Editing Interstellar travel (section)

== Discovery of Earth-like planets ==
On August 24, 2016, Earth-size exoplanet [[Proxima Centauri b]] orbiting in the habitable zone of [[Proxima Centauri]], 4.2 light-years away, was announced. This is the nearest known [[List of potentially habitable exoplanets|potentially-habitable exoplanet]] outside our Solar System.

In February 2017, NASA announced that its [[Spitzer Space Telescope]] had revealed seven Earth-size planets in the [[TRAPPIST-1]] system orbiting an ultra-cool dwarf star 40 light-years away from the Solar System.<ref>{{cite web |date=22 February 2017 |title=Release 17-015: NASA Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star |url=https://www.nasa.gov/press-release/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around |website=[[NASA]] |access-date=25 February 2017 |archive-date=5 March 2017 |archive-url=https://web.archive.org/web/20170305055703/https://www.nasa.gov/press-release/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around/ |url-status=live }}</ref> Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water. The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside the Solar System. All of these seven planets could have liquid water – the key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.