The European Southern Observatory announced today the discover of yet another planet orbiting the nearby star Gliese 581. Called Gliese 581 e, It is believed to have only twice the mass of the Earth. Unfortunately, it orbits far too near its star to be hospitable to life. The observatory also reported that the previously discovered 7-Earth-mass planet ( Gliese 581 d) has had its orbit refined, to the extent that it is now seen as residing entirely inside the habitable zone of that star. Gliese 581 is approximately 20 light years from Earth. The habitable zone is the region around a star where water can exist in liquid form, thus making life far more likely on planets therein. (see ESO website for further details. www.eso.org )

Thats really great news Michael, very exciting!

A link to the story; http://www.eso.org/public/outreach/press-rel/pr-2009/pr-15-09.html

This image is an artists impression of Gliese 581 e. At this moment in time we can only imagine the beauty of these new worlds we are discovering. We are only touching the very tip of the Iceberg.



John.

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I'd certainly like to see a spectrum of Gliese 581 d. At about half the mass of Uranus, and in a much warmer part of its solar system than Uranus is in ours, its not entirely clear if its a subjovian planet, with an atmosphere dominated by hydrogen, helium, ammonia, and methane, or more like a somewhat larger version of Earth, where nitrogen, oxygen, and water predominate. Life, especially advanced forms, seem likelier in the latter case, of course. We know that all sizes of jovian planets can exist even very near a star. Where they do, its considered that they were formed in colder regions of their solar system, and migrated inward, due to gravitational interactions with dusty debris. Did Gliese 581 d migrate inward? This is not altogether clear. if it did not, a mass seven times that of the Earth seems hard to account for; Even in our system, with a larger star, and probably more material from which to form planets, seven Earths-worth of stony and metallic matter do not exist. Still, there's a great deal we don't yet know about the formation of solar systems in general, and that of Gliese 581 in particular. Michael

. . . Planeta descubierto en Gliese 581: Gliese 581e - TVN Chile 24 horas 21 04 2009


Thanks for the News Michael . . .

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Dirk,
Apart from being a very wide image(LOL), it does give you a very clear picture in your mind of how this "Habitable zone" might work for different sized stars.

Gliese 581 being smaller than our Sun, in might well have a wider habitable zone than our solar system. This increases the likelihood that small stars might have a greater chance of having planets with liquid water.

You know, when Goldie Locks visited those three bears, i bet she never expected that her name would start being used as an astronomical measurement unit...LOL

John.

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Hi Johnney!
I just thought, one single, nice, clear and fairly in size picture gives you much more information than a whole bunch of written text.
The size of this one is for me into the "reasonable and habitable zone" for SETI forum.
At least, it helps to visualize the text seen/related to before.
Cheers with that nice black ale there!
P.S.:I´ve seen the name "Goldie LOcks" related to science and space before during the "Phoenix" mission on Mars.
The mission team named something this way, but I don´t remember now what it was. Needs some research, maybe.

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Here is a NASA article from 2003 explaining about the "Goldilocks Zone".

Thousands of years ago, Stone Age man also discovered that it was easy to comminicate an idea by drawing a picture of the idea on the wall of his cave. Geee.....The idea still works today!...LOL

I like your picture Dirk.

John.

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Planet 581d has orbit suitable for life

By Kate Ravilious
NATIONAL GEOGRAPHIC NEWS

May 4, 2009

It probably wouldn't feel exactly like home. But the planet known as Gliese 581d has a lot more in common with Earth than astronomers first thought.

New measurements of the planet's orbit place it firmly in a region where conditions would be right for liquid water, and thus life as we know it, astronomer Michel Mayor, from Geneva University in Switzerland, announced recently.

“It lies in the (life-supporting) habitable zone, and it could have an ocean at its surface,” Mayor said during the European Week of Astronomy and Space Science conference at the University of Hertfordshire in England.

First discovered in 2007, Gliese 581d was originally calculated to be too far away from its host star – and therefore too cold – to support an ocean. But Mayor and colleagues now show that the extrasolar planet, or exoplanet, orbits its host in 66.8 days, putting it just inside the cool star's habitable zone.

At the same time, Mayor and colleagues announced that they have spotted a fourth planet orbiting in the Gliese 581 star system, and it's the lightest exoplanet found so far. The planet, dubbed Gliese 581e, is only about twice the mass of Earth and is the closest planet to the star, completing its orbit in about 3.15 days.

“It brings down the mass (of the lightest known exoplanet) by more than a factor of two. The previous smallest was around five Earth masses,” said Andrew Collier Cameron, an astronomer at the University of Saint Andrews in Scotland who was not involved in the find.

Gliese 581, a red dwarf star in the constellation Libra, lies about 20.5 light-years from Earth.

“In astronomical terms, it is one of our near neighbors, the 87th closest known star system to the sun,” said Carole Haswell, an astronomer at the Open University in Milton Keynes, England.

Since planets orbiting Gliese 581 are too far away to be seen directly, Mayor and colleagues originally spotted Gliese 581d by searching for tiny wobbles in the host star's motion, using the European Southern Observatory (ESO) telescope at La Silla in Chile.

Weighing in at around seven Earth masses, Gliese 581d is unlikely to be made of rocks alone, the team believes.

“We can only speculate at this stage, but it may have a rocky core, encased in an icy layer, with a liquid ocean at the surface and an atmosphere,” Mayor said.

Meanwhile, the much smaller and lighter Gliese 581e “probably doesn't look too different to Earth, except that it will be very hot, because it is so close to its host star,” said Andrew Norton, an astronomer also at the Open University.

Norton's colleague Haswell added, “It is very exciting that such a promising candidate for an Earthlike planet has been found so close to us. It means there are likely to be many more when we search further.”

And the more Earthlike planets there are, the greater the chance of discovering one that harbors life.

“I think it is only a matter of time,” Norton said. “If life really does exist elsewhere in the universe, then within the next 10 to 15 years, I expect we may see the first signs of life, via spectroscopic signals from exoplanets.”

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“I think it is only a matter of time,” Norton said. “If life really does exist elsewhere in the universe, then within the next 10 to 15 years, I expect we may see the first signs of life, via spectroscopic signals from exoplanets.”

That´s good news: we might see first signs of life outside our Solar System before arriving to Mars in 2020/2050.
Maybe even before arriving to the Moon again!

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Once one finds these earth-like planets then they need to send something up to investigate, a probe or whatever. How many light years away from earth is it? Probably too far away to even consider sending a spacecraft.

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