Stellar astronomer and TED Senior Fellow Lucianne Walkowicz works on NASA’s Kepler mission, searching for places in the universe that could support life. So it’s worth a listen when she asks us to think carefully about Mars. In this short talk, she suggests that we stop dreaming of Mars as a place that we’ll eventually move to when we’ve messed up Earth, and to start thinking of planetary exploration and preservation of the Earth as two sides of the same goal. As she says, “The more you look for planets like Earth, the more you appreciate our own planet.”

The Earth-like planet is almost the same size as Earth, but it has a four-day year.

An international team of astronomers discovered a new planet that greatly resembles Earth in size.

The astronomers confirmed the existence of K2-415b, an exoplanet orbiting an M dwarf star some 72 light-years away from Earth, according to a press release.

## Discovering an alien world

The team behind the discovery set out to look for stars that could be suitable hosts for planets that may harbor life.

In a paper available in the preprint server arXiv, they explain how they used a method called radial velocity. Essentially, the gravity of orbiting exoplanets causes small wobbles in the light emitted by the planet’s host star. These wobbles change the color of the light, allowing astronomers to detect them from Earth.

Radial velocity is one of several methods astronomers use to detect exoplanets — any planet that is not part of our solar system. Other methods include direct imaging and the transit method, which measures the periodic drop in light of a distant star as an exoplanet passes between the star and an observatory’s field of view.