When scientists search for alien planets, they get a special thrill when they find one that seems to reflect our own world back to us.
TOI 700 d is the newest member of that elite club. The planet was discovered courtesy of NASA’s Transiting Exoplanet Survey Satellite, or TESS, as one of three worlds in a distant solar system. Unlike its neighbors — and the vast majority of planets scientists have identified so far — it seems to be about the same size as Earth and to orbit its star at a distance that would allow water to remain liquid on its surface. The discovery was announced here on Jan. 6 at the 235th meeting of the American Astronomical Society.
As an Earth-size planet in its star’s habitable zone, TOI 700 d is a big deal for scientists. “We really want to understand the question, could life form on these planets around very small stars? And this is kind of a nice big step towards that goal,” Joseph Rodriguez, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Massachusetts, told Space.com. “We’re nowhere near it yet and we’re talking, probably, decades, if not much, much longer to answer this question. but we’re making steps towards arguably one of the biggest questions in science — and not just science but philosophy, religion and a lot of other things.”
Read more: space