What is a Comet? Comet: A chunk of frozen gases, ice, and rocky debris that orbits the Sun “dirty snowball”

A comet has three main parts:

Comet Orbits vs. Planet orbits long, highly elliptical sometimes close to the sun; sometimes very far from the sun Planet orbits: more circular distance from sun fairly constant

Comet Tails: point AWAY from the sun The coma forms when the sun’s energy causes the frozen gases to “sublimate.” The solar “winds” push the coma away to form the tail.

Two Main Categories of Comet: Short-period Comets Long-period Comets Orbital periods of < 200 years from the Kuiper Belt beyond Neptune’s orbit are the ones usually seen from Earth Orbital periods > 200 years from the Oort Cloud on the outskirts of the solar system

Comets: leftover debris from the formation of the solar system 4 Comets: leftover debris from the formation of the solar system 4.6 billion years ago! Scientists want to study comets to learn more about the formation of the solar system.

A famous comet: Comet Halley Edmund Halley predicted its return orbital period: 76 years Last seen from Earth 1985-1986 When will it return….?

Comet Halley Actual photograph of the nucleus of Halley’s Comet

Comet C/ 2011 L4 PanSTARRS – named for the telescope through which it was discovered in June 2011: Panoramic Survey Telescope and Rapid Response System (or PAN-STARRS), a telescope atop the Haleakala volcano in Hawaii.

Will we see it….?

When will PanSTARRS return. Maybe never When will PanSTARRS return? Maybe never! It looks like this comet’s orbit might be parabolic… If it does return, it might not be for another 100,000 years…

Where did it come from? Most likely from the Oort Cloud:

Should be visible in late November – maybe even in the daytime! Comet C/2012 S1 (ISON) Should be visible in late November – maybe even in the daytime!

Speculation: Is this the same comet as the Great Comet of 1680?????

http://amazing-space. stsci http://amazing-space.stsci.edu/resources/explorations/comets/lesson/lab.html 1. Make your own virtual comet. 2. Read some comment myths and legends. 3. Test your knowledge with “Comet Tails.”