SURELY NOT ALONE
The European Southern Observatory reports that the most Earthlike planet has been found orbiting another star.
It has about 1.5 times the Earth’s diameter, and five times its mass. This makes it the smallest extrasolar planet yet found - two other planets have already been found orbiting that star (with 15 and 8 times Earth’s mass).
Its star, Gliese 581, is a red dwarf - meaning it’s smaller and cooler than the Sun. It orbits its star much closer than the Earth orbits the Sun and stays about 11 million km from Gliese 581, while the Earth is 150 million km from the Sun.
Gliese 581 is cooler than the Sun - so at this distance the planet would actually be very temperate: models show it would be between 0 and 40 Celsius ;-)
That is warm enough for water to be in liquid state, hence what we may have here is a terrestrial planet with liquid water on its surface!
Its still not yet known if the planet (coded Gliese 581c) is dry, or covered in oceans, or even if it’s rocky like the Earth. This planet is Earthlike, but not Earth! The surface gravity is more than twice that of Earth’s and we do not yet know what the atmosphere may be like.
One of the major goals of science is to find out if life has arisen and evolved elsewhere in the Universe and this has surely been one of my major mental quests.
Until 1995 we weren’t even sure if any other stars had planets. Now we know of hundreds, and as the technology gets better, we can find smaller and smaller ones. We’re right on the verge of being able to find ones just like Earth - and I have always claimed that most certainly we are not alone in the universe.
Getting an image of it is currently not possible: at a distance of 20 or so light years, Gliese 581 one of the closest stars in the sky, but still far too distant to separate the planet from the star.
It has about 1.5 times the Earth’s diameter, and five times its mass. This makes it the smallest extrasolar planet yet found - two other planets have already been found orbiting that star (with 15 and 8 times Earth’s mass).
Its star, Gliese 581, is a red dwarf - meaning it’s smaller and cooler than the Sun. It orbits its star much closer than the Earth orbits the Sun and stays about 11 million km from Gliese 581, while the Earth is 150 million km from the Sun.
Gliese 581 is cooler than the Sun - so at this distance the planet would actually be very temperate: models show it would be between 0 and 40 Celsius ;-)
That is warm enough for water to be in liquid state, hence what we may have here is a terrestrial planet with liquid water on its surface!
Its still not yet known if the planet (coded Gliese 581c) is dry, or covered in oceans, or even if it’s rocky like the Earth. This planet is Earthlike, but not Earth! The surface gravity is more than twice that of Earth’s and we do not yet know what the atmosphere may be like.
One of the major goals of science is to find out if life has arisen and evolved elsewhere in the Universe and this has surely been one of my major mental quests.
Until 1995 we weren’t even sure if any other stars had planets. Now we know of hundreds, and as the technology gets better, we can find smaller and smaller ones. We’re right on the verge of being able to find ones just like Earth - and I have always claimed that most certainly we are not alone in the universe.
Getting an image of it is currently not possible: at a distance of 20 or so light years, Gliese 581 one of the closest stars in the sky, but still far too distant to separate the planet from the star.
Artist's impression of the planetary system around the red dwarf Gliese 581. Using the instrument HARPS on the ESO 3.6-m telescope, astronomers have uncovered 3 planets, all of relative low-mass: 5, 8 and 15 Earth masses. The five Earth-mass planet (seen in foreground - Gliese 581 c) makes a full orbit around the star in 13 days, the other two in 5 (the blue, Neptunian-like planet - Gliese 581 b) and 84 days (the most remote one, Gliese 581 d). (c) ESO Labels: Never Ending Story
posted by Universo Mental at 13:54
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