Exploring Exoplanets: From Detection to Habitability

Exoplanets, or extrasolar planets, are planets outside our solar system. First discovered in the 1990s, over 4,000 have been found. They range from gas giants larger than Jupiter to rocky worlds smaller than Earth.

Astronomers use various methods to detect exoplanets. The transit method observes starlight dimming when a planet crosses its star. Radial velocity measures stellar wobble due to a planet's gravitational pull. Direct imaging captures visual evidence of planets.

NASA's Kepler telescope revolutionized exoplanet discovery. Launched in 2009, it confirmed over 2,600 exoplanets by monitoring starlight for transits, greatly expanding our catalog of known alien worlds.

Some exoplanets, known as rogue planets, do not orbit stars. They wander the galaxy alone, possibly ejected from their original solar systems. These elusive objects challenge our understanding of planetary formation and existence.

Astronomers can analyze exoplanet atmospheres using spectroscopy, dissecting light to reveal molecular signatures. This helps identify potentially habitable worlds by detecting water vapor, oxygen, and other life-suggesting elements.

The habitable zone, where liquid water could exist, is crucial for life as we know it. The discovery of exoplanets within this zone, like those in the TRAPPIST-1 system, fuels the search for extraterrestrial life.

Future telescopes, like the James Webb Space Telescope and the European Extremely Large Telescope, promise to peer closer into exoplanet atmospheres, potentially identifying biosignatures that could indicate the presence of life beyond Earth.

On the exoplanet WASP-76b, it rains molten iron due to extreme temperatures, making it one of the most extreme weather systems known.