Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Halley's Comet
Name: AM Jones
Status: Other
Age: N/A
Location: N/A
Country: N/A
Date: Prior to 1993


Question:
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.



Replies:
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.

John Hawley


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 ellipses.

Sam Bowen


Click here to return to the Astronomy Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory