On Wednesday, August 24, scientists announced the discovery of Proxima b — an Earth-like planet in the habitable zone of Proxima Centauri.

Pale Red Dot — “an outreach project to show to the public how scientists are working to address a major question that could affect us all, namely are there Earth-like planets around the nearest stars? — made the discovery using the Ultraviolet and Visual Echelle Spectrograph (UVES) and the High Accuracy Radial velocity Planet Searcher (HARPS) telescope-mounted instruments. Data from these tools at the European Southern Observatory in Chile provided scientists with the evidence that led to the discovery.

According to, Proxima b is approximately 1.3 times more massive than Earth, suggesting to researchers that this alien world is a rocky planet. The planet’s discovery is exciting to astrobiologists because Proxima b is in the middle of the habitable zone — the ideal distance from its star for liquid water to exist on the planet’s surface. Although the planet orbits tightly around its star, Proxima Centauri is a red dwarf, which is considerably cooler than our sun.

Proxima Centauri Habitable Zone

(Credit: ESO/M. Kornmesser/G. Coleman)

This isn’t the first Earth-like exoplanet discovered, but it is the closest. Researchers estimate that Proxima b is mere 4.2 light-years from our solar system.

The research that led to Proxima b’s discovery is published in the journal Nature.