The discovery of exoplanets—planets that orbit stars outside our solar system—has revolutionized our understanding of the universe and sparked a quest to find other worlds that might support life. Since the first confirmed discovery in 1992, scientists have identified thousands of exoplanets, uncovering a diverse range of planets that challenge what we know about planet formation and the potential for life beyond Earth.
The first confirmed exoplanets were found orbiting a pulsar, a type of dead star, by astronomers Aleksander Wolszczan and Dale Frail. These planets, known as PSR B1257+12 b, c, and d, were not Earth-like, but their discovery proved that planets exist beyond our solar system. This breakthrough paved the way for more searches using advanced technologies and techniques.
In 1995, astronomers Michel Mayor and Didier Queloz made the first discovery of an exoplanet orbiting a main-sequence star, similar to our Sun. The planet, called 51 Pegasi b, is a gas giant similar to Jupiter but much closer to its star. This discovery earned the pair the Nobel Prize in Physics in 2019.
Exoplanets are discovered using several methods. The most common is the transit method, where astronomers observe a star’s light dimming as a planet passes in front of it. The radial velocity method measures small changes in a star’s motion caused by the gravitational pull of an orbiting planet. Other techniques, such as direct imaging and gravitational microlensing, have also been successful in identifying distant planets.
One of the most significant missions in exoplanet discovery was NASA’s Kepler Space Telescope, which launched in 2009. Kepler detected over 2,600 confirmed exoplanets, greatly expanding our catalog of known planets. More recent missions, like TESS (Transiting Exoplanet Survey Satellite), continue to search for planets around nearby stars.
Exoplanets come in a wide variety of sizes, compositions, and orbits, from hot Jupiters that orbit close to their stars to Earth-like planets in the habitable zone, where conditions might support liquid water and potentially life. The discovery of these planets raises profound questions about the possibility of life beyond Earth and the uniqueness of our solar system.
The study of exoplanets remains one of the most exciting frontiers in astronomy, offering the possibility of finding another Earth-like world and expanding humanity’s understanding of our place in the universe.