parsec

[ pahr-sek ]

noun

, Astronomy.

1. a unit of distance equal to that required to cause a heliocentric parallax of one second of an arc, equivalent to 206,265 times the distance from the earth to the sun, or 3.26 light-years.

parsec

/ ˈpɑːˌsɛk /

noun

1. a unit of astronomical distance equal to the distance from earth at which stellar parallax would be 1 second of arc; equivalent to 3.0857 × 10 ¹⁶m or 3.262 light years

parsec

/ pär′sĕk′ /

1. A unit of astronomical length equal to 3.26 light-years. It is based on the distance from Earth at which a star would have a parallax of one second of arc. Its metric equivalent is about 30.8 trillion km (19.1 trillion mi). It is used in measuring distances in interstellar and intergalactic space. The closest star to Earth, Alpha Centauri, is about 1.3 parsecs away.
2. Compare astronomical unit

Word History and Origins

Origin of parsec¹

First recorded in 1910–15; par(allax) + sec(ond) ²

Word History and Origins

Origin of parsec¹

C20: from parallax + second ²

Example Sentences

In the innermost region -- within 0.1 parsecs of the black hole -- few stars escape unscathed.

From Science Daily

One of the closest candidates of this size is the red supergiant Betelgeuse in the constellation of Orion, located at a safe distance of about 150 parsecs from our solar system.

From Science Daily

No matter how many times I watch my favorite sci-fi films and series, I still can’t tell a parsec from a cylinder of drugstore plutonium.

From New York Times

It is the fastest hunk of junk in the galaxy and capable of completing the Kessel Run in less than 12 parsecs.

From BBC

Indeed, in a separate study published in Nature in June 2020 suggested that some fast radio bursts could be coming from a magnetar in our galaxy nearly 10,000 parsecs away.

From Salon