Exoplanet discovery: Five facts you didn't know about Nasa’s new solar system

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Nasa's announcement of the discovery of a new solar system including seven exoplanets that resemble earth is the subject of today's Google Doodle.

Here are five things you need to know about their momentous findings.

Three of the seven planets found circling the TRAPPIST-1 dwarf star appear to be rocky in nature and to host surface temperatures capable of sustaining liquid water and, therefore, oceans.

By extension, this means that their atmospheric conditions would potentially be able to sustain alien life, representing “the holy grail for planet-hunting astronomers”.

Scientists will begin investigating the molecular make-up of the exoplanets. The Hubble telescope, for instance, will reveal whether there is methane or water in the air. If sufficient amounts of oxygen are detected, this would “strongly” indicate the presence of biological activity taking place.

They hope to have a definitive answer within a decade.

Marginally larger than Jupiter and 39 light years away, TRAPPIST-1 is relatively young and will still be in its infancy once our own sun has exhausted its fuel and been destroyed – an alarming notion.

By contrast, the TRAPPIST-1 star burns hydrogen so slowly that it will live on for another 10 trillion years, 700 times longer than our universe and ample time to evolve organic life, according to Ignas Snellen of the Leiden Observatory in the Netherlands.

Nasa researchers using the Trappist robotic telescope (hence the name) from Chile's Atacama desert discovered the solar system by observing the passage of planets as they drifted by host stars.

In passing, celestial bodies obscure a small amount of light and cast shadows, a phenomenon that serves to indicate their size, mass and shape. Having traced 34 such transits using a Spitzer telescope, the scientists were able to confirm the presence of the seven spheres.

A human being situated on one of the new planets would experience 200 times less light than they are used to from our own sun, the difference likened to that between watching a sunset and midday glare.

Dimmer than earth, the planets would nevertheless be just as warm as they experience much the same heat energy as we do from our sun, albeit transmitted as infrared rays.

A person looking up at the new solar system’s sun from terra firma on TRAPPIST-1 would see it as salmon pink in colour and larger than our own. “The spectacle would be beautiful,” said Amaury Triaud, one of the scientists involved in the research.

Whether the inhabitants of such a world would have eyes similar to own remains to be seen - they could have evolved entirely new means of seeing to cope with the different light exposure.

Exciting as the new discovery is, astronomers say there could still be an additional 40 billion potentially habitable worlds sitting just inside our galaxy, along the Milky Way.

The first exoplanet was found in 1992. Since then, over 3,500 new worlds have been located across 2,675 star systems.

As technologies continue to advance and become ever-more sophisticated - the forthcoming James Webb and Giant Magellan space telescopes are both expected to reveal a wealth of new information - the possibilities of finding more seem infinite.