FIELD NOTES

Science, explained.

Clear answers to the questions that make other worlds so fascinating.

An exoplanet is a planet beyond our Solar System. Most orbit other stars; some travel through space without a stellar companion.

Astronomers look for repeatable signals in light, motion and gravity, then test whether a planet is the best explanation.

A tiny, regularly repeating dip in starlight can reveal a planet crossing its star.

A star’s subtle motion can betray the gravitational pull of an unseen planet.

It is a range of distances where an appropriate atmosphere could allow liquid water on a planet’s surface.

Yes, a small subset has been directly imaged. Most familiar exoplanet pictures are artist’s impressions.

Size, mass and spectra constrain composition, but different interiors can fit the same observations.

A convenient label for planets larger than Earth and smaller than Neptune, with no promise of Earth-like conditions.

It remains an open scientific question. A promising planet is a target for study, not a confirmed inhabited world.

The total changes as the archive accepts new confirmations. Our live statistics count the confirmed records held in the local catalogue.

The Transiting Exoplanet Survey Satellite searches for planetary transits across large areas of the sky.

Kepler monitored stars for planetary transits and transformed our understanding of how common planets are.