In the past several years, astronomers have found a large and growing number of Earth-sized exoplanets orbiting distant stars. Some are in the habitable zones of their stars, where temperatures might allow liquid water to exist on their surfaces. That is exciting in itself, but Proxima Centauri b is of particular interest since it’s orbiting the closest star to our sun, only 4.2 light-years away. Proxima b, the closest alien planet we know, may be even more Earth-like than we thought https://t.co/YOmLoKsHEe — Nayef Al-Rodhan (@SustainHistory) May 30, 2020 Its confirmation underscores current findings that such worlds are common in our galaxy. Proxima Centauri b is very similar in size to Earth, with a mass of 1.17 Earth masses. It orbits its star in only 11.2 days, in contrast to our Earth’s year-long orbit around our sun. That means Proxima Centauri b is a lot closer to its star than Earth is to the sun. But, because the star is a red dwarf – much smaller and cooler than our sun – its orbit is indeed within the habitable zone of Proxima Centauri. Interestingly, Proxima Centauri b receives about the same amount of solar energy from its star that Earth does from our sun. An Earth-sized planet orbiting Proxima Centauri and a paleolithic nursery for great white sharks – watch today’s #ScientiFix with @MohanaBasu for the top science stories of this week. https://t.co/2SYHvJG8af — Shekhar Gupta (@ShekharGupta) May 31, 2020 “We were already very happy with the performance of HARPS, which has been responsible for discovering hundreds of exoplanets over the last 17 years,” said Francesco Pepe, a professor in the Astronomy Department in UNIGE’s Faculty of Science in a statement. “We’re really pleased that ESPRESSO can produce even better measurements, and it’s gratifying and just reward for the teamwork lasting nearly 10 years.” Alejandro Suarez Mascareño, said: “Confirming the existence of Proxima b was an important task, and it’s one of the most interesting planets known in the solar neighbourhood.” Although Proxima b is about 20 times closer to its star than the Earth is to the Sun, it receives comparable amounts of energy. If there is liquid form on the planet, it could harbour life, but researchers said there is still much to be done before that can be confirmed.