The Historic Discovery of Exoplanets: 25 Years Later
Written on
Chapter 1: A New Era in Astronomy
There was an era when humanity thought that Earth encompassed the whole universe. As our understanding of the cosmos evolved, curiosity about the existence of planets orbiting other stars grew. Today, we can definitively say that such planets exist, and this realization began precisely 25 years ago. On October 6, 1995, astronomers revealed the discovery of the first exoplanet circling a sun-like star, named 51 Pegasi b, a finding that significantly transformed our approach to studying the universe.
I remember vividly how, as an enthusiastic 11-year-old, I watched the news covering this monumental announcement. Within just a week, another research team validated the discovery, solidifying 51 Pegasi b's historical significance. It was a momentous occasion, and its implications have only become more apparent as we now find ourselves in a remarkable era of exoplanet exploration. The discovery of 51 Pegasi b even led to the awarding of the Nobel Prize in Physics to its discoverers in 2019.
51 Pegasi b orbits the star 51 Pegasi, located around 50 light-years from our planet. Michel Mayor and Didier Queloz from the University of Geneva identified 51 Pegasi b through what is known today as the radial velocity technique. A highly sensitive spectroscope aimed at the star detected minute changes in velocity, approximately 70 meters per second. This oscillation was confirmed to be caused by the gravitational pull of the exoplanet, 51 Pegasi b. Although this foundational technique is still used to discover some exoplanets, most recent detections are made using the transit method, as employed by the Kepler telescope and the newer TESS satellite.
The researchers ascertained that 51 Pegasi b is a gas giant, roughly half the size of Jupiter, which led to its new designation. In 2014, the International Astronomical Union (IAU) initiated a project to assign proper names to significant stars and exoplanets, moving away from the cumbersome naming conventions typically used. The star was named Helvetios, while the planet was dubbed Dimidium, derived from Latin meaning “half.”
Section 1.1: The Significance of 51 Pegasi b
While 51 Pegasi b was not the first celestial body discovered outside our solar system, it was the first to be recognized as a "true" planet. The initial detections of exoplanets occurred in 1992 when astronomers observed two possibly destroyed worlds orbiting a pulsar known as PSR B1257+12. However, 51 Pegasi is a main-sequence star akin to our sun, making its planet significantly more intriguing. This exoplanet has a close orbit to its star, resulting in temperatures exceeding 1,000 degrees Fahrenheit. This was contradictory to our understanding of solar system formation in 1995, yet we have since learned that "hot Jupiters" are far more common than previously thought.
The discovery of the first exoplanet | The 2019 Nobel Prize in Physics - YouTube
The discovery of Dimidium has set us on a course toward a deeper comprehension of the universe. Consider the advancements made in the past 25 years: in 1995, we were aware of a single exoplanet; today, we have cataloged over 4,000. One such planet is even situated in the Proxima Centauri system. What will the next 25 years reveal? Will we find planets in other galaxies or those capable of supporting extraterrestrial life? Only time will tell.
A Discovery that Forever Changed Us | Exoplanet Radio ep 14 - YouTube
Now read: Astronomers Find ‘Pi Planet’ With 3.14-Day Orbit, Astronomers May Have Detected a Planet in Another Galaxy, Scientists Find First-Ever Planet Orbiting Dead Star.