7 Terrestrial Planets Found Orbiting Within the Habitable Zone of a Nearby Star

NASA scientists released one of the great scientific discoveries of the 21st Century today: There are 7 Earthlike planets circling a star 39 light years from Earth, in the Constellation Aquarius.

From the perspective of a person (or alien) standing on the surface of one of the planets, some of the other worlds would appear larger than the moon in the Earth's sky.

Google has marked the Earth-shattering discovery with a Doodle, featuring the seven planets squeezing into view on the earth's telescope. https://g.co/doodle/ybt9k4

TRAPPIST-1 stands for Transiting Planets and Planetesimals Small Telescope. The discovery is a small, dim star in the constellation Aquarius, less than 40 light-years from Earth, or 235 trillion miles away, according to Nasa and the Belgian-led research team who announced its discovery on Wednesday.

Six of TRAPPIST-1's "exoplanets" lie in a temperate zone where surface temperatures range from zero to 100C.

Of these, at least three are thought to be capable of having liquid oceans, greatly increasing the likelihood of life. No other star system known contains such a large number of Earth-sized and probably rocky planets.

All are about the same size as Earth or Venus, or slightly smaller. Because the parent star is so dim, the planets are warmed gently despite having orbits much smaller than that of Mercury, the planet closest to our sun.

Scientists said they need to study the atmospheres before determining whether these rocky, terrestrial planets could support life forms.

Gazing skyward from one of the seven, it would be possible to see the geological features, oceans and clouds of planetary neighbors.

The relatively cool star at the center of this system would shine 200 times dimmer than our sun, a perpetual twilight as we know it. And the star would glow red - maybe salmon-colored, the researchers speculate.