Well, yes and no. You see, most meteorites observed to fall are of the stone type. Observed falls of iron meteorites occur only about 4% of the time. However most meteorites that are found are irons because terrestrial weathering breaks down stones more rapidly than irons. In other words, stone meteorites do not survive as long on the Earth’s surface as iron meteorites do (although weathering also eventually affects irons as well).
When they land on the Earth, meteorites always glow with heat from their passage through the Earth’s atmosphere.
Actually, no. Although there is some controversy as to whether or not some meteorites are warm to the touch when they fall, most meteorites are cool when they land on the Earth’s surface. They travel so fast through the Earth’s atmosphere, the heat produced during entry is ablated away, much the same way that the tiles on the underside of the space shuttle (and heat shields on prior space capsules) protect the shuttle. In fact, the aerodynamic shape of oriented meteorites was the inspiration for the blunt heat shield design of the Mercury/Gemini/Apollo space capsules.
Meteorites have been in space for a long time, therefore they are are radioactive, right?
No, meteorites are not radioactive.