Is There Another Planet Like Earth?
For a long time, astronomers have been trying to find other planets that might be able to host life. While this has led to the discovery of thousands of exoplanets, finding a planet that’s just right for life can be difficult. This is because a planet has to have the right distance from its star, as well as just the right temperature to allow liquid water to exist on its surface. It also needs to have an atmosphere that’s stable enough for life to survive, but not so hot that it will boil away, or too cold that it will become ice.
Scientists Have Been Making Strides
Luckily, scientists have been making strides in the search for these “Goldilocks” planets. Using space telescopes and ground-based observatories, they have discovered over 4,000 exoplanets in the past decade. Many of these planets are rocky, and they orbit in what’s called the “habitable zone” around their stars. Now, astronomers have found another Earth-like planet in the habitable zone of a nearby star. It’s almost 95% the size of Earth, a rocky world that could host liquid water. The planet is named TOI 700 e and was discovered by NASA’s Transiting Exoplanet Survey Satellite, or TESS.
Two Planets Orbit Within the Star’s Habitable Zone
TOI 700 e is one of four known planets orbiting a small, cool star that’s about 100 light-years away. It’s joined by two other planets, TOI 700 b and TOI 700 c, that are also the size of Earth. These two planets orbit within the star’s habitable zone, but there is a difference between earth and mars. The two new planets are probably tidally locked to the star, meaning they spin only once per orbit, and always show the same side to the star. This makes them much like the Moon, which is tidally locked to our planet so that it always faces us.
TESS is Observing Thousands of Stars
In an effort to learn more about these planets, NASA’s TESS is observing thousands of stars in the nearby area, monitoring their light levels. When a planet passes in front of one of these stars, the light is dimmed. This enables the ULiege researchers to track it and confirm its existence. To date, TESS has discovered over 4,000 exoplanets, most of which are far away from our own solar system. Scientists have been especially interested in planets that have a rocky surface and orbit in the habitable zone of their stars, which is just the right distance from a star for liquid water to be present on a planet’s surface.
This is the second habitable zone planet that NASA has found in the past three years, and it’s the first that is tidally locked to its star. This is a big deal for scientists, who have been trying to determine how likely it is that they’ll find other planets that are tidally locked to their stars. It’s also the closest planet that’s tidally locked to its star yet. It’s only 3.7 million miles from its star, while Earth is 93 million miles away.