It means that Gliese 581g is the right distance from its sun to be in the habitable zone, able to sustain liquid water and with enough gravity to retain an atmosphere.
Some evidence suggests that the very earliest Mars was watery, but modelers can't explain how its climate could have sustained liquid water.
The two inner planets are too close to their host star to be in the "habitable-zone," which is the zone around a star where a planet could sustain liquid water on its surface – a key ingredient for life as we know it.
All seven planets are temperate, meaning that under the right atmospheric and geologic conditions, they could sustain liquid water.
When Earth was born 4.6 billion years ago, it was too hot to sustain liquid water on its surface.
It turns out that about 22percentt of all Sun-like stars boast a planet that's at the right orbital distance to sustain liquid water on its surface.
Such a weak star would not have been able to sustain liquid water on Earth's surface, and thus life should not have been able to develop.
A planet that is neither too hot nor too cold to sustain liquid water on its surface is generally considered to have the potential for life. .
Still, Mr. Caldecott, says, while the issuance of government bonds or multilateral institutional development debt would be helpful, the more basic need is to develop self-sustaining, liquid markets in corporate green bonds.
Nature's perfect food still harbors many secrets, but new work shows how one protein helps mammary glands get calorie-rich fat into the life-sustaining liquid.
We have been squandering and polluting this precious resource and are now in need of finding cost competitive newer technologies for reclaiming this valuable life-sustaining liquid.
