Earth-Like Planet That Could Sustain Life Found 575
astroengine writes "An exoplanet, 20 to 50 percent the mass of Earth, has been discovered 20 light-years away and it appears to have all the ingredients conducive to sustaining life. It has enough gravitational clout to hold onto an atmosphere and it orbits well within the 'Goldilocks Zone' of its parent star. However, it would be a very different place to Earth; it is tidally locked to its star, creating one perpetual day on the world. Interestingly, this may also boost the life-giving qualities of the exoplanet, creating stable temperatures in its atmosphere."
why do stable chances increase the likelyhood? (Score:3, Insightful)
Really.. I thought life & evolution and development thrived on change...
a little flooding, many die, some adapt
a little freezing, many die, some adapt.
more-- the 'kickstart' of inorganic->organic chemistry, presumably took some random event, a one in five gazzillion possible combination of elements, random elements- that likely would be less likely the more stable an environment it is..
nice flat temp? ya get algae & molds.... no need to improve right? why?
Re:Annddd.... (Score:5, Insightful)
His argument doesn't really hold water. Sure, once you have life that can survive on a planet it's a bitch to keep it away from anywhere, but there's no guarantee that you'll get that life to begin with.
Life (?) (Score:4, Insightful)
Re:why do stable chances increase the likelyhood? (Score:4, Insightful)
Re:why do stable chances increase the likelyhood? (Score:5, Insightful)
Venus and Mars (Score:5, Insightful)
Venus and Mars are also rocky "Earthlike" planets orbiting roughly in the habzone ("goldilocks" zone).
I'd like to see truly terrestrial planets as much as (more than, probably) the next guy, but I think the reportage here is a bit hyped. Especially given a ~3x mass, that gives it roughly 1.44x the surface gravity (and higher likelihood of a Venus-like atmosphere).
Re:Alien astronomers (Score:4, Insightful)
50% either it does or it doesn't~
remember we are using 20 yr old data (Score:5, Insightful)
Re:How can they tell its tidally locked? (Score:4, Insightful)
I don't know of any observational way to determine it at the distances involved (though there may be one), but if you make certain assumptions about the composition of the planet you can determine the maximum amount of time it takes to become tidally locked (basically, all orbiting bodies become tidally locked eventually, it's just a question of how long), and if that time is less than the time we can estimate the planet to have existed we can conclude that it SHOULD be tidally locked.
See also: http://en.wikipedia.org/wiki/Tidal_locking#Timescale [wikipedia.org]
The chances are pretty much zero (Score:1, Insightful)
We have only ONE place that we know life flourishes.
In addition, since the planet always has the same side facing the sun, the lack of tidal pumping means the crust of the planet is locked, which means no plate tectonics, which means no CO2 recycling, which means a Venus-like planet.
Sorry, but unless you can find life living with zero free water and temperatures hot enough to melt lead, fuggedaboudit.
Re:Only 20 light years??? (Score:5, Insightful)
This just goes to show you the difference in difficulty between finding a Jupiter-sized planet and an Earth-sized planet.
Wow (Score:5, Insightful)
My what exciting times we live in. Just think... it has only been around 100 years since we realized the universe is organized into galaxies. Only a few hundred since we realized that the Earth is not the center of the universe. Sometimes it is hard to have faith in the future... but discoveries like this touch that small part of me that hasn't become jaded.
Re:Only 20 light years??? (Score:3, Insightful)
Pssst. It hasn't been all that long since we discovered our first exoplanet, Jupiter sized or otherwise... 15 years or so. I think we get spoiled by the wonderful advances in science and forget how hard and how much resources it takes to keep advancing.
Re:Only 20 light years??? (Score:5, Insightful)
And while 20 light years might be small by astronomical standards, human beings haven't even been two light *seconds* away from the earth.
FWIW, Voyager 1 is about 14-15 light-hours away now.
Something to consider, though - not all radiation is the evil, hazardous, cancer-causing flesh-melting variety. Light is radiation, which is, well what they'd been using to study this thing. The shallow end of the details pool can be had here [ucolick.org](pdf).
Also, they're not just blindly poking around at random bits of cubic space - they're starting with stars, eh?
Re:Venus and Mars (Score:4, Insightful)
3 words words. Albedo, Greenhouse gasses.
The farther out you are, lower albedo and higher greenhouse gasses would be needed.
The closer in, higher albedo and lower greenhouse gasses would be needed.
Re:Time dilation woes. (Score:3, Insightful)
Re:Annddd.... (Score:5, Insightful)
This is where I stopped reading:
That's a very appropriate point to stop. To paraphrase Clarke: "When a senior scientist tells you something is impossible, they are likely to be wrong. When a senior scientist tells you something is certain, they are likely to be wrong. When a senior scientist tells you something may be possible, they are probably correct."
Re:remember we are using 20 yr old data (Score:4, Insightful)
intriguing is the fact that we are studying the planet as it was 20 years ago, not as it is present day. In roughly 100 years we've managed to screw up this planet to no end. Things could be quite different on gliese 581g at this moment and we would not know it. Assuming we could travel at the speed of light and made it there in 20 years, the inhabitants may have already turned most of the planet to concrete and smog. If it is indeed inhabited.
It's intriguing to me that anyone would call cities "screwing up" the planet. We've transformed the environment into one that is incredibly comfortable for our species to live in. There has never been a better time. The real argument that we're screwing up the planet involves this state being unsustainable, not the fact that we've achieved it.
to put 20 light years in perspective... (Score:5, Insightful)
Re:remember we are using 20 yr old data (Score:3, Insightful)
The planet doesn't care, we don't matter. In ten thousand years most of what we'd done would be gone. In ten million years most every species alive now will be extinct humans or not. That's nothing in the lifetime of this planet. The natural state of things is change and right now we're little more than an amusing bump in the grand timeline of this planet.
Stop deluding yourself into thinking we matter or that there's some actual entity called "nature" that cares what you do.
In the end, the only reason nature or what we do matters is us and our future uses of it. No one else cares and even if we remove ourselves from existence in the most dramatic way possible there won't be much impact in ten million years.
Re:Summary is wrong. (Score:4, Insightful)
Space.com gives a better summary:
http://www.space.com/scienceastronomy/earth-like-exoplanet-possibly-habitable-100929.html [space.com]
However, I think the 20% to 50% number comes from the size of the star, Gliese 581. The mass of the star is 20% to 50% of the sun's mass.
Thus far, the lowest-massed planet discovered by the radial velocity method was about 150% to 200% the mass of Earth. Discovering one as small as 20% to 50% is currently beyond the capabilities of the RV method, so the 300% to 400% figure makes a lot more sense.
Re:Annddd.... (Score:3, Insightful)
I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it,"
He contradicts himself: chances are 100%, almost sure. "Almost" is not 100%.
Plus what's up with Planet G? Planet M would have been better ;)
Re:Only 20 light years??? (Score:4, Insightful)
The GP poster neither said nor implied anything along those lines, and indeed was clearly using the "light is radiation" definition (among other ones, of course - it's not like our telescopes are limited to the visible spectrum any more). Has Slashdot fallen so low that we actually need to randomly defend the usage of the word "radiation"? I thought most of the people here had a reasonable understanding of science.
Re:Sweet (Score:3, Insightful)
We are stuck if we don't decide that we shouldn't be. If we are stuck, we need to think about what "sustainable" really means, and it means that the planet can comfortably support about 250 million people forever. Or, it can support 10 billion people for 100 years and then there is nothing left.
So, we have maybe 100 years to figure out how to get unstuck. After that, nobody is going to have a long happy life but a lot of people will have short, uncomfortable lives on a barren rock.
Re:The chances are pretty much zero (Score:3, Insightful)
We have only ONE place that we know life flourishes.
NO. We have (at the moment) one planet where we know life flourishes. On this one planet though we have an incredible diversity of places where life flourishes. At every extremity where we least expect to find life we have eventually found it. There are a LOT of places and environments where life flourishes and of the places that we know of not all are particularly "suited" to "life".
Re:And the odds of habitable aren't that great (Score:3, Insightful)
I find it hard to believe we have enough data to even begin to estimate these sorts of odds, particularly since this is the first planet we've detected that's even close to Earth-sized.
I'm also not totally convinced by your arguments that this planet would simply be another Venus, since whether the greenhouse effect is detrimental depends entirely upon the intensity of incident radiation, which is dependent on the brightness its local sun and the distance of the planet from that sun. Greenhouse on Mars would be great, greenhouse on Earth not so much.
Re:I work with 2 of the authors (Score:1, Insightful)
Actually, assuming:
* Earth-like atmosphere
* Earth-like heat absorption from the star
you would likely get a planet that goes from ~25F (but, considering greater pressure, allows for liquid water) to 135F. Pretty cold and pretty hot on either end, but not necessarily too hot or too cold.
The upper atmosphere would rotate super fast, like Venus, while the lower atmosphere would have a constant wind at the equitorial terminators at ground level (and then again, in the opposite direction, above ground level).
This would serve to mix the atmospheric heat pretty darn well!
Citation:
Joshi, Haberle, & Reynolds, "Simulations of the Atmospheres of
Synchronously Rotating Terrestrial Planets Orbiting M Dwarfs: Conditions
for Atmospheric Collapse and the Implications for Habitability", Icarus
V129, pp450-465, 1997
Prime real estate (Score:2, Insightful)
Re:Annddd.... (Score:3, Insightful)
Separately, TFS contradicts TFA. According to TFA, the planet's mass is three times larger than Earth's (I wish they'd just say three times Earth's as three times larger sounds like 1g + 3g to me)
Re:Annddd.... (Score:5, Insightful)
I'd say it doesn't hold water because... well, he simply doesn't have enough information at this point.
Indeed. From the Bad Astronomy [discovermagazine.com] blog:
However, this does not mean the planet is habitable, or even very Earthlike. It may not even have any water on it at all. For now, we can't know these things, so beware of any media breathlessly talking about life on this planet, or how we could live there.
Re:I work for the Peanut gallery (Score:3, Insightful)
It isn't clear that life only happened on Earth once. In particular, there are life communities around thermal vents in the deep ocean that very well may be the result of a completely different spark of life. For the rest of the Earth, once life gets going, it seems to become rather dominant, not leaving much opportunity for a second genesis, though how would we know if it happened?
In chemistry labs, we find that if the right basic elements are collected and put in early-Earth conditions, some of the complex molecules of life are assembled quite naturally. This is encouraging, at least.
But, 60/40 is just a complete guess, you are correct.
Re:Time to revive the orion project (Score:3, Insightful)
1000 years? That's a heck of a long time. It would be much sooner than that or not at all.
1000 years from now? I should hope that by then we'd have invented something that could move a little faster and overtake any such ship. If we're even still around, and if an enclosed human populace can survive that long at all on such a journey (my bet would be 8 or so generations before some virus wipes them out).
Don't forget that, to the 1000-years-in-the-future humans, we are the equivalent of the people just starting to invent gunpowder and paper and our 1000-years-in-the-future comrades have their own Internet, satellites, Mars-missions and quantum physics. We can just about add up, as a populace, and some highly-skilled polymaths are just getting the hang of second order equations and working out that gravity might possibly exist, while the 1000-years-in-the-future guys have atomic weapons, mappings of the human genome, synthetic foods, worldwide speed-of-light communications systems and cryogenics.
Now translate that forward another 1000 years and our puny "Ooh, we just about got two objects out of the solar system in only 40 years of travel" will be vastly overtaken by all sorts. I wouldn't be surprised if any such project was an absolute waste of time. Hell, we have two possibilities - we overtake the Voyager spacecraft ourselves in the next 100 years or so, or we never even get that far ever, at all, and die out. I think a lot of money would be placed on both sides.
But 1000 years? Please. It'd be better to wait 100 and then do it in half that time with the new advances. Human space travel is barely 50 years old itself, don't forget - you're talking about 20 times the amount of time of the entire history of spaceflight.
Re:Time to revive the orion project (Score:3, Insightful)
Similarly, pissing away billions on something that we will literally be flying past in a generation's time, waving sarcastically from the windows as the other ship would still be a generation away from even home, is a ridiculous idea. There is pretty much nothing between solar systems that is worth studying with human contact, much better investment in long-range unmanned probes until we have the technology to get to those places within a lifetime. Even the moon was seen as an easily achievable distance - it was the cost and technical problems that held back everyone from doing it earlier, not the sheer consideration of a vast distance. As with everything, there are diminishing returns and sweet spots and there is a point at which it will come down to one generation, or some other feasible number and *then* it's worth the investment and not before.
There was little point sending Voyager if we thought we would be overtaking it before it got to the outer planets, but that wasn't scientifically plausible even if we'd invested almost everything we had into the idea - the chances of us catching it within 20 years even if we could launch today are pretty damn slim. This, however, is scientifically implausible - because in several generations the chances of THAT ship being the one to get close to even the closest star and see something new is almost zero.
It's like people vowing to walk around the world - it's more than feasibly possible for one person, with only existing technology, to fashion a vehicle on the starting line that will actually overtake them before they manage to do it. Nice exercise, but in terms of achieving distance and getting to a goal, the guy building even a skateboard on the starting line will win.
Re:Time dilation woes. (Score:1, Insightful)
Bzzt. Wrong. Classical mechanics and gallilean transformations won't cut it anymore. Acceleration transforms as a 4-vector in SR (which is probably all you need for these purposes).
Check: http://en.wikipedia.org/wiki/Proper_acceleration [wikipedia.org]
Re:I work with 2 of the authors (Score:3, Insightful)
What aggravates me is the pronouncement that "it is tidally locked" rather than a "based on what we know it is likely to be tidally locked". Give it a large moon (which they couldn't detect) or a orbital resonance (which they might be able to detect) and suddenly it's not tidally locked. The things we know about this planet are its mass (within a factor of two or so) and its orbital period. And Butler's proclaiming to the Discovery channel that there's life there until someone proves otherwise, like that's the default position. And people wonder why scientists aren't taken seriously by the public. Maybe it's because too many of us can't put out a press release without saying something stupid.
Maybe they think that it doesn't matter because they'll probably be dead before we get the first spectra of this planet. Yell 'Yahtzee!' all you want, but I'm not going to believe it until I can see the dice.