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This is either the worst or the best news I have ever heard
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.
Here is the story. That planet is only about twenty light years away. Are earth-like planets so common? That probably means lots more civilization-supporting planets than I had expected. But where are the alien visitors? As suggested by the Fermi paradox, we must revise our priors along several margins, one of which is the expected duration of an intelligent civilization.
We already have a civilization, so the added optimism on that front doesn't help us much. On the other hand, we don't know how long our civilization will last, but now we must be more pessimistic.
I might be happier if I were more altruistic toward possible alien races; right now my appreciation for them is mostly aesthetic (modally speaking, that is), not empathetic. All you alien altruists should be jumping for joy. Holders of selfish, planet-based moralities should despair.
No matter what the proper galactic welfare function, I suppose I should be wracked with emotion. I'm not.
Posted by Tyler Cowen on April 26, 2007 at 07:04 AM in Science | Permalink
Comments
This discovery is indeed very interesting.
What's more interesting is that the mass of this planet is 5 times bigger than Earth's.
If there is intelligent life on that planet, they probably would not find us so easily, since our mass is five times smaller than theirs. The various other characteristics of their planet would probably be quite different from ours as well, and they are probably looking somewherelse for planets that are more similar to theirs than to ours.
Posted by: Fabio at Apr 26, 2007 8:08:06 AM
There is a second solution to the Fermi paradox; sufficiently advanced civilizations stop exploring and communicating, instead choosing to turn their energies inward. Ours seems fond of video games. Geoffrey Miller's idea in a nutshell.
Posted by: lw at Apr 26, 2007 8:24:08 AM
One 'optimistic' resolution to the Fermi Paradox might be that, for whatever reason, more advanced civilizations pretty quickly stop using the EM spectrum the way we do. Though even then, for as often as the Fermi Paradox is invoked, I've never really heard anyone explain over what range we should be able to detect other civilizations that have a similar EM output to our own. That's probably a relatively simple inverse-square law calculation, but even that I'd take it with a grain of salt as our understanding of the structure of space-time outside of our own solar system isn't as great you might think (see dark matter and dark energy) or even within it (assuming there's still no adequate 'technical' explanation for the pioneer anomaly ).
This particular discovery doesn't really affect to the calculations too much, I don't think. It seems like they're always detecting smaller and smaller extrasolar planets pretty much as soon as the hardware and methodology are up to it, and nothing about 581 C really comes as a surprise. Unfortunately, beyond refining its mass/orbit a bit, it'll probably be a while before we can actually tell much else.
Posted by: mtc at Apr 26, 2007 8:48:45 AM
"We already have a civilization..."?
Are you sure?
More seriously, who's the "we"--all human beings or some subset? I'd read you as saying "residents of earth". It seems to me a truism that the best way to minimize differences is to switch the basis of comparison. Once we start thinking about civilization on another planet, all the global war on terror stuff fades. Of course, who's to say that another planet has just "one" civilization.
Posted by: Bill Harshaw at Apr 26, 2007 9:23:10 AM
If there is intelligent life on that planet, they probably would not find us so easily, since our mass is five times smaller than theirs.
I think we could find a sufficiently intelligent civilization of cat-sized creatures.
- Josh
Posted by: Wild Pegasus at Apr 26, 2007 9:35:34 AM
My casual impression is that we don't need a particularly exotic explanation for the Fermi paradox even if vaguely-Earth-like planets are scattered every 20 light years or so. I look at the history of Earth, with severe events like dinosaur-killer asteroids and milder events like climate fluctuations, and I find it easy to believe that we are arbitrarily far out on the lucky tail of a galactic distribution of planet-killing events averaging every 25 million years or so. I don't think that the Earth's history *proves* that explanation or anything, just that it raises it as an obvious possibility, and with that possibility in mind, more exotic explanations seem unnecessary. (Though exotic explanations may still be fun, e.g., thinking about how civilizations which learn enough physics inevitably exterminate themselves by doing an innocent-looking experiment which turns out to collapse their solar system into a black hole.:-)
Posted by: William Newman at Apr 26, 2007 9:47:21 AM
Josh, I believe Fabio was referring to the mass of our planet, not the mass of the average human. So it would be harder for extraterrestrials to find an Earth-sized planet, than it was for us to find this 5x Earth-sized one. I don't know how much more difficult, though.
P.S. The images evoked by your phrase "a sufficiently intelligent civilization of cat-like creatures" had me in stitches...
Posted by: Vasu at Apr 26, 2007 10:08:30 AM
We're not alone! Isn't that enough for now? Why the downer?
Posted by: ricpic at Apr 26, 2007 10:22:23 AM
Fabio: A decade ago we could only find super-Jovian planets. Now we're at 5X earth's mass (and 2X earth gravity, so the residents could be Flores sized, not just cat-sized, giving them reasonable cranial capacity).
Tyler: Surely learning about the Doomsday Paradox was worse, no?
Even that pales compared to coming to an appreciation of how tiny the region of optimization-space inhabited by Friendly AI or other forms of human-meaningful optimization process is, relative to the whole of optimization space.
Of course, for those who have been theists there are probably larger disappointments still, at least in theory, but there are very few theists in the relevant sense.
Posted by: michael vassar at Apr 26, 2007 11:07:47 AM
Surely this raises the odds that some of those who claim to have seen UFO's have actually seen something from beyond our planet.
Posted by: happyjuggler0 at Apr 26, 2007 11:58:49 AM
Well, it's still a ridiculously long-shot. I still have some doubts about the science of determining the presence of planets by measuring the wobble in a star - I'm sure people have thought about it a lot, but there are just so main the 20 light years of space between us and Earth 2.0 (said sarcastically) that can gunk up our data.
And even saying that the planet *is* there, we don't know anything about the atmosphere, which might be ridiculously thick, making the planet too hot to support life. And even if the atmosphere is balmy, the planet might not be geologically stable. Or it might be bombarded with comets. Or just about anything.
I don't know that there's intelligent life out there, but I'm pretty sarn sure that if there is, we are currently incapable of finding it.
Posted by: amissio at Apr 26, 2007 12:00:34 PM
"Earth-like planet" is a misnomer. If they said "Mars-like planet", "Venus-like planet" or "Mercury-like planet" it would be equally accurate. Simply having a planet our size is not sufficient. All this proves is that instead of a 1 in 4 chance, it's not a 1 in 5 chance. Those odds will get worse.
Nor should we overestimate the possibility for intelligent life. It's occured once in many millions of years in Earth's history. Not good odds either.
Nor can we state with certainty that any intelligent species will develop a technological civilization. If they don't have opposable thumbs - too bad for them, no matter how brilliant they are. Won't do them any good if they can't use or create tools.
If Jared Diamond is correct in Gun, Germs, and Steel we see that there are many things required for civilization to progress. We can't assume that geography, mineral resources, and distribution of flora and fauna will give any intelligent species the tools needed to build civilization.
More information on astronomy is always good, but to speculate this increases the chance of finding life is premature.
Posted by: Chris Du at Apr 26, 2007 12:40:59 PM
Well, the mystery is the SETI data, or lack thereof. It is now getting close to four decades, or maybe
even a bit longer, that we have been consciously beaming out all kinds of radio emissions aimed specifically
at communicating in a hopefully friendly way with alien "civilizations" close enough to our level that they
would bother with the EM spectrum. So far, no clear replies, and the net has now gone pretty far and
wide.
Besides the "there ain't nobody out there worth talking to" (quite possible) to the "they are not listening
to the EM spectrum because they are so super advanced" possibility is another one, more along the latter
line. This would be one that indeed there is a whole alien empire/civilization/superstructure that is out
there and watching us. It may have well-established bureaucratic way of dealing with emerging planetary
civilizations that involves keeping an eye on them and waiting for them to reach some appropriate level
before they are openly communicated with and invited to join the system.
The "evidence" for this is peculiar and not too reliable. It would be the fact that we had this huge
outbreak of UFO sightings in the late 1940s. Of course it is quite likely, probably very likely, that
these were all just a mass hysteria of the time, that there were not then and are not now any UFOs, or
at least any that were/are actual alien vehicles. But, suppose that outbreak reflected an actual
empirical reality, that we had a wave of alien visitors in the late 1940s? Well, this would be
consistent with an ordered bureaucratic galactic or whatever civilization keeping tabs. After all,
I would bet that if such a system existed, the achievement of nuclear power would be one of those
leaps that would trigger a closer watch. "Oh, those earthlings, now they have nukes; we had better
start keeping a closer eye on them, see if they can behave peacefully and responsibly or if they
will just go and blow themselves up." I would remind that 1945 was the year we reached that stage,
so a wave of such visitations for such observational purposes would be perfectly consistent.
Posted by: Barkley Rosser at Apr 26, 2007 2:33:19 PM
I'm surprised no one has mentioned this theory yet.
They're out there, they're plentiful, and they want to avoid us.
Posted by: John Aspinall at Apr 26, 2007 3:16:04 PM
"Only" twenty light years away?
Pshhht. This is irrelevant to us Earthlings.
Posted by: CL at Apr 26, 2007 3:25:53 PM
I think we are all jumping to conclusions. All we know is that there is a planet of 5 Earth masses in the goldilock's zone around this star. We also know that this star has about half the metallicity as does our sun.
This planet could be anything. It could be a Venus-like hell-hole. It could be a water world, with oceans hundreds of kilometers deep. It is actually not likely to be a Mars-like planet, because the gravity would have held on to the atmosphere over the eons. We won't know what kind of planet it is for a long time to come, because our telescopes simply do not have the resolution to do the spectro-analysis to determine these things.
Untill we know these things, we cannot say that the Rare Earth Hypothesis (REH) has been disproven. There is one theory about star systems that has been disproven. This star system has only half the metallicity as does our own. This means that terrestrial planets (and smaller gas giants) do indeed exists in systems of relatively low metallicity. This increases the number of stars likely to have planets by about a factor of 5 over that predicted by the REH. No other aspect of the REH has been disproven at this time.
Does this planet have plate tectonics? This is believed to be essential for the formation of multi-cellular life by the REH. The current theory is that a large moon is necessary for the initiation and the continuation of plate tectonics. Venus has no plate tectonics.
My pet theory is that, without plate tectonics, you get a venus. My thinking is that plate tectonics allows for vulcanism and what not that allows for all of the heat and gas to leak out of the planet in a controlled fashion. If there are no plate tectonics, all of this energy remains trapped in the planet and builds up, until you get a global "resurfacing" event. This is an idea I pulled out of my arse a few months back and I have no idea how valid it is. If its valid, most "earth-like" planets will turn out to be Venus-like hell-holes.
Even if these does turn out to be a habitable planet, this still does not mean that intelligence is likely. Single-celled organisms have been around since the beginning of the Earth. Multi-cellular life has been around for only around 750 million years. This alone suggests that the majority of habitable planets will have blue-green algae and nothing else. There are a considerable number of evolutionary steps to go from blue-green algae up to us. Even if there are a billion habitable planets in the galaxy (the highest plausible estimate), it could still be the case that we are alone.
I still think we are alone and that we have nothing to worry about.
Posted by: Kurt9 at Apr 26, 2007 4:14:25 PM
It is now getting close to four decades, or maybe even a bit longer, that we have been consciously beaming out all kinds of radio emissions aimed specifically at communicating in a hopefully friendly way with alien "civilizations" close enough to our level that they would bother with the EM spectrum. So far, no clear replies, and the net has now gone pretty far and wide.
Even as very much of a SETI skeptic myself (though a hopeful!), this statement is completely false and misunderstands the SETI effort. SETI is concerned with detecting signals sent from another civilization - not sending out signals and waiting for a reply. At most, only ceremonial signals have been sent (one was aimed at a galaxy 25,000 light-years away so I can assure you nobody is waiting for a reply) to announce to someone that we are (or were) here, but they have nothing to do with SETI. Nobody is seriously "beaming . . . radio emissions aimed specifically at communicating" with another civilization.
Also, to say the net has gone far and wide would be nonsense even if there was a "net" being cast. If we were sending out signals and waiting for a reply (which we're not) the greatest distance they could have traveled and generated a reply which we would have received in 40 years is, quite obviously, 20 light-years which is hardly "far and wide" on a cosmic scale.
SETI is simply about finding evidence of another civilization. Not even the biggest SETI advocates believe there is any reasonable chance of actually communicating (i.e. two-way communication) with another civilization in any one person's lifetime. Distances are simply too great for that. That is why nobody wastes time sending out signals. It is also why I'm a SETI skeptic - the cosmic time and space scale is so vast beyond our traditional comprehension that the odds of picking up a signal seem to me to be extremely small at best. I would certainly love to be wrong about that, but I don't expect to be.
Posted by: Brian Courts at Apr 26, 2007 4:46:51 PM
Brian,
You are correct; I was wrong. The "net" reference came from a Scientific American article of a few years ago
on this. It is a function of how strong the signal would be vesus distance to be heard. So far, we have not
picked anything up.
Posted by: Barkley Rosser at Apr 26, 2007 6:28:26 PM
C.S. Lewis' view seems to be that we are the only fallen planet and the other races stay away from us because we are monstrous. I always liked that idea.
Another suggestion I read about in John C. Wright's The Golden Age is that if you extrapolate the trend of shrinking electronics far enough into the future, that there may be microscopic supercomputers floating around the earth right now that we cannot detect. They may be imminently close and we'd never know ... also cool.
Posted by: Kevin at Apr 26, 2007 7:02:27 PM
I think the evidence is piling up that we humans are not going to last a whole lot longer...
Posted by: Paul N at Apr 26, 2007 10:08:50 PM
I agree with George Carlin. We are the trailer trash of the universe. If there is intelligent life, why would they want anything to do with us.
Posted by: ADAM M at Apr 26, 2007 11:13:32 PM
Well, until someone explains how life first developed on this planet, then any estimate about how frequently it can develop anywhere is going to be nothing more than a wild-assed guess. For all we know, life of any type only develops once in a trillion galaxies, and I haven't even addressed the fact that only one species has ever developed electro-magnetic communication on this planet in the entire time life has existed here.
Occam's razor suggests to me that the answer to the paradox is that we are actually alone in this universe.
Posted by: Yancey Ward at Apr 27, 2007 1:02:14 PM
Two academics and government consultants have written a book discussing the possibility of a hostile alien visitation. They revisit Fermi's Paradox and rename it "Fermi's Blunder", concluding that the possibility of alien contact is sufficiently non-zero that we should seriously think about how to respond to any extraterrestrial threat. I wrote about the book in a feature for Reuters.
Posted by: Scott Hillis at Apr 27, 2007 1:18:07 PM
'just 20.5 light-years away in the constellation Libra.'
and nobody has made a Battlestar Galactica reference yet?
Posted by: dexev at Apr 27, 2007 2:55:40 PM
This is great news. Now we have a planet 5 times the size of our own to rape of it's resources. Maybe this'll lower gas prices.
Posted by: Tim at Apr 29, 2007 11:56:45 PM
