Meteoroids are the particles of space debris orbiting the Sun. They are the source of some of the best backyard stargazing targets.
Smaller than asteroids, they range in size from 10 micrometers up to 1 meter wide.
Mostly made of stone, iron or a combination of the two, these bodies come from comets or asteroids and sometimes from impacts in the Solar System.
These objects in space are no interest to us as backyard stargazers...but they are constantly entering Earth's atmosphere and then they can become very exciting.
When cosmic debris falls into our atmosphere it begins to heat up and emit light. This is a meteor.
Hundreds of times a day this occurs, unfortunately a lot of it happens during the day and/or at remote locations. Most of us though have seen a “shooting” or “falling” star.
That streak of light is the flaming trail of a meteoroid.
I get an extra thrill when I'm out stargazing and get lucky and catch a stray meteor. Even better is a meteor shower.
Meteor showers occur several times a year. These are the results of comets that passed Earth on their trip through the Solar System. As comets approach the Sun they start to heat up and shed particles.
These bits of material left behind in the comet's wake continue in orbit around the Sun.
When Earth impacts these streams we get meteor showers.
Meteor showers are named for the constellation they seem to come from.
For instance the Perseids seem to come from a spot in Perseus. This spot is known as the radiant.
Showers vary but 20 or more meteors per hour is common in the more active showers.
Some showers become storms on occasion and can produce hundreds of meteors per hour.
Meteorites are meteoroids that have survived the meteor stage and managed to reach the ground. Most of the cosmic debris will be destroyed in the upper-atmosphere but some is large enough to have part touch down.
Some in the past have been sufficiently big enough to leave giant impact sites such as Meteor Crater in Arizona.
Impacts on celestial bodies with light or no atmospheres leave craters as a main surface feature. Think of the surface of the Moon for instance. On other bodies with active geologies, like Earth, these features tend to be changed and eroded.Celestial Solar System › Celestial Bodies › Meteoroid