Good news! Earth will stay habitable for another 1.75 billion years
By Scott Sutherland | Geekquinox – Thu, 19 Sep, 2013
Taking measurements for our potential new home?
According to a new study published in the journal Astrobiology, we have a minimum of 1.75 billion years before the Earth becomes uninhabitable, and if we can make it out of the solar system before then, the 'super-Earth' planet Gliese 581d would be a great place to relocate.
With all the planets that astronomers have been spotting orbiting around other stars, there's been a lot of talk about a star's 'habitable zone' . This is the band of space surrounding a star that's kind of a 'Goldilocks zone', where the temperature is just right — not too hot or too cold — so that a planet could have liquid water. A planet being in this habitable zone doesn't guarantee that it's going to have life on it, but we have a pretty good example of that with our very own planet, Earth.
You might think that since Earth is so well-suited for life that we're right smack-dab in the middle of our Sun's 'Goldilocks zone', but we're not. Looking at the image to the right, whether we use a more 'forgiving' version of the zone (light green) or a more 'restrictive' one (dark green), either way Earth is closer to the inner edge of it. It's obvious that we're in a good position right now, of course, but according to the latest research, it's not always going to stay that way. This is because the position of the 'Goldilocks zone' depends on the output from the star, and that changes as the star ages.
As our sun gets older, it will get hotter, and this will push its habitable zone further out. Somewhere between 1.75 and 3.25 billion years from now, Earth will slip into the position that Venus now holds, and our home planet will heat up to the point where all the liquid water boils off the surface. Given the age of our planet, that means life here has a minimum of about 6 billion years.
That's pretty nice, given that some planets out there aren't as lucky. Kepler 22b, a super-Earth about 600 light away, apparently has roughly 6 billion years at the most. However, there are others that are even better off. Another 'super-Earth' called Gliese 581d, which orbits a small, cool star around 20 light years from here, is expected to be habitable for at least 40 billion years!
So, if we're still around when Earth becomes boiling-hot, we might want to check in to see if our neighbours can put us up for awhile.
By Scott Sutherland | Geekquinox – Thu, 19 Sep, 2013
Taking measurements for our potential new home?
According to a new study published in the journal Astrobiology, we have a minimum of 1.75 billion years before the Earth becomes uninhabitable, and if we can make it out of the solar system before then, the 'super-Earth' planet Gliese 581d would be a great place to relocate.
With all the planets that astronomers have been spotting orbiting around other stars, there's been a lot of talk about a star's 'habitable zone' . This is the band of space surrounding a star that's kind of a 'Goldilocks zone', where the temperature is just right — not too hot or too cold — so that a planet could have liquid water. A planet being in this habitable zone doesn't guarantee that it's going to have life on it, but we have a pretty good example of that with our very own planet, Earth.
As our sun gets older, it will get hotter, and this will push its habitable zone further out. Somewhere between 1.75 and 3.25 billion years from now, Earth will slip into the position that Venus now holds, and our home planet will heat up to the point where all the liquid water boils off the surface. Given the age of our planet, that means life here has a minimum of about 6 billion years.
That's pretty nice, given that some planets out there aren't as lucky. Kepler 22b, a super-Earth about 600 light away, apparently has roughly 6 billion years at the most. However, there are others that are even better off. Another 'super-Earth' called Gliese 581d, which orbits a small, cool star around 20 light years from here, is expected to be habitable for at least 40 billion years!
So, if we're still around when Earth becomes boiling-hot, we might want to check in to see if our neighbours can put us up for awhile.
