Comets

Snowballs in the Outback

Comets come from the outback of the Solar System. Icy remnants left behind from the formation of the Sun and planets, they are the most beautiful of all. Bright comets have been noted throughout history, instilling a variety of emotions including fear, awe and gladness.

It was once believed that comets were harbingers of disaster which moved within Earth's atmosphere. Wars, plagues, famine and death have been blamed on comets. It is hard to imagine how such a beautiful object gracing our skies could be associated with such evil.

The great astronomer Tycho Brahe discovered that comets were beyond Earth's orbit in 1577. He spent years making observations and finally concluded that since the comets did not show a parallax (an apparent displacement of an object against the background stars when viewed from different locations) when viewed from different locations on Earth. Tycho estimated that the comets were at least three times farther away than the Moon.

Though dozens of new comets are discovered each year, it is rare for naked eye comets to appear. We have been treated to two such comets this decade, Hyakutake in 1996 and Hale-Bopp in 1997. Hale-Bopp may well be considered the comet of the century.

• The Best Way to Watch a Meteor Shower
• Where to Look for the Leonids
• Star Charts
• Leo
• Photographing Meteor Showers
• Other Meteor Showers
• What are Meteors and Meteorites
• Origin of Meteorites
• Thunderstones and Shooting Stars: Meteors and Meteorites in Folklore
• Asteroids and Comets: Proud Parents of Meteors
• Target Earth
• Links to other good sites about the Leonids
• More images

Constellations

The Solar System