Home |Space | News  Meteor guide: science and safety of Earth-
bound rocks  The meteor that fell on Russia today took the world
by surpriseMovie Camera – not least because it hit the very same
day that an asteroid is due to fly by Earth. These rocks have
the potential to be highly destructive, but they can also reveal
mysteries about our solar system. Our guide takes you through
the science, and the safety, of Earth-bound space rocks.  What
is the difference between a meteor, a meteorite, a meteoroid and
an asteroid? It's all about location and size. Roughly speaking,
an asteroid is a relatively small body, usually rocky or
metallic that isn't a comet – these are composed of dirt and
ice. Small asteroids are also called meteoroids. When an
asteroid or meteoroid enters the atmosphere and streaks through
the sky, as seen in Russia this morning, it then becomes known
as a meteor. Anything that survives impact is a meteorite.
Whatever you call them, where do these things come from? Most
are from the asteroid belt