The discovery of the exoplanet 51 Pegasi b on October 6, 1995, marked a pivotal moment in astronomy, as it was the first confirmed planet orbiting a sun-like star.

This breakthrough opened the floodgates for exoplanet research, leading to the cataloging of over 6,000 diverse exoplanets, including hot Jupiters, super-Earths, and planets in multi-star systems.

The detection was achieved through observing the star's velocity changes caused by gravitational pull, using the radial velocity method with the Elodie spectrograph, which confirmed the planet's presence within ten months of observation.

51 Pegasi b is classified as a hot Jupiter, a gas giant orbiting extremely close to its star in just over four days, with atmospheric temperatures exceeding 1,000°C, challenging previous planetary formation models.

Its discovery challenged existing assumptions about planetary system architectures, as its close orbit and gaseous nature led to new theories of planetary migration.

The discovery of 51 Pegasi b defied expectations, prompting scientists to reconsider theories of planetary formation and migration, as such a planet's existence was previously thought unlikely.

This groundbreaking find was made possible by technological advancements in sensitive instruments capable of detecting stellar wobbles, making the search for exoplanets feasible.

Michel Mayor and Didier Queloz led the discovery team, with their work earning them the Nobel Prize in Physics in 2019, and was quickly confirmed by other researchers like Paul Butler and Geoff Marcy.

Historically, scientists debated whether planets were common in the universe, but modern understanding now recognizes billions of planets in the Milky Way, although true Earth analogs remain elusive.

The ongoing search aims to find Earth-like planets with similar size, mass, and temperature, with improved detection methods and dedicated instruments like Harps3 increasing the chances of discovering a true Earth twin.

The field of exoplanet research has expanded dramatically, now including diverse worlds such as mini Neptunes, lava planets, and super-Earths, though Earth-like planets remain rare and elusive.

Overall, the discovery of 51 Pegasi b marked the beginning of a new era in astronomy, sparking a scientific revolution and expanding our understanding of planetary systems and potential habitability.