Earthlike Planet Orbiting Nearby Star

The Bad Astronomer writes "Astronomers in Europe have announced the discovery of a planet with only 5 times the Earth's mass, orbiting a red dwarf star 20 light years away. It orbits the star so closely that it only takes 13 days to go around... but the star is so cool that the temperature of the planet is between 0 and 40 Celsius. At this temperature there could be liquid water. Models indicate the planet is either rocky like the Earth or covered in an ocean. While it's not known if there actually is liquid water on the planet, this is a really big discovery, and indicates that we are getting ever closer to finding another Earth orbiting an alien star."

Comments

When do tickets go on sale?

[644bd346996]

So, the temperature range indicates that it can probably be made hospitable for humans. Sure, we might have to bring a lot of our own oxygen and water to start with, but otherwise, we just need a colony ship. And, of course, the gravity is pretty strong (2.25 Gs) so we will have trouble with that. And, it being so close to the star, there might be a big radiation problem, forcing humans to go underground. But that wouldn't be too bad, because it would make gravity a bit less of a problem.

What I think is the coolest thing is that this is the smallest extrasolar planet found so far. We are getting close to being able to detect earth-sized planets. Once we do, I think the number of potentially colonizable planets will go up quite a bit.

This is worth sending a probe.

[plasmacutter]

We are currently developing technologies which allow a maximum speed of 0.6 X the speed of light.

if you create a probe with an ion drive and send it off in the next 10 years we could be looking at surveys of the planet in question by 2070.

Re:How long to get there?

[Wonko the Sane]

So that would take us 20 years to get there travelling at the speed of light 20 years by the perspective of an observer on earth, instantaneously by the perspective of the traveller.

Re:Uninhabital new worlds

[SignalX]

It is good to see everyone has a positive attitude for space exploration. I must assume that, in your opinion, there is no good reason to go to Mars or the Moon?

Also remember that were you got the information on gravitational pull and the atmosphere for this planet is speculative at best.
1) 2.25 times that of our own gravitational pull would not be ideal for us to live but, it doesn't mean nothing could live there. I pull 2.25g's with my car on a dry skid pad, I have not died yet.
2) Really?
3) Yes the planet is closer to its sun that ours, but if this planet is like ours, the atmosphere filters out most of the radiation. The star closest to them does not spit out the magnitude of radiation that ours does due to its size.
4) If there is atmosphere like ours with water in it, it will hold some of the heat as it passes out of its suns rays and therefore should be just as turbulent.

Also some things to think about:

Even if the planet is 2 times as big as our planet, it could be spinning faster than ours. This would help off set the gravitational pull on our bodies at the surface.

No one is saying this is a planet to colonize, but with some of our technology and determination, it could be a waypoint in the stars for us to refuel and grab water before we continue our adventures further into space.

Just my two cents,

-X

Probably not tidally locked.

[AJWM]

I haven't run any mathematical models, but given that there's a Neptune-mass (15 Earth mass) planet orbiting inside this planet's orbit (5.4 day orbit vs 13 day orbit), I'd guess that that's enough of a disruption to at least prevent a 1:1 tidal lock. There may be some kind of lock at another resonance (eg Mercury's 2:3 lock) but that would allow for rotation relative to the star and thus more-even heating.

2.25 gees is uncomfortable but tolerable (carry someone your own weight piggyback and you're almost there), and largely irrelevant to any water-dwelling critters.

However, the larger problem -- that I didn't see any of the articles explicitly raise -- it that there's likely a Venus-like greenhouse with the temperature much hotter than the 0-40C based on the equilibrium temperature of a rocky body at that distance from the primary. We can hope not, but we'd need a reason why not.

Based on our system, anything Venus-size or larger has a thick atmosphere, except Earth, and Earth is an anomaly because it got whacked by something massive (Mars mass) late in its formation, blowing most of the volatiles -- and the material that makes up the Moon -- off the planet altogether. (However, such late-stage super-impacts may be not all that unusual; it could explain some other oddities of our system, such as Uranus's tilt.)

Re:Probably not tidally locked.

[niktemadur]

I read last week that the sensitivity of new instruments can now detect the chemical fingerprints of extrasolar planetary atmospheres. They should get on the ball with this baby as of yesterday. However, I don't know if 2.5 Earth masses is big enough for measurement, as many of these extrasolar planets have 5-6 or more Jupiter masses, and the instruments are probably pointed at these monsters.

I'm a sucker for this kind of news, so I'll be waiting until somebody can measure and report results with a major presence of either CO2, nitrogen, methane, whatever's there. But then again, Gliese 581 is a red dwarf, has it gone through a red giant stage? If so, any atmosphere may have been blasted into deep space.

Then again, maybe atmospheres can regenerate through the leaking of gases from beneath the planetary crust, volcanic-style, and with 2.5 G's, I would imagine it wouldn't drift into space on its' own very easily. If so, a red dwarf may be extremely stable, creating an exponentially longer window for life on systems like these than with a main-sequence system like our own. But obviously, this is completely speculative territory.

Re:Probably not tidally locked.

[Rei]

1) Red dwarfs are main sequence stars; they're not, and never have been, giants. Smaller stars form white dwarfs, while larger giants form neutron stars or black holes (or sometimes Wolf-Rayet stars)
2) Yes, most planets do leak gasses, although the rates and gasses vary greatly, as does what is retained.
3) Red dwarfs are extremely stable. They burn their fuel extremely slowly. Gliese 581 will be burning long after the sun given up.

Re:How long to get there?

[BiggerIsBetter]

Two words: inertial dampers.

Two other words: Relativity, and Acceleration.

I've read[1] that if we accelerate consistently at 1G we'll reach 0.77 C in 1 year. However, as we continue to accelerate closer to C, we get more and more relativistic and things get screwy... screwy to the point that I'll estimate it would take about 6 years (that's 6 rocket years, not earth observer years) to get there, with 1G accel and 1G deccel. So, human travel would be extremely feasible.

While a probe could accelerate much harder, I figure it would still take 50 years or so to get results from a probe to confirm it's worth sending people.

1. http://www2.corepower.com:8080/~relfaq/rocket.html

Re:How long to get there?

[shaitand]

We don't have a people shortage, or even a crazy people shortage. Skip the probe and send volunteers. Promise enough funds to support their families for life and you will get cheap volunteers from third world nations that are throwing babies into rivers due to overpopulation. You can't lose.

Re:quick maths on gravity

[mrbiggenes]

The star is only about 47%-56% enriched as our Sun in elements heavier than hydrogen, so it stands to reason that any planets that formed around the star are similarly deficient in heavy elements/metals. See the following web page about the star, but keep in mind it has not been updated with this latest planetary information:

http://www.solstation.com/stars/gl581.htm

Semi-inhabital new worlds

[stfvon007]

What about people that gain weight going from ~ 120lbs to say, 260. As its done over time, the body adapts and they are still able to walk around and live normally (although it does have adverse health effects) I think it is possible for people to adapt, but it will not be comfortable, especially for the first generation, and they will probably live a lot shorter. If this doesn't work however, It may however be possible to genetically engineer humans to live on high-G environments, increasing muscle mass, and bone density and thickness, as well as cardiovascular improvements.

I am aware of one experiment of putting someone in a high-G centerfuge and subjecting him to 1.5G's. The experiment was terminated early, due to the participant having a mild heart attack. Keep in mind, the participant wasn't given time to acclimate to the new environment gradually, and the experiment was short in duration, lasting only about a week, as it was designed more towards seeing if a high-G environment could help astronauts overcome loss of muscle mass and bone decalcification faster than normal after returning to earth, rather than colonization of a high-G environment.

Re:How long to get there?

[Warg! The Orcs!!]

I wanted to mod you up but couldn't resist asking a question.

What about space dust? INAA (I'm not an astro-physicist)but I don't think that the main problem is a lack of speed. Eventually we will work out how to go faster and faster. For me the problem is those little bits of rock and grit in the way. Even at 0.75C travelling in the not-quite empty vastness of space would be like standing in front of a machine gun going full-on.