On the Today programme on Radio 4 this morning, there was an item about the acquisition of an important meteorite by the Natural History Museum. One of the presenters said they didn't know the difference between a comet and a meteor, and everyone else in the studio said that they didn't either. If they had said they didn't know the difference between a meteor and a meteorite, that would have been fair enough. Or even if they had been embarrassed about not knowing - but no, they were quite pleased with themselves!
I expect they would laugh at people who didn't know the difference between, say, Cézanne and Monet; but they seem to think it's fine not to understand a fairly basic piece of science. Nor is this a one-off incident; similar things have happened several times on the Today programme (like the time someone felt the need to point out that the Earth orbits the Sun).
It's simple really - a comet is a big ball of dirt and ice which has an elliptical orbit around the sun, which acquires a tail and a coma due to the ice melting as it gets closer to the sun; and a meteor is a shooting star (a small piece of space debris, often a fragment of asteroid) that has a decaying orbit and gets caught in the Earth's gravitational field and burns up on entry to the atmosphere.
Balador checked that the above was correct by going to a helpful NASA FAQ page, which has a neat little table:
|Asteroid||A relatively small, inactive, rocky body orbiting the Sun.|
|Comet||A relatively small, at times active, object whose ices can vaporize in sunlight forming an atmosphere (coma) of dust and gas and, sometimes, a tail of dust and/or gas.|
|Meteoroid||A small particle from a comet or asteroid orbiting the Sun.|
|Meteor||The light phenomena which results when a meteoroid enters the Earth's atmosphere and vaporizes; a shooting star.|
|Meteorite||A meteoroid that survives its passage through the Earth's atmosphere and lands upon the Earth's surface.|