Discovering an Earth-Sized Planet in the Habitable Zone %

On the 6th of January 2020, National Aeronautics and Space Administration brought the good news of the discovery of planet ‘TOI 700 d’ which exists in its stars habitable zone. The planet was discovered by Emily Gilbert and her colleagues from the University of Chicago using NASA’s Transiting Exoplanet Survey Satellite (TESS) and it is found to be only 31 parsecs (unit of measurement for large distances of astronomical objects) from planet Earth. Since its launch in 2018, TESS has found over 1500 stars so far; however, most of them were far from the habitable zone of our planet.

At the moment, astronomers only know that the planet is 1.2 times the size of Earth and it orbits its star once every 37 days. If scientists are able to measure its mass, they will be able to find its density which could help determine its topography: whether it is rocky like Earth or gassy like Neptune. Despite that, astronomers suggest that even if the planet turns out to have rocky landscapes like Earth, it still wouldn’t have similar properties to that of Earth. TOI 700 d’s star is significantly smaller and dimmer than the Sun, meaning it gets less light in comparison to Earth. However, since it is in the habitable zone, after all, the planet could have liquid water on its surface or in its atmosphere.

The discovery of TOI 700 d is significant to astronomers and astrophysicists as it is easier for them to study the properties of nearby stars and planets rather than distant ones. The study of TOI 700 d could bring scientists closer to finding alternative habitable planets for humans or find hints of extraterrestrial life in our solar system.