At the scale of the galaxy, one could almost say that it is the next door. « TOI 700 d », a planet similar to Earth, has been detected « only » 100 light years away from us.
This observation is the first carried out by NASA’s “planet hunter”, the TESS (“Transiting Exoplant Survey Satellite”) space telescope. Its radars have located one of the few stars that are in a habitable situation.
Of a size comparable to the Earth (only 20% larger), “TOI 700 d” indeed revolves around a sun at a distance which would prevent too extreme temperatures and allow the formation of water. It completes its revolution in 37 days, and receives 86% of the supplied energy that the Sun sends to Earth, according to a statement from the US space agency .
Scientists have not yet established with precision the conditions on the planet’s surface. However, they made several very different assumptions. According to one of them, “TOI 700 d” could be covered with oceans, with a cloudy face constantly exposed to its star. In another scenario, the star, whipped by the winds, would be devoid of water.
Future observations will thus have to determine « the presence of the atmosphere, and if so, its composition, » said NASA . Ditto for the constitution, solid, gaseous or both, of this planet.
In any case, an astronaut is not yet ready to set foot on “TOI 700 d”, even if the planet turns out to be habitable. The 9.460 billion kilometers that separate us from it would require several hundreds of thousands of years of travel by traveling in our current spacecraft .
The fastest, the American space probe New Horizons, does indeed travel “only” 14.3 kilometers per second. Launched in 2006, it overtook Pluto in 2015.