Name: AM Jones
Date: Prior to 1993
Why does Halley's comet make an elliptical orbit around the sun?
Why does the comet not fly into space? Explain the type of gravitational
field that controls this comet.
Halley's Comet appeared 7 or 8 years ago and has a period of 76
years, so it will not reappear for another 69 years. It varies from 74 to 78
years, so the average is about 76 years. The reason for the variation is
unpredictable interactions with the gas giants, mostly Jupiter.
The kind of gravity that attracts the comet to the sun is exactly
the same as we experience here on earth. The way we can know that is because
the orbit is so close to being an ellipse. Newton's discovery was that for
gravity the orbits of objects that cannot escape are either circles or
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Update: June 2012