Comets, Asteroids and Meteors

Comets and Asteroids

Comet West

Asteroid Eros

Asteroid Ida

Comet Halley

Comets Asteroids

                               

Comet Hyakutake

                               

Artist's concept of an asteroid

Made up of ice and dust Made up of rocks and metals

Form tails when they pass through the inner solar system

Do not form tails

Typically have orbits that are very much more elliptical and tilted than those of the planets

Typically have orbits that are more elliptical and tilted than those of the planets

Usually orbit the Sun in two regions: the Kuiper belt (about 30 to 100 AU from the Sun) and the Oort Cloud (extending out to about 50,000 AU from the Sun)

Usually orbit the Sun in the asteroid belt, a region between Mars and Jupiter

Meteor showers usually occur when Earth passes through a stream of particles left behind by a comet in its orbit

Produce meteors (streaks of light) upon entering Earth’s atmosphere; produce meteorites if they (either whole or in part) survive the trip through Earth’s atmosphere and hit the ground

Typically remain in the outermost regions of the solar system (beyond the orbit of Neptune), but can pass through the inner solar system if their orbits are elliptical enough

Typically remain in the asteroid belt, a region between Mars and Jupiter

May or may not orbit the Sun in the same direction as the planets

Orbit the Sun in the same direction as the planets

Usually undetectable to the naked eye; may become visible while passing through the inner solar system

Virtually undetectable to the naked eye

Comets Asteroids

Meteor Showers• Meteor shower sometimes occur when the Earth passes

thru the orbit of a comet. Some occur with great regularity: the Perseid meteor shower occurs every year between August 9 and 13 when the Earth passes thru the orbit of Comet Swift-Tuttle. Comet Halley is the source of the Orionid shower in October.

• Meteor showers are named by the constellation from which meteors appear to fall, a spot in the sky astronomers call the radiant. For instance, the radiant for the Leonid meteor shower is located in the constellation Leo. The Perseid meteor shower is so named because meteors appear to fall from a point in the constellation Perseus.

Colorado astrophotographer Gary Emerson captured the fury of the great 1966 Leonid meteor storm, the most spectacular storm of the 20th Century. This image was taken over 20 minutes and records only the brightest meteors. At the storm's peak, Emerson says he saw thousands of meteors per second.

Meteors

• Commonly called “Shooting Stars”– Rock or dust that is burning in Earth’s

atmosphere– We see them as a streak of light across the sky

• Meteorite– Rock that makes it to Earth– Typically burnt exterior and metal