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Life on planet Gliese?

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http://www.foxnews.com/scitech/2010...und-earth-size-planet-percent-astronomer-say/

I just think this is kinda cool. Let's go there. :). Okay that's a little difficult at this time. Who doesn't think earth-like planets are cool? Big huge gas giants are boring. We want to see Vulcans and such. I'll post the article for your entertainment.

An Earth-size planet has been spotted orbiting a nearby star at a distance that would makes it not too hot and not too cold — comfortable enough for life to exist, researchers announced today (Sept. 29).

If confirmed, the exoplanet, named Gliese 581g, would be the first Earth-like world found residing in a star's habitable zone — a region where a planet's temperature could sustain liquid water on its surface.

And the planet's discoverers are optimistic about the prospects for finding life there.

"Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent," said Steven Vogt, a professor of astronomy and astrophysics at the University of California, Santa Cruz, during a press briefing today. "I have almost no doubt about it."

His colleague, Paul Butler of the Carnegie Institution of Washington, in Washington, D.C., wasn't willing to put a number on the odds of life, though he admitted he's optimistic.

"It's both an incremental and monumental discovery," Sara Seager, an astrophysicist at the Massachusetts Institute of Technology, told SPACE.com. Incremental because the method used to find Gliese 581g already has found several planets (all super-Earths, more massive than our own world) outside their stars' habitable zone, along with non-Earth-like planets within the habitable zone.

"It really is monumental if you accept this as the first Earth-like planet ever found in the star's habitable zone," said Seager, who was not directly involved in the discovery.

Vogt, Butler and their colleagues will detail the planet finding in the Astrophysical Journal.

The newfound planet joins more than 400 other alien worlds known to date. Most are huge gas giants, though several are just a few times the mass of Earth.

Stellar tugs

Gliese 581g is one of two new worlds the team discovered orbiting the red dwarf star Gliese 581, bumping that nearby star's family of planets to six. The other newfound planet, Gliese 581f, is outside the habitable zone, researchers said.

The star is located 20 light-years from Earth in the constellation Libra. One light-year is about 6 trillion miles (10 trillion km).

Red dwarf stars are about 50 times dimmer than our sun. Since these stars are so much cooler, their planets can orbit much closer to them and still remain in the habitable zone.

Estimates suggest Gliese 581g is 0.15 astronomical units from its star, close enough to its star to be able to complete an orbit in just under 37 days. One astronomical unit is the average distance between the Earth and sun, which is approximately 93 million miles (150 million km).

The Gliese 581 planet system now vaguely resembles our own, with six worlds orbiting their star in nearly circular paths.

With support from the National Science Foundation and NASA, the scientists — members of the Lick-Carnegie Exoplanet Survey — collected 11 years of radial velocity data on the star. This method looks at a star's tiny movements due to the gravitational tug from orbiting bodies.

The subtle tugs let researchers estimate the planet's mass and orbital period, how long it takes to circle its star.

Gliese 581g has a mass three to four times Earth's, the researchers estimated. From the mass and size, they said the world is probably a rocky planet with enough gravity to hold onto an atmosphere.

Just as Mercury is locked facing the sun, the planet is tidally locked to its star, so that one side basks in perpetual daylight, while the other side remains in darkness. This locked configuration helps to stabilize the planet's surface climate, Vogt said.

"Any emerging life forms would have a wide range of stable climates to choose from and to evolve around, depending on their longitude," Vogt said, suggesting that life forms that like it hot would just scoot toward the light side of that line while forms with polar-bear-like preferences would move toward the dark side.

Between blazing heat on the star-facing side and freezing cold on the dark side, the average surface temperature may range from 24 degrees below zero to 10 degrees Fahrenheit (minus 31 to minus 12 degrees Celsius), the researchers said.

>Are you sure?

Supposedly habitable worlds have been found and later discredited, so what makes this one such a breakthrough?

There's still a chance that further observations will dismiss this planet, also. But over the years, the radial velocity method has become more precise, the researchers point out in their journal article.

In addition, the researchers didn't make some of the unrealistic assumptions made in the past, Seager said.

For instance, another planet orbiting Gliese 581 (the planet Gliese 581c) also had been considered to have temperatures suitable for life, but in making those calculations, the researchers had come up with an "unrealistic" estimate for the amount of energy the planet reflected, Seager pointed out. That type of estimate wasn't made for this discovery.

"We're looking at this one as basically the tip of the iceberg, and we're expecting more to be found," Seager said.

One way to make this a reality, according to study researchers, would be "to build dedicated 6- to 8-meter-class Automated Planet Finder telescopes, one in each hemisphere," they wrote.

The telescopes — or "light buckets" as Seager referred to them — would be dedicated to spying on the nearby stars thought to potentially host Earth-like planets in their habitable zones. The result would be inexpensive and probably would reveal many other nearby potentially habitable planets, the researchers wrote.

Beyond the roughly 100 nearest stars to Earth, there are billions upon billions of stars in the Milky Way, and with that in mind, the researchers suggest tens of billions of potentially habitable planets may exist, waiting to be found.

Planets like Gliese 581g that are tidally locked and orbit the habitable zone of red dwarfs have a high probability of harboring life, the researchers suggest.

Earth once supported harsh conditions, the researchers point out. And since red dwarfs are relatively "immortal" living hundreds of billions of years (many times the current age of the universe), combined with the fact that conditions stay so stable on a tidally locked planet, there's a good chance that if life were to get a toe-hold it would be able to adapt to those conditions and possibly take off, Butler said.
 
20 light years is rather a long way away though. How far has Pioneer travelled? Nowhere near a light year I'll wager.

EDIT: October, 2009 - speed of the spacecraft indicates it is about to reach 100 AUs from our Sun - or approx 9.3 billion miles. [2] Another comparison is that the nearest star, trinary Alpha Centauri's Proxima companion, is of approx 271,000 AUs distance.[11]

EDIT2: 1LY = about 63,241.1 astronomical units
 
Earth is not the only planet in our solar systems "habitable" zone, both Venus and Mars are in that region and yet we do not find any life on those planets.

33% odds are still good odds though.
 
20 light years is rather a long way away though. How far has Pioneer travelled? Nowhere near a light year I'll wager.

EDIT: October, 2009 - speed of the spacecraft indicates it is about to reach 100 AUs from our Sun - or approx 9.3 billion miles. [2] Another comparison is that the nearest star, trinary Alpha Centauri's Proxima companion, is of approx 271,000 AUs distance.[11]

EDIT2: 1LY = about 63,241.1 astronomical units

better get to it quick then!
 
That was my thought exactly J-man when I read about it. The astronomer in the article seems to think the opposite though - that stable conditions make it easier for life to adapt. My gut feeling is that having a near constant temperature is bad for the many chemical reactions needed to get life started.
 
Earth is not the only planet in our solar systems "habitable" zone, both Venus and Mars are in that region and yet we do not find any life on those planets.
My thoughts too, and that picture with the Gliese planet's orbit imposed on our solar system puts it almost in the same orbit as Venus. However, this quote are present in some of the news reports

has announced the discovery of an Earth-sized planet (three times the mass of Earth) orbiting a nearby star at a distance that places it squarely in the middle of the star's "habitable zone," where liquid water could exist on the planet's surface
(my bolding). The star's a red dwarf.
 
To be clear, we can't say for certain that life didn't arise on Mars or Venus, all we can say is that we don't think we see it there now. Not quite the same thing.
 
Earth is not the only planet in our solar systems "habitable" zone, both Venus and Mars are in that region and yet we do not find any life on those planets.
Venus is on the very front edge of the habitable zone, Earth in the center, and Mars about 3/4ths out. There would be life on Mars right now if the planet wasn't so small and the core didn't cool as fast as it did. Once it lost its magnetosphere, advanced life had no chance.
 
20 light years is rather a long way away though. How far has Pioneer travelled? Nowhere near a light year I'll wager.

EDIT: October, 2009 - speed of the spacecraft indicates it is about to reach 100 AUs from our Sun - or approx 9.3 billion miles. [2] Another comparison is that the nearest star, trinary Alpha Centauri's Proxima companion, is of approx 271,000 AUs distance.[11]

EDIT2: 1LY = about 63,241.1 astronomical units

There was informal-ish CFC discussion around here on the topic a while back, but it's a clear conclusion that we could build (unmanned) spacecraft far faster than the Voyagers or Pioneers or anything previous, if that was the actual aim (not going photographing/flybyes around our own solar system or anything). Now, it would take a lot of work, some newer tech, and we're not talking magical speeds here, so 20 light years still becomes 100+ years even at a fraction of c, but it'd be doable.

Gliese system continues to be very interesting which is awesome though...couple years back with the other exoplanets discovered there it already was a major find and finding more is just great.
 
How fast would a 1g space ship get there, from its own frame and from Earth's frame?

My knowledge of special relativity only deals with frames moving at constant velocity.


EDIT: I asked wolfram alpha but it only knows newtonian mechanics (boo). Will ask my professors next week when I get back.
 
Ok slightly off topic but how fast would a spacecraft have to go to escape the solar systems gravity and go into free space? I have almost no knowledge of physics so i dont know if thats possible.

But if a spacecraft was traveling freely through space and another solar system was moving closer towards it wouldnt it make the trip faster?

For that matter i dont know how fast a galactic year is, that is how long a star takes to revolve around the center of the galaxy. If its really long it might not make much of a difference.

Sorry if what im saying doesnt make sense i really no next to nothing of space physics.
 
Not sure what you mean peter grimes. A 1g spaceship starts at 0 velocity, accelerates for half the journey at 10ms-2 (which creates a perfect simulation of earth's gravity) and then slows down at 10ms^-2 until it lands softly at its intended target. The accelerations are, given in the frame which moves at whatever instantaneous velocity the spaceship has at that point.

A galactic year is very very long, 1/4 a billion earth years or something like that. Not that it matters, because the spaceship has its own velocity, plus the velocity of the earth plus the velocity of the sun. You can easily ignore the centrifugal acceleration. Its the same idea as throwing a ball vertically up in a car - it just goes up and down from where you are, and doesn't go shooting to the back of the care at 70mph.
 
I think the fact that it's a red dwarf increases the likelihood of life, because the system would be so much older than Sol. An older system increases the odds. Life could have started before the planet became tidally locked, too, and evolution would have allowed life to continue as the planet slowed.

edit: my bad, the star is assumed to be about 2 billion years old.

Obviously, odds are against there being life. But having a planet like this within 20 ly is pretty cool. It's the 82nd closest planet to earth, and the numbers involved are big. There're over 1200 stars within 50 ly of us, which is where some of our radio signals have reached.

All I know is that if there's life, I'd want humanity to have as much tech as possible before we bump into it. Having tech always makes the difference. The best way to speed up tech development is to push for a more educated populace (at the personal level) and to focus consumer spending on R&D to create technological feedback cycles.
 
Problem with red dwarfs is that their energy output vary enormously. Their activity can decrease a lot and they can also emit large flares. Not good for life.

A problem with tidal lock is that the night side is really cold and that all the water the planet has could freeze up there.
 
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