comets

Comets “dirty snowballs” in space Contain Dust Gases CO 2 CH 4 NH 3 Leftovers from the beginning of the solar system 4.6 billion years ago

Parts of a comet Head Nucleus – fragments of rock (silicates and metals ) and frozen gases Coma – envelope of vaporized H 2 gas Tail – vaporized gas and dust Sunlight reflects from the vapor Ionized gases tail Dust tail Solar wind pushes the vapor in a direction away from the sun comet tails generally point away from the Sun.

tail As the tail approaches the sun Tail grows longer Tail points away from the sun Comet’s orbit – extremely elliptical continues in orbit to outside of the solar system called the oort cloud where it picks up more dust, rocks and gases.

Oort cloud Belt of material outside of the solar system where comets pick up gas and dust to rebuild its nucleus and coma.

The Kuiper Belt and the Oort Cloud surround our sun, a star. The Kuiper Belt is a doughnut- shaped ring, extending just beyond the orbit of Neptune from about 30 to 55 AU. The Oort Cloud is a spherical shell, occupying space at a distance between five and 100 thousand AU.

Long-period comets (which take more than 200 years to orbit the sun) come from the Oort Cloud. Short-period comets (which take less than 200 years to orbit the Sun) originate in the Kuiper Belt.

Sometime over the next week or so, you may want to pick a clear evening to head outside and look at the sky. If you do, you'll have a chance to see something pretty cool: a comet, streaking past Earth as it orbits the sun. The comet, called C/2014 Q2 (Lovejoy), appears as a beautiful, fuzzy green ball through binoculars, and in some areas, it's even visible to the naked eye.C/2014 Q2 (Lovejoy)