Exoplanet
EK-soh-plan-it
/ˈɛksoʊˌplænɪt/
A planet that orbits a star other than our Sun.
Exoplanets vary widely in size, composition, and orbital characteristics. The search for exoplanets, especially those in the 'habitable zone,' is a major focus of modern astronomy.
The story behind the word. The word 'exoplanet' is a modern compound, combining the Greek prefix exo-, meaning 'outside' or 'external,' with 'planet.' The term 'planet' itself comes from the Greek planetes, meaning 'wandering star,' referring to how planets appeared to wander across the night sky compared to fixed stars. So, an 'exoplanet' is literally a 'planet outside' our own solar system, orbiting another star.
Word relationships
- Extrasolar planet: A more formal and older term for an exoplanet; 'exoplanet' is now more common.
Commonly confused with
- Planet: A 'planet' is a general term for a celestial body orbiting a star. An 'exoplanet' is a planet outside our solar system.
Collocations
- habitable exoplanet
- gas giant exoplanet
- rocky exoplanet
- exoplanet detection
Example sentences
- "The Kepler Space Telescope has discovered thousands of exoplanets, revolutionizing our understanding of planetary systems." Describing a scientific discovery.
- "Scientists are particularly interested in exoplanets located in the habitable zone, where liquid water could exist." Discussing the search for life.
Memory hook
Think 'EXO' (like 'exit' or 'external') + 'PLANET'. It's a planet outside our system. Outside Planet
When not to use
Do not use 'exoplanet' to refer to planets within our own solar system. It specifically means 'outside' our solar system. It's not a synonym for 'alien world' unless you are specifically referring to a planet.
Fun facts
- The first confirmed exoplanet was discovered in 1992, orbiting a pulsar.
- As of 2023, over 5,000 exoplanets have been confirmed, with many more candidates awaiting confirmation.
Explore more words
Also appears in
Take your vocabulary further with LangBlitz
Our English vocabulary app: FSRS spaced repetition, 5,000+ curated words across 119 topic groups, CEFR A1 to C2. Explore your mastery with the beautiful Vocabulary World feature.