Gliese 581 is an unassuming red dwarf star. Situated in the constellation Libra and just over 20 light years from our home system, it is located in the northeast part of Constellation Libra, the Scales -- northeast of Delta Librae, north of Gamma Librae and Graffias (Beta Scorpii), and southwest of Epsilon (Yed Posterior) and Delta (Yed Prior) Ophiuchi, and Mu, Epsilon, and Alpha (Unukalhai) Serpentis. It's too dim to see by the unaided eye.
It's your average red-dwarf star. Red dwarf stars are tiny. They glow red. They're cool. And they're numerous. And sometimes they're belligerant - sometimes they have a tendancy to shoot off superflares that more then dwarf their dimunitive magnitudes and sizes. In the star system closest to our own, Alpha Centauri, the component that 's currently closest to our solar system is Proxima Centauri. It's a red dwarf. And too dim to see.
Gliese 581, or HO Librae, is not as unassuming as it seems. In 2005, researchs discovered it wasn't a lonely little red dwarf star. A planet orbits the tiny star at an impossibly close distance, whipping around its parent sun every 5.366 days. It's probably not a nice place, and not much is known about it. But it is known that it is 17 times the mass of Earth, or about the mass of Neptune, and it probably is about as hot as Mercury (the planet, not the element.)
Gliese 581 has one more world. This one's a lot more exciting.
European astronomers have spotted what they say is the most Earth-like planet yet outside our solar system, with balmy temperatures that could support water and, potentially, life.
They have not directly seen the planet, orbiting a red dwarf star called Gliese 581. But measurements of the star suggest that a planet not much larger than the Earth is pulling on it, the researchers say in a letter to the editor of the journal Astronomy and Astrophysics.
"This one is the first one that is at the same time probably rocky, with water, and in a zone close to the star where the water could exist in liquid form," said Stephane Udry of the Geneva Observatory in Switzerland, who led the study.
"We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius (32 to 104 degrees F), and water would thus be liquid."
The new planet is about five times heavier than Earth. Its discoverers aren't certain if it is rocky like Earth or if its a frozen ice ball with liquid water on the surface. If it is rocky like Earth, which is what the prevailing theory proposes, it has a diameter about 1 1/2 times bigger than our planet. If it is an iceball, as Mayor suggests, it would be even bigger.
Based on theory, 581 c should have an atmosphere, but what's in that atmosphere is still a mystery and if it's too thick that could make the planet's surface temperature too hot, Mayor said.
However, the research team believes the average temperature to be somewhere between 32 and 104 degrees and that set off celebrations among astronomers.
Until now, all 220 planets astronomers have found outside our solar system have had the "Goldilocks problem." They've been too hot, too cold or just plain too big and gaseous, like uninhabitable Jupiter.
Now this planet COULD be like Earth. It could have oceans and continents. But it'd be significantly different. For one thing, it whips around its parent star every 13 days. At that distance from its star it may be tidally locked--- it may not even rotate on its axis, or may be in resonance with the larger planet that orbits sunward. This means that, like Mercury, its day may be longer then its year (which would look bizarre from the surface...at times the sun would move BACKWARDS in the sky.) Red light may not be conducive for photosynthesis as we know it. However the timing of this discovery is pretty cool as the current issue of Astrobiology Journal has a series of articles about the potential habitability of worlds orbiting M-type stars. Plants may be black in color on such a world, responding to the infrared.
You'll also feel pretty heavy here. Olds88 did the math. At the surface gravity would be 2.2 times the gravity on Earth. Falls would be deadly for a human, who would be in great discomfort. And mountains would likely be lower and it's likely oceans would be far more extensive.
All speculation, of course.
For the record, I'm not an astronomer. I'm a budding sci-fi writer and long time fan. But I like my stories to have some basis in science, so I educated myself all about this and have done so for years, plus I've had a long time interest in the stars and potentially getting off this rock and going on to see other rocks. I wish the Greys would come for me some days. I'd even tolerate the probings.
And also for the record, Olds88 broke the story on the site. In fact, the second I saw it in my Google News, I came right here prepared to gush about it, and he had already done so. He deserves big kudos. Plus he also worked out some of the math (as linked above) and also deserves Kudos.
At any rate, Gliese 581 c was #1. At present, the COROT telescope is scanning the skies and next year Lords of Kobol willing, NASA will send up the Kepler Telescope that will scan the skies and look for worlds like the one discovered recently. And ten years down the line, both the ESA and NASA are both planning space-based telescopes that may actually image these worlds. I'm excited.
This isn't an excuse, of course, to not fix the world we're already on. Our world is unique---to us. There's only one planet with Humanity on it. But we may just learn that there's not just one world with life on it, and Earth is not all that unique to the Universe in the grand scheme of things.
And also for what it's worth, I think this could revitalize the moribund space industry here on Earth. Imagine, a universe full of worlds that support life. Even life somewhat (biochemically) like us. Imagine that it could inspire more and more kids to study science and math, and with a Democratic administration, encourage them to. It's a good time to be a nerd.
But Can We Go There?
Well? Can we?
Anything's possible. Although at present, there's no real way to go faster then light like in the movies or on the television, Miguel Alcubierre's work notwithstanding.
Just to show my nerd cred, I actually bought a book titled The Starflight Handbook. I'm always inventing new universes and writing stories (or parts of stories, committement to one thing is a problem of mine) and I figured I wanted some science to research.
One of the more intriguing ideas (and a great way to rid the Earth of nuclear weapons) was Project Orion (note that NASA has a current Project Orion---they are not the same thing.) Project Orion, or Nuclear Pulse Propulsion, could be built soon. During the engineering study in the 1960s, it was speculated it could be built in the 1970s. The project died, having been managed by too many agencies and the military, and so on, in much the way that many government projects die. However it has its flaws (mainly, the use of nuclear explosions to propel the ship) The top speed that a Project Orion starship could make is likely 10 percent of the speed of light. Meaning, it would take a ship about 200 years to reach this potentially habitable world, which would mean we'd have to send a generation ship or a genetically diverse group in suspended animation. And that brings up all sorts of other issues!
There's still a group of people that want to use Orion-type ships to explore the solar system.
NASA's got some ideas too.
At any rate, anything's possible. We have the capability to save our world, and perhaps in a few generations, send a colony or two to others outside of our own solar system. And our perception of the universe may have changed today with Gliese 581 c, orbiting a tiny red dwarf star only 20 light years away.