Halley's comet[hălˈēz, hāˈlēz]
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a famous comet, last seen in 1986, whose reappearance about every 76 years was predicted by Edmond Halley
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The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A comet with a period of approximately 76 years. The first comet for which a return was successfully predicted, it last appeared in 1986.
Origin: After Edmund Halley.
halley's comet - Science Definition
The American Heritage® Science Dictionary
A short-period comet that orbits the Sun once every 76 years. It is visible to the unaided eye and last appeared in 1986, when close observation by spacecraft showed that its nucleus measures about 16 km (10 mi) by 8 km (5 mi) and is composed of water ice, stony minerals, and organic compounds. Its next appearance will be in the year 2061.
Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.