A distant planet has been dubbed Earth 2.0 after Nasa scientists said it was “the closest thing that we have” to a planet that could sustain life as Earth does.
Whether you see the discovery as one of the most exciting moments in the advancement of the human race or believe we’ll look back and realise it was the opening scene of a terrifying sci-fi Armageddon film turned reality, there is no denying that Kepler-452b – to give it its official title – is huge news.
Earth 2.0 orbits a star similar to our sun and is a ‘Goldilocks’ planet, meaning it orbits at a distance perfect for liquid water to exist – not too hot and not too cold. The presence of water could mean it’s hospitable to life.
John Grunsfeld, associate administrator for Nasa's Science Mission Directorate in Washington, said: "Today we're announcing the discovery of an exoplanet that as far as we can tell is a pretty close cousin of Earth. It's the closest so far. It's Earth 2.0."
"Today the Earth is a little less lonely because there's a new kid on the block," said Jon Jenkins, Kepler data analysis lead at Nasa's Ames Research Center in California, adding, “It is the closest thing that we have to another place that somebody might call home.”
So just what do we know about Kepler-452b?
IT'S VERY SIMILAR TO EARTH
The size, length of its years and surface conditions are all estimated to be extremely similar to ours. It takes 385 days to orbit its star, just 20 days more than we do. For context, Venus – sometimes the closest planet to us – takes around 225 days.
Jon Jenkins said: "If you travelled to this star with an arkful of plants [...] the plants would photosynthesise just perfectly fine. It would feel a lot like home from the standpoint of the sunshine.”
THERE'S A CHANCE IT HOSTS LIFE
It has been in the habitable zone – the perfect distance from its star – for billions of years, which Nasa scientists say means it's possible it hosts life or could have at some point as it could have water on its surface. The star it orbits, Kepler 452, is slightly bigger than our own sun, but could sustain plant life which in turn makes the air breathable.
“It is six billion years old. That is considerable opportunity for life to arise on its surface and its oceans should all the necessary conditions for life have appeared on this planet,” according to Jon Jenkins.
IT'S BIGGER THAN US
Earth 2.0’s larger size means it’s thought to have twice the gravitational pull of Earth, but humans could potentially survive and “adapt” to the heavier pull, even becoming “more stocky”.
Jon Jenkins said: "Humans are built to do this kind of thing. The human body has an amazing ability to repair itself - so over time, humans could adapt." What this means for the lifeforms potentially already there, we’re not sure.
IT TOOK YEARS TO CONFIRM
Scientists have to date discovered 12 potentially habitable exoplanets, including Earth 2.0 (the only one of the 12 to be confirmed as a planet), after analysing four years’ worth of data from Nasa's Kepler telescope.
The Kepler telescope detects tiny dips in the brightness of stars as planets pass between them and Earth and once these are spotted, other techniques are used to verify exoplanets, such as changes in the motion of other suns. The entire mission cost $600million to fund.
IT COULD BE A GLIMPSE OF THE FUTURE
Kepler 452, the star Earth 2.0 orbits, is around 1.5 billion years older than our own sun and could in theory show us what Earth could be like that far down the line, as aging stars grow in size and energy, thus giving out more heat.
"If Kepler-452b is indeed a rocky planet, its location vis-a-vis its star could mean that it is just entering a runaway greenhouse phase of its climate history. The increasing energy from its aging sun might be heating the surface and evaporating any oceans. The water vapour would be lost from the planet forever," explained Kepler scientist Dr Doug Caldwell.
"Kepler-452b could be experiencing now what the Earth will undergo more than a billion years from now, as the Sun ages and grows brighter."
WE CAN'T SEE A PICTURE OF IT
It's far too far away for us right now, but according to John Grunsfeld, improved technology may one day enable scientists to “make the first primitive maps” and show “whether they have oceans, clouds, perhaps even seasons”.
YOU'RE PROBABLY NOT GOING
Kepler-452b is 1,400 light years away. A light year is the distance a beam of light can travel in a year. To put this in context, light from the Sun - 149,600,000 km away from Earth – takes around eight minutes to reach us, or 0.00001585 of a light year.
Nasa's New Horizon probe is currently the fastest craft we have at around 36,373 mph. At that speed, it would take us 25.8 million years to get there.
"We won't be going to this planet but our children's children's children might be," Jeff Coughlin, a Kepler research scientist, said. "It's a very long term goal but a very exciting one."
Images: NASA / Rex Features