We have found 6,000 planets, but we still cannot read their atmospheres
Astronomers have confirmed over 6,000 worlds outside our solar system, yet much of this data remains a mystery. This lecture explores how scientists use spectroscopy and quantum mechanics to decode the chemical fingerprints of distant planets and overcome the challenge of observing worlds we cannot see directly.
In this Royal Institution Discourse, Professor Jonathan Tennyson explains the difficulty of studying exoplanets, where extreme temperatures create complex spectral signatures and parent stars often outshine their planets. While direct imaging has been used for fewer than 100 planets, most discoveries rely on indirect methods like the transit method, which detects a star's dimming as a planet passes in front of it.
The field is expanding rapidly; following the 1995 discovery of 51 Pegasi b, the 5,000-planet milestone was reached in 2022, and the count has now breached 6,000. Future missions like the Nancy Grace Roman Space Telescope may revolutionize this search, potentially uncovering 100,000 worlds by examining unexplored regions of the Milky Way, including the galactic central bulge.
Source: 6,000 planets discovered — and we still can't read their atmospheres | with Jonathan Tennyson
