astronomy

noun as·tron·o·my \ ə-ˈsträ-nə-mē \

|Updated on: 6 Aug 2018

Editor's Note: The Difference Between astronomy and astrology

Definition of astronomy

plural astronomies

: the study of objects and matter outside the earth's atmosphere and of their physical and chemical properties

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Recent Examples of astronomy from the Web

Ever since the 1950s, when physicists first dreamed up the idea of doing astronomy with neutrinos, the holy grail has been to observe the first object outside our solar system that emits these ghostly particles.

— mark bowen, Scientific American, "Neutrinos on Ice: Astronomers' Long Hunt for Source of Extragalactic "Ghost Particles" Pays Off," 12 July 2018
Scientists, for instance, could use smallsats to do time-domain astronomy: watching for bursts and flares and flashes and pulses and all the other kinds of light-waves that appear and then vanish.

— sarah scoles, WIRED, "NASA’s New Plan: Do More Science With Small Satellites," 21 June 2018
While growing up in East Granby, Daniel loved nature and astronomy and also competed as a youth body builder and was named Mr. Teenage Connecticut in the early 1970's.

— courant.com, "Daniel Wesley Rose," 8 July 2018
Instead of sun proximity, the seasons depend on the earth's spin axis, said Miami University associate professor of astronomy and physics Stephen Alexander.

— madeline mitchell, Cincinnati.com, "Summer solstice: What is it and why does it happen?," 20 June 2018
His course will include the Toltecs, Aztecs and Mayans, with their accomplishments in physics, astronomy and architecture.

— krista torralva and alia malik, San Antonio Express-News, "Some area schools already plunging into Mexican-American studies," 10 June 2018
Summit will be used, in part, to invigorate research on artificial intelligence, astronomy and health care.

— josh axelrod, CNN, "This computer can do more calculations per second than the world's population could do in a year," 9 June 2018
Gheens Science Hall and Rauch Planetarium at the University of Louisville enables visitors to explore the wonders of astronomy and space science.

— The Courier-Journal, "A break from the classroom doesn’t have to be a break from learning," 26 May 2018
Being an Aztec means studying anything from information systems and sustainability to astronomy and hospitality.

— karla peterson, sandiegouniontribune.com, "Why the battle over SDSU's Aztec Warrior is a win for all Aztecs," 23 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'astronomy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

The Difference Between astronomy and astrology

Some may find it easy to confuse astronomy and astrology. At one time, these two words actually were synonymous (that is, astronomy once meant what astrology means today), but they have since moved apart from each other. In current use, astronomy is concerned with “the study of objects and matter outside the earth's atmosphere,” while astrology is the purported divination of how stars and planets influence our lives. Put bluntly, astronomy is a science, and astrology is not.