Extrasolar Planet Could Harbor Life

BlueMorpho writes with a link to a Space.com article about a recently discovered extrasolar planet that may be able to harbor 'life as we know it.' Orbiting around the star Gliese 581 is a small rocky ball that might have the same liquid ocean and drifting continent configuration we're familiar with. The find may be unique in all of space exploration as this planet appears to be within a habitable band of temperatures for life, and is categorically not a gas giant. "The bottom line is exciting ...The conditions for life could be there, but is life itself? As yet, there's no way to know unless the planet has spawned beings that are at least as clever as we are. As part of the SETI Institute's Project Phoenix, we twice aimed large antennas in the direction of Gliese 581, hoping to pick up a signal that would bespeak technology ... Neither search turned up a signal."

Comments

Oh my god, it's full of dupes.

[ColonelPanic]

This is categorically amazing! Gliese 581 has not one, but *two* planets capable of sustaining life as we know it!

The best neighbors...

[Chysn]

...are the ones you can't see even with a telescope.

The trouble is

[zappepcs]

"The bottom line is exciting ...The conditions for life could be there, but is life itself? As yet, there's no way to know unless the planet has spawned beings that are at least as clever as we are. As part of the SETI Institute's Project Phoenix, we twice aimed large antennas in the direction of Gliese 581, hoping to pick up a signal that would bespeak technology ... Neither search turned up a signal." emphasis mine

The trouble is that despite the planet's title sounding like a science fiction title, the former residents of Gliese 581 were at least as clever as we are, and the planet is currently recovering from a complete nuclear winter...

Re:The trouble is

[steveo777]

Probability of another earth-like planet? Prohibitive.
1. Our sun's positioning in this galaxy is basically perfect. We're between two of the 'arms' of the milky way. Meaning we're nestled safely away from the gravitational chaos of other stars that may want to rip us out of our orbit around the center of our galaxy. So that rules out many places in our galaxy. Not saying there isn't a chance. I'm just saying that theoretically, the planets in there may be screwed some time in the future. Most other galaxy styles don't have a 'safe harbor' like this.

2.Earth itself has so many favorable factors for it that it is astounding. The tilt of our axis makes for an optimal environment for life across our whole planet. I remember reading that many astrologers estimate that just a half a degree either way and we'd have much larger ice caps or a band of uninhabitable desert. Our elliptical, almost circular, orbit keeps us in the most comfortable spot. A million miles either way and we'd be toastier or colder. Life could still exist, but it would be less than 'ideal'.
As I understand it, our ferrous core spinning at slightly different speed creates our Van Alen Belts to protect from solar wind.
We have an asteroid belt that has protected us from undoubtedly billions of asteroids over the millennial of Earths existence.
Our tidal locked moon pulls on the oceans causing the Earth to continue spinning at a proper speed to maintain life.

How' that? When you consider all this, and the probabilities being of this happening elsewhere (or just 'enough')... you can pretty well give up hope. But there isn't any fun in that! I'm all for looking for hospitable planets. This universe is fascinating. What a waste to not explore?!

Re:The trouble is

[toganet]

Look out, your anthropomorphism is showing. True, it is unlikely that humans would have resulted from adaptation to an environment different than our own. But that's how adaptation works.

We may very well find "life" on planets that fall far outside your narrow definition of it -- but, as Dr. McCoy said, "not as we know it".

Re:The trouble is

[BakaHoushi]

Alpha Centauri is NOT "some obscure planet." Honestly, if you Earthlings can't be bothered to take an interest in local politics, I've no sympathy at all.

Re:The trouble is

[fyngyrz]

Doesn't SETI focus on a specific band of the EM spectrum that is not polluted by solar radiation and thus an obvious place for any sentient beings on another world to broadcast a signal that would allow themselves to be found?

The follow up question being: Are we broadcasting such a signal at that frequency?

The answers are, respectively, yes, and no. Though we have made a heck of a lot of noise at other frequencies, and the earliest of those signals are very roughly about 100 light-years out by now. They would be extremely weak and difficult to detect, though with a large enough space-based antenna system, it is certainly doable if they listen in the right direction. Signals that have gotten about 50 light years out are much more powerful; they've reached fewer stars, of course.

I suspect that our "window" of using RF transmissions through the air will close within another century or so. There are better, more reliable things available to us such as fiber; almost incomprehensibly higher bandwidth by virtue of one fiber being able to lie next to another, not so easy when using RF, better availability, much more difficult to interfere with, more efficient in terms of energy required in use... RF just doesn't make a huge amount of sense for broadcast, and this is becoming more so every day. And I say that with a certain degree of regret, being an extra-class ham radio operator who grew up with the romance - no, really, I'm serious, romance! - of radio signals fading in and out from all over the world.

Seems like if we're assuming whatever sentient beings out there think like us and thus we can deduce what they would do to be found, that only makes sense if it's something we would do in order to be found by other sentient life forms.

It is what we'd do - we're not doing it for political reasons, not scientific or technical reasons. It has been proposed over and over that we broadcast; and has been turned down every time. The question is, do we want to invite visitors? It is one thing to be curious to see if you have neighbors, and to learn the answer without disturbing them or letting them know we're here; it is entirely something else to let them know we're here, or to invite them over - as unlikely as that seems given what we know of physics today. Considering that it is unlikely, it would be all the more intimidating if someone from the Sirius system, just to pluck one out of a hat, heard our signal and a day after they heard it there, they showed up here. The question is, what would they show up with if their physics are that good? All they really need is the ability to shove a few large rocks in our direction and they could go home snickering about those silly primates that used to live on Sol 3... that concerns a lot of people. Some earth species are quite aggressive and territorial, and man is one of them. Looking at our own behavior, it doesn't seem too conservative to think that the same might apply to someone else. So the politics are knotty.

Re:The trouble is

[hubie]

I think you need to recheck some of your facts.

Our solar system moves in and out of the spiral arms as well as up and down through the galactic plane. We go through the galactic plane about every 35 million years, and through the spiral arms about every 100 million years. Some postulate that these timescales coincide with various mass extinctions that occurred.

The axial tilt of the Earth changes all the time. The tilt angle varies between 22 and 25 degrees over a period of about 41000 years. There is also precession of the orbit that happens on a 22000 year timescale. The changing tilt angle changes the severity of the seasons (length of seasons, ice ages, etc.), but it doesn't have anything to say about whether the planet could harbor life.

There isn't anything magical about our molten core and magnetosphere. We usually expect large rocky planets to have them, so we find it unusual if a planet doesn't have a magnetosphere.

I wouldn't say that the asteroid belt has protected us. The asteroid belt is basically a planet that either didn't form, or didn't survive. Its existence is probably one of the biggest threats to our survival on this planet. It is a race to see whether a large asteroid or comet hits our planet and wipes us out. Nobody doubts that it will happen again in the future; we just don't know when it will.

The Moon actually causes a drag on the planet that is slowing down the Earth rotation. I don't recall hearing what an ideal rotation rate for the Earth is to sustain life.

Once one gets their head around how many stars there are in just our own galaxy, many people consider it a given that there is life all around in the galaxy. Even if you take the most pessimistic odds for life to develop, once you multiply that by the number of stars out there it would seem to be very likely. The most famous statement of this is the Drake Equation. Of course, once you consider the extremely large distances between any two stars it is easy to come to the conclusion that all this life will not come in contact with each other (the intelligent life, that is).

Space/Genetic Exploration

[spentmiles]

I wonder what we'll find fist: a) A planet as inhabitable by us as Earth. b) A way to genetically modify humans to adapt to currently inhospitable conditions. Maybe we'll be able to breath sulfurous air, like that found on XJ93832, which is otherwise a resort planet. I've been doing my own experiments with a homemade dutch oven. My subject/wife is quite an innovator. I think she's been altered at the genetic level several times.

Re:Space/Genetic Exploration

[MontyApollo]

I have wondered how well we could adapt to even an Earth like planet in terms of infectious agents like bacteria and viruses. Would we just have to accept higher mortality rates until our immune systems adapted over time?

The medical science and technology might the easy part compared to interstellar travel though.

Re:Space/Genetic Exploration

[RsG]

It's not terribly likely that alien pathogens could harm us. Remember that most plain old fashioned terrestrial diseases are only able to infect a limited variety of hosts. HIV originated in chimps (our closest living evolutionary relatives), rabies is limited to mammals, the flu (which is versatile by viral standards) is primarily limited to mammals and birds, etc. Even diseases like malaria which spend parts of their life cycle in very different hosts (us and mosquitoes) are fairly specialized.

Try and imagine dutch elm disease making the transition from trees to humans. Then remember that both host organisms are terrestrial - we're more closely related to trees than we would be to any alien. It's not totally impossible that some alien bacteria could, by some chance, find the human body hospitable (or vice versa), but it isn't very probable.

Plus, the human immune system has a habit of attacking anything remotely foreign. That's why you get problems like allergies and organ rejection. If an alien organism is enough like us to pose an infection risk, then it's also most likely similar enough to trigger an immune response. And the diseases that we face today have had millions of years of evolution to prepare them for our immune system, whereas anything alien has not. So even if life elsewhere is very much like life here, it'll have the same catching up to do that we will. Admittedly pathogens evolve faster than their hosts, but then again these hosts have medical technology to make up the difference.

Re:Space/Genetic Exploration

[Anonymous Coward]

IAAMB (I am a Microbiologist), and I've heard this argument a million times from a million people that don't really understand the concept of pathogens. A few points worth mentioning:
1. Highly infectious diseases behave that way because they jump from a species in which it has coevolved (HCV in humans, Influenza in birds, various other diseases in pigs, rats, insects, etc), and so become not-terribly-pathogenic and suddenly entered a situation where it can jump species to another host. The extreme death rate of these diseases is a direct consequence of the fact that they DIDN'T evolve in the presence of humans, and that the new host behaves in an entirely unfamiliar manner to the foreign viral strain. Killing every organism it comes across is a horrible way for a virus to survive - the ideal is to achieve a minimal killing rate such that it becomes endemic to the population, with only a small proportion falling ill and dying. As such, our hypothetical alien virus has the potential to behave in this manner, provided the alien host is biochemically similar to us in one or more of the modes of entry for the viral strain. Admittedly, this only gives the potential for a mutant strain that could mess you up, but it's the same idea as Influenza - most truly common strains can't hurt you, but repeated contact with it in close quarters can give rise to an infectious system. Now, the true argument here is that it's unlikely that these hypothetical alien species we run into will have similar cell-surface proteins or modes of entry into the body - but simply arguing that a virus cannot infect a species it's never seen is a naive and deceptive idea. The far greater danger is...
2. Infectious microbes. The alien equivalent of bacteria, fungus, protozoa, worms, etc. It is quite likely that we will encounter a species which benefits from growing in a human-like environment, most likely some kind of warm, damp tissue bed. Find a rapidly growing strain of alien microbe which digests its food externally, mix well with a human mucus lining, and you very rapidly have the potential for a flesh eating species. Equally likely is that one of the common hormones fed out into the air by alien critters (think of the compounds produced by plants et al for communication) behaves as a carcinogen to the naive human metabolism, or acts as some kind of hormone mimic. Industry produces such compounds all the time, not to mention legitimate toxins on Earth - there's no way of saying that the air on a warm spring's day on an alien world wouldn't be lethal to us due to immediate and violent immune responses to the foreign contaminants. There are many possibilities about what alien organisms might do to us, and it's silly to think that just because we've never seen it, it won't cause some kind of mass physiological response.

Needless hype: good publicity or bad conditioning?

[dtolman]

hey kids! Exciting news a planet could have life - assuming it has an atmosphere. And if it does have that atmosphere, it doesn't overheat the planet through greenhouse heating. And oh yeah, all we know about it is its orbit and mass. And it almost definitely doesn't have life. Aren't you excited?

When the media flogs "science" stories like this, full of marginal ideas that probably aren't true are we just conditioning the public to ignore actual science as pie in the sky crap? Or does the break from Paris Hilton news stories have some tangible benefit to educating society at large?

Might be hell to live on...

[jhsiao]

The planet is so close to the star that it's likely tidally locked so that only one side faces the sun and the other side is in eternal night. The temperature differential between the hot day side and the cold night side might cause the border to be under constant storm activity.

A "year" where the planet rotates around the star is only 13 days. If tidally locked, a "day" is the same amount of time.

The same tidal forces would also make any large oceans on the surface prone to immense tides. The strong tides may also result in more tectonic activity than on Earth.

Re:Might be hell to live on...

[dottyslashdottydot]

No, if it's tidally locked, there will be no "immense tides" in the oceans. Tidally locked means the same face of the planet is always facing the star. Just like the same face of the moon faces the earth... the moon is tidally locked to the earth. On this planet, any oceans would be higher at the points closest and furthest away from the star, but unlike the earth, these 'bulges' would never move, and water levels wouldn't change much, therefore no tides, at least from the star alone. The other planets in the system would most likely have some sort of influence on that planet's oceans.

Complete and Utter Failure

[Rauser]

"We twice aimed large antennas in the direction of Gliese 581, hoping to pick up a signal that would bespeak technology"

The first interspace wardriving attempt thus ended in failure. The Gliesians must be hardwired.

Re:Needless hype: good publicity or bad conditioni

[frogstar_robot]

A planet of Earthlike mass in the habitable band would almost certainly have to have an atmosphere of some kind. Whether or not that atmosphere is breathable or not is another question altogether. From that distance, Venus or Mars would look pretty good to extraterrestial terran planet hunters. Masswise Venus is a near twin of earth but the surface conditions are straight out of Dante's Inferno. Mars is a shade too light to hold on to a thick O2 atmosphere and is basically a cold rusty desert. My guess is this place is apt to be more like Venus or Mars than Earth. Any chance we could talk Goldilocks into planet hunting?

Re:Quick...

[PixelScuba]

And now... Deep Thoughts ...by Jack Handey.

"I can picture in my mind a world without war, a world without hate. And I can picture us attacking that world, because they'd never expect it."

uh-oh

[jollyreaper]

God help those poor bastards if they've got oil.

Let's be real...

[__aaclcg7560]

Gliese 581 is, as astronomical distances go, relatively close: only 20 light-years away. It's one of the few star systems which, if inhabited, might provoke conversation. A simple exchange, along the lines of "how are you?" followed by "fine, and you?" would require a mere four decades. Tedious, but not unthinkable.

The actual exchange...

EARTH: How are you?

GLIESE 581: Sorry, we don't need Viagra. You can try the next planet over.

Re:kill the aliens

[Ihlosi]

kill the little green men, wipe them out, colonize.

Well, I'm pretty sure the little green men will do one of the following:

a) Disable our colony ships main computer with a computer virus written quickly by one of their hacker geniuses and then hit it with a nuclear warhead while our colonists are waiting for Windows to boot up again.

b) Find out that a very common, harmless (to them) substance on their planet is highly toxic to us humans and douse any unwelcome visitor with it.

c) Realize that their equivalent of the common cold is a deadly plague for humans.

d) Send in the little green men in black to take care of the human invasion, then mind-wipe any innocent bystanders.

e) Travel back in time and keep Earth from forming.

Anthropomorphize much?

[zoips]

It'd be cool if someone would come up with a more interesting argument than we're perfect, everything here is perfect, so it's the only way to go. It's a good logical starting point, go with what you know, but claiming that life on Earth is the only way to go because that's how it works here is, well, basically begging the question, and last I heard, logical fallacies are bad.