What is the star systems the like our solar system in which life can exist ?
Question:
Answer:
The new planet wjere life is thought to be feasible orbits Gliese 581, one of the nearest 100 stars to us, 20.4 light years away.
The new planet was found on 23rd April 2007 by a team led by Stephane Udry of Geneva University, The observatory they used was high in the Chilean Andes, where good viewing conditions would be available.
It is in the constellation Libra. It is the 87th closest star system to us. Its star (a Red Dwarf) is too faint to be seen with the naked eye, however. Its magnitude is 11.56.
The planet is called Glese 581c. What is unusual about it, amongst the 237 planets we have found orbiting other stars is
a) it is a rocky terrestrial planet not a gas giant
b) it is in the habitable zone i.e. with a temperature range at which water would be a liquid not ice. This is felt to be essential if it is to harbour life.
c) it has a radius 1.5 times that of earth (and a mass 5 x earth), the smallest yet,
(d) It orbits very close to its star (as the star, a Red Dwarf, is much cooler than our Sun, the planet needs to be nearer in to be warm enough to be habitable) and its year is a mere 13 Earth days in length.
There are two other planets in the same stellar system, one even further in (Gliese 581 b) a Neptune-sized planet of 17 Earth masses found in 2005 and one further out (Gliese 581 d) a planet of 8 Earth masses found in 2007.
The big question marks are:
(a) it is big enough to retain an atmosphere but is it breathable by humans?
(b) does it actually have (a plentiful supply of) water?
(c) how would we get there? (our present fastest rockets available would take 300,000 years)
(d) is the planet gravitationally locked to ts star, such that the same side of it always faces the star?
Many of the questions people will inevitably ask can only be answered when we can send an unmanned probe there. Meanwhile other planets will be found even nearer to us. (We know of a planet 10.5 light years away around Epsilon Eridani (the 9th nearest star) and 3 around Gliese 876, 15 light years away.)
One promising aspect of Gliese 581 is that it is both younger than our Sun (4.3 billion years) and it will outlive the Sun as it burns its hydrogen fuel up more slowly, so any colony we might one day establish there would not have to up sticks and be on the move again for a long time.
However a propulsion method that would get colonists there in less than half a human lifetime would need to be developed first, before colonisation is practical. And the practical problems of transporting enough fuel, food, water and air, for a crew of ten or more would need to be solved too. No easy undertaking!
Wilhelm Gliese was a German astronomer, best known for the Gliese Catalogue of Nearby Stars that he compiled.
Life is pretty hardy and, if its out there at all, its probably out there in abundance and in forms we can only theorize about. But-if you mean systems where humans could live? Any system with solid planets. We are able to adapt ourselves to any enviroment. Check Nasa.gov- they've been finding planets all over the place the last couple of years! In fact, if you look in Yahoo science news, there was something in there last Thurs about a possibly Earth-like planet they found.
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