Somewhere in the vast chasm of space, a planet maintaining life like Earth could exist! These planets are known as “exo-planets”, or planets which orbit stars outside of our solar system. Ever since 1995, when the first exoplanet was confirmed to orbit around a sun-like star, NASA has been hard at work at finding more and more of these extraordinary wonders. Currently, NASA has found an amazing 4,055 confirmed exoplanets and continues to constantly search for more. With their advanced technology and a myriad of methods to find them, NASA is sure to uncover the mysterious reaches of other galaxies in no time.

Currently, NASA’s method for classifying exo-planets is divided into five categories; Neptune-like, Super-Earth, Gas Giant, Terrestrial, and Unknown. Neptune-like exoplanets are similar to the planets Uranus or Neptune in our solar system, while Super-Earth exoplanets are exotic due to their strange size and composition. Super-Earth planets are bigger than Earth but lighter than Gas-Giants like Neptune and can be made of gas, rock, or both! Gas Giants are similar to Jupiter and Saturn in our solar system, and Terrestrial planets resemble Mercury, Venus, and Mars with their iron-rich core. The final type, Unknown, is unclassified because they don’t quite fit in any of the categories, and are only six of the total 4,055 confirmed discoveries. 

There are four main ways in which these exoplanets are found, with the most effective being through Transit, followed by Radial Velocity, Microlensing, and Imaging. Transit is when a planet passes between its star and an observer, which dims the star’s light a noticeable amount. Radial Velocity is also light-based but involves the stars changing color because of the planets orbiting them. Microlensing involves light being bent and being focused by gravity, which lets people from Earth observe the planet, and Imaging involves removing the light from the planets’ stars so that only the planets are visible in pictures.

With all of these different discovery methods, it’s no surprise that NASA has found 159 exoplanets so far in 2019 alone. But, if the goal is to find a planet like Earth, which can sustain life, then let’s focus on just the most recently discovered Terrestrial exo-planets since they’re the most similar to our planet. According to NASA’s exoplanet archive, only 5 of the 159 discovered exo-planets are Terrestrial; EPIC 201497682 b, EPIC 201833600 c, EPIC 206215704 b, EPIC 206317286 b, and L 98-59 b. Talk about a mouthful! Tedious names aside, each planet was found through Transit, and resemble Earth with their mass. Of course, while not much is known about the individual terrain for these planets and none of them seem to be life-sustaining like Earth, it’s still fascinating to know that they exist, since they show how endless space can be.

Each year, many students in Oakton High-school are intrigued by the Astronomy course, where students can experience the wonders of the universe through the planetarium. Filled with a sense of wonder and passion for space, perhaps some of these students could become the astrophysicists and astronomers who finally discover an Earth-like exoplanet, and pave the path to our new home.