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Transcript of Comets
Swift-Tuttle was discovered in 1862. It is a short period comet (120 year revolution). Tuttle has two special (not for the better) qualities, one it gets closer to the sun every revolution. Also scientists predict that Swift may eventually collide with Earth, but as of now it remains 15,000,000 miles away at its closest point.
By: Tyler Green and Drew Cromwell
What are Comets
Comets are cosmic snowballs of dust, ice, carbon dioxide, ammonia, methane and more. They have a nucleus and two tails.
Where they are from
There are two kinds of comets,
Long-period comets (comets with long, unpredictable orbits) originate in the far-off reaches of the Oort Cloud, which is five thousand to 100 thousand AUs from the sun.
Short-period comets (comets that orbit the sun in less than 200 years) reside in the icy region known as the Kuiper Belt beyond the orbit of Neptune from about 30 to 55 AU.
Comets orbit the sun in ellipses (like planets). Revolutions of Comets we know of range from about 60 years to ten thousands of years. Since the Oort cloud extends so far out (halfway to the nearest star) there could be comets with revolutions of up to hundred thousands of years.
There are two different tails on a comet the ion tail and the dust tail. The ion tail is the tail on the comet that has been ionized or stripped of ions by the sun. The ion tail always faces away from the sun. The dust tail is the tail on the comet that is composed of dust and ice. Both tails grow when they travel towards the sun and shrink when they travel away from it .
Do they serve a purpose???
You may wonder if comets are of importance to us. The answer to that is, YES!
Comets may not be able to support life themselves, but they may have brought water and organic compounds to earth because of collisions with Earth and other bodies in our solar system. Some researchers think comets might have originally brought some of the water and organic molecules to Earth that now make up life here. So in short without comets we may not have ever existed!
We have explained what comets are and their purpose. We have given no examples so here are a few comets...
Hale Bopp is a special and popular comet because of its size and brightness. It was discovered in 1995 by Alan Hale , He was surprised it was so bright, but after careful study they decided it was from its massive size. In fact, Hale Bopp is 20 times as big as an average comet (avg. 2 km Hale Bopp 40 km). Hale Bopp holds the record for the longest period of naked-eye visibility at 19 months. Too bad we will never see it again because it won't be around for another 2,400 years.
Hyakutake was discovered in 1996. it is a long (long, long) period comet with about a 14,000 year revolution. It is average sized and bright. It has shown off one of the longest tails scientists have ever observed on a comet.
solarsystem.nasa.gov › Planets
Our science book
Thanks for Watching!!!
Comet Ison is the most recent comet that was visible on November 28 and 29, 2013. Nasa thought that comet Ison had dissipated as it passed the sun, but after further study Nasa discovered that comet Ison may still have its nucleus intact.