Meteor Showers

A girlfriend of mine informed me that this morning was to be one of the best viewings of 2009’s first meteor showers. The optimum time was at 6am and I had good intentions—sleep prevailed. But it got me wondering what exactly was a meteor shower and how do we know when they will occur.

There are three “stages” of a meteor.

Meteoroid: a small body of matter moving in the solar system.

Meteor: a small body of matter from outer space that enters Earth’s atmosphere becoming incandescent (emitting light as a result of being heated from the friction.) Also referred to as a shooting or falling star, meteors travel at thousands of miles an hour.

Meteorite: a meteor that survives the journey without burning up in the atmosphere and strikes the ground. More than 90% of meteorites are rock, the remainder consists wholly or partly of iron and nickel.

A meteor shower is an increase in the number of meteors at a particular time of year. We know when meteor showers will occur because comets orbit and we know their path schedules. As comets orbit the Sun, they shed an icy, dusty debris stream. We have a meteor shower if Earth travels through this stream. Why comets and not asteroids? Asteroids can’t fragment like a comet to produce a shower. If an asteroid enters our atmosphere, it’s still called a meteor.

Comets and asteroids are essentially small planets and vary in size. Comets can be the size of a baseball or several miles across. Asteroids can be several hundred miles across. Comets are rock and ice, asteroids are only rock. Both are bodies left over from the formation of our solar system. Their long existences are apparent from the craters left on the surface of the moon. The moon does not have an atmosphere to protect it so it is much more vulnerable than Earth.

Meteor showers are named for the constellation, or radiant, from which they appear to fall. This morning’s meteor shower was named Quadrantids for the constellation Quadrans Muralis. Saturday and Sunday nights from 6pm–2am will be the last opportunities to potentially see the Quadrantids.

2009 Meteor Showers – Best Viewing Dates
Quadrantids – January 3 (morning)
Lyrids – April 21/22 (night)
Eta Aquarids – May 5
Perseids – August 12 (morning/evening)
Orionids – October 21 (morning)
Leonides – November 17/18 (morning)
Geminids – December 13/14 (night)

For more information, go to http://www.earthsky.org/article/earthskys-meteor-shower-guide

Now you’re a little smarter, Girlfriend — And so am I.