exoplanet

EK-soh-PLAN-it /ˌɛksoʊˈplænɪt/
nounC1GRE
scientific

A planet that orbits a star other than the Sun.

Distinguishes planets within our solar system from those outside it. The study of exoplanets is a relatively new and rapidly expanding field of astronomy.

The story behind the word. The word 'exoplanet' is a modern coinage, combining the Greek prefix `exo-`, meaning 'outside' or 'external,' with the word 'planet.' It literally means 'outside planet,' perfectly describing a planet that exists beyond our own solar system. This term emerged as astronomers began to confirm the existence of such worlds in the 1990s.

Word relationships

  • extrasolar planet: A more formal and older term, but 'exoplanet' is now more common.

Commonly confused with

  • planet: An exoplanet is a type of planet, specifically one that orbits a star other than our Sun. 'Planet' is the general term.

Collocations

  • habitable exoplanet
  • super-Earth exoplanet
  • gas giant exoplanet
  • transiting exoplanet
  • distant exoplanet

Example sentences

  • "Scientists have discovered thousands of exoplanets, some of which may have conditions suitable for life." Describing astronomical discovery.
  • "Future telescopes are being designed specifically to detect and characterize the atmospheres of distant exoplanets." Discussing future space missions.

Memory hook

An EXOskeleton is outside the body; an EXOPLANET is a planet outside our solar system. EXO-PLANET = outside planet.

When not to use

Do not use 'exoplanet' for planets within our solar system (e.g., Mars, Jupiter).

Fun facts

  • The first confirmed exoplanet was 51 Pegasi b, discovered in 1995.
  • The Kepler Space Telescope discovered thousands of exoplanets using the transit method.

Related words

planet, star, galaxy

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