Meteors or Shooting Stars are small bodies consisting of iron, stone, and certain other familiar elements which are scattered in immense numbers through planetary space; they revolve round the sun in clouds or in long strings, and when the earth gets close to them numbers are drawn down to its surface, friction with the atmosphere rendering them luminous and grinding them usually to fine dust; larger meteors are known as fireballs and aërolites, many of which have reached the earth; comets are masses of meteors.