Exoplanets are planets that orbit stars outside our solar system. Since the first confirmed discovery in 1992, thousands have been found—ranging from massive gas giants to rocky Earth-like planets.

• Transit Method – detecting dips in a star’s brightness as a planet crosses in front.
• Radial Velocity – measuring wobbles in a star due to gravitational tugs from orbiting planets.
• Direct Imaging – rare, but it involves capturing actual images of exoplanets using powerful telescopes.

Scientists look for Earth-like conditions such as presence of water, breathable atmosphere, and habitable temperatures in the so-called Goldilocks Zone—not too hot, not too cold.

• Kepler-452b – dubbed “Earth’s cousin”, a super-Earth in the habitable zone.
• TRAPPIST-1 System – seven Earth-sized planets, three in the habitable zone.
• Proxima b – an Earth-like planet orbiting our nearest stellar neighbor, Proxima Centauri.

Future missions like the James Webb Space Telescope (JWST) and Ariel aim to study the atmospheres of these alien worlds and possibly detect bio-signatures.