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New Paper Offers Additional Reasoning for Fermi's Paradox
Posted by
ScuttleMonkey
on Mon Feb 02, 2009 03:01 PM
from the better-odds-if-we-would-just-start-colonizing dept.
from the better-odds-if-we-would-just-start-colonizing dept.
KentuckyFC writes "If the universe is teeming with advanced civilizations capable of communicating over interstellar distances, then surely we ought to have seen them by now. That's the gist of a paradoxical line of reasoning put forward by the physicist Enrico Fermi in 1950. The so-called Fermi Paradox has haunted SETI researchers ever since. Not least because if the number of intelligent civilizations capable of communication in our galaxy is greater than 1, then we should eventually hear from them. Now one astrophysicist says this thinking fails to take into account the limit to how far a signal from ET can travel before it becomes too faint to hear. Factor that in and everything changes. Assuming the average communicating civilization has a lifetime of 1,000 years, ten times longer than Earth has been broadcasting, and has a signal horizon of 1,000 light-years, you need a minimum of over 300 communicating civilizations in the Milky Way to ensure that you'll see one of them. Any less than that and the chances are that they'll live out their days entirely ignorant of each other's existence. Paradox solved, right?"
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Number of ET Civilizations In Our Galaxy Is 37,964 544 comments
KentuckyFC writes "The famous Drake equation calculates the number of advanced civilizations in our galaxy right now. But the result is hugely sensitive to the assumptions you make about factors such as the number of habitable planets that orbit a host star, how many of these actually develop life and what fraction of these go on to become intelligent etc. Disagreements about these figures leads to estimates for the number of advanced civilizations ranging from 10^-5 to 10^6. Now an astronomer in Scotland has worked out how to make the calculations more precise so that different theories about the origin of planets, life and civilizations can be compared. His calculations say that the rare-life hypothesis predicts only 361 advanced civilizations in the Milky Way now. However, the so-called tortoise and hare hypothesis predicts 31,573 and the theory of panspermia says that there ought to be 37,964 extraterrestrial civilizations more advanced than our own in the Milky Way."
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Milky Way Heavier Than Thought, and Spinning Faster 285 comments
An anonymous reader writes "The Milky Way is spinning much faster and has 50 per cent more mass than previously believed. This means the Milky Way is equivalent in size to our neighbor Andromeda — instead of being the little sister in the local galaxy group, as had been believed. One implication of this new finding is that we may collide with Andromeda sooner than we had thought, in 2 or 3 billion years instead of 5."
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Rydberg Molecule Created For the First Time 127 comments
krou writes "The BBC is reporting that the Rydberg molecule has been formed from two atoms of rubidium. Proven in theory, this is the first time it's been created, reinforcing the fundamental quantum theories of Enrico Fermi. Chris Greene, the theoretical physicist who first predicted that the Rydberg molecules could exist, said: 'The Rydberg electron resembles a sheepdog that keeps its flock together by roaming speedily to the outermost periphery of the flock, and nudging back towards the centre any member that might begin to drift away.' It's a sheepdog with a very short life-span, however; the longest lived molecule only lasted 18 microseconds. Vera Bendkowsky, who led the research, explained how they created the molecule: 'The nuclei of the atoms have to be at the correct distance from each other for the electron fields to find each other and interact. We use an ultracold cloud of rubidium — as you cool it, the atoms in the gas move closer together. We excite the atoms to the Rydberg stage with a laser. If we have a gas at the critical density, with two atoms at the correct distance that are able to form the molecule, and we excite one to the Rydberg state, then we can form a molecule.'"
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And I thought... (Score:5, Funny)
I thought it was because as they reach our level of civilisation, they built giant particle accelerators for research and turned their planets into black holes.
The First Ones (Score:5, Insightful)
Re:The First Ones (Score:5, Funny)
FIRST POST!
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Re:The First Ones (Score:5, Insightful)
Maybe a zillion races have achieved the capability at roughly the same time, and are just more than 100 light years away from us.
What are the odds of anyone picking up our broadcast noise anyhow? It's not like we're aiming high wattage transmissions directly at likely stars, and with the transition to digital, our signal becomes even more ellusive (smaller spectrum footprint).
It's just as likely that other races only went through a brief period of wideband, and then switched to wired or line of sight optical or quantum bits or some crap we haven't even thought of yet.
The whole paradox is the height of hubris: aliens have to be like us, they have to advance along the same technological track, and they have to be broadcasting on a scale that we can easily pick up...We haven't cataloged every star yet, and that's an order of magnitude over any artificial broadcast we can understand.
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But if that's right... (Score:5, Insightful)
God I hate Fermi's Paradox. (Score:5, Insightful)
This is hardly a new idea. It's so not new that I think I remember saying something similar about two years ago [slashdot.org], and I'm not exactly an expert.
Analog signals degrade quickly, and digital signals are worse, in their way, because they don't tolerate degrading as well. Couple that with broadcast limitations imposed by local governments to keep signal strength down, and I can't see how our signal could be reliably detected more than a few light years away without a HUGE radio antenna array.
only humans think in this way (Score:5, Funny)
We humans are still a bunch of young, angsty teenagers. We desperately want to make the "first contact", crying and yelling and suffering from the depressive thought of loneliness.
Other galactic civilizations simply matured and stopped worrying about such pointless things. They make themselves busy with real business.
Grow up, humans.
Lots of other reasons, too... (Score:5, Insightful)
Unless it's been vastly misrepresented in mainstream presentation (like TFS), Fermi's Paradox sounds pretty ridiculously simplistic.
Other bad assumptions it makes, just off the top of my head:
1. Other intelligent civilizations want to engage communications with aliens who, for all they know, might try to blow them up or eat them.
2. Those civilizations are willing to spend resources to beam electromagnetic radiation out into space in the vague hope of someone noticing.
3. Other intelligent civilizations "capable" of "communication" will follow the same technological arc as us and develop electromagnetic communications rather than, say, quantum communications or something we haven't even thought of yet.
4. Those aliens will assume that WE (or some unknown aliens) will be listening carefully for extrasolar broadcasts.
5. Those aliens even have a concept of "communication" and aren't just some hive-mind that never needed to evolve social skills.
6. They didn't cut their Alien-SETI funding to pay for medical research or an Alien-Wall-Street bailout package or something. (I mean, what do you think the chances are that WE will broadcast for a thousand years?)
And so on.
Really, Fermi's Paradox sounds like me saying that if I sit on a lonely beach for a week and don't find a bottle with a message in it in proper English, there are no other intelligent beings in the world.
Middle of nowhere (Score:5, Funny)
It's not like we're located close to Downtown Galaxy. We live out on the edge. There's probably some galactic equivalent of AT&T or Comcast that is telling everyone else "We'll be providing them with service 'soon'. So our monopoly is justified."
Either that or the installer showed up and we were too busy/unaware to answer the door. So they said they'd be back later.
Re:It's quite clear what the reason is (Score:5, Funny)
...the universe was created 6k years ago.
Hey - There's no room for rounding if you're going scriptural on us. The Earth's creation started the night before Oct 23, 4004 BC. [wikipedia.org] (In case anyone was wondering, Earth is a Libra.)
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Re:It's quite clear what the reason is (Score:5, Funny)
Is that Julian or Gregorian?
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Re:It's quite clear what the reason is (Score:5, Funny)
That explains the drama-queen mood and temperature swings, then.
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Re:It's quite clear what the reason is (Score:5, Interesting)
Actually, IIRC, the Pope made a declaration a while back that there's nothing biblical that bars the existence of extraterrestrial life. For many people who are strongly devoted to one religion or another, even finding a note from their messiah announcing "Just kidding - I didn't think that y'all were going to take me so seriously. Hopefully after I die, somebody will find this and avoid any real disaster," would defer them from their beliefs.
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Re:It's quite clear what the reason is (Score:5, Funny)
I, for one, found his ideas intriguing and wish to subscribe to his newsletter.
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Re:Solved? (Score:5, Interesting)
And if they're communicating by some mechanism that we can't read? E.g. the equivalent of "subspace radio".
Or maybe it's a point to point via laser (see Niven's Known Universe).
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Re:Solved? (Score:5, Funny)
Exactly. Maybe all those "crazy" people are actually talking to aliens.
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Re:Solved? (Score:5, Funny)
No - Those people really are crazy.
The aliens talk only to me and I have the good sense not to answer them (at least not out loud). I just carefully carry out their instructions and try to get mixed up with those crazies.
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Re:Solved? (Score:5, Interesting)
True. The calculation of 1000 years seems a bit too long. We can't figure out how to shorten it because we don't know how long we're going to be using broadcast signal based communication as opposed to some other more direct means.
Besides . . . attempting to extrapolate with so many unknowns is, at best, an exercise in postulation. At worst, it is dangerously misinforming.
Parent
Re:Solved? (Score:5, Funny)
Right now our civilization is like a closed source application running on a dev box off the network. If the hard drive dies, the code is toast. But as soon as you get that code in Git, its a whole lot harder to kill.
Ok, so that was a terrible analogy.
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Re:Solved? (Score:5, Funny)
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Re:Solved? (Score:5, Interesting)
Maybe there really is no FTL, and other alien races are as leery of sending out giant seedships that they themselves can't ride in as we are, and are thus still hanging out in their home starsystem.
Maybe aliens are everywhere, aware of us, and simply choosing not to communicate.
Disproving aliens deductively is the opposite of science. The lack of easily obtained evidence for alien life is far from damning given the area that we are capable of observing with any real scrutiny.
Parent
Re:Solved? (Score:5, Insightful)
"Paradox solved, right?"
No. Some planets suitable for life have almost certainly existed in this galaxy for billions of years longer than the Earth. By now, one would expect there to have been civilisations that spread throughout the galaxy and therefore brought Earth within detection range of their signals...
But they would have to be within earth's range in the last 100 years or so for them to detect us. "Billions of years" means they could have existed on Venus before humanity ever showed up, for all we know. If they were that close, the signals would have long since passed us by at the point we were discovering fire.
Or they could have been reasonably nearby, but too far for the signal to reach us without fading out completely.
Or they could be using a different form of communication than we are able to perceive.
So, honestly, "expecting" anything is a little silly and assumes far too much.
Parent
Re:Solved? (Score:5, Interesting)
Assuming you can't skirt around the light barrier then that basically means sending small groups of people (or aliens or whatever) across trillions of miles, probably in some kind of hibernated state, in the hope that they'll bump into a habitable somewhere, set up shop, and begin to populate. Any returns on investment will be very intangible indeed- physical goods have to come back the same way they came (meaning it would have to be extraordinarily valuable to merit the shipping and handling on an interstellar ark) and information is cheap. You'd need to expect a very valuable treasure-trove of knowledge indeed for information to start making sense as an expected ROI.
I know many people just assume that interstellar travel is the "next step" in the development of societies but the longer I look at it the less it seems to offer tangible benefits for the people who have to invest in this.
I expect a society thinking in the long-term would obviously see the benefits of spreading one's seed across multiple star systems... but you have to postulate the existence of a society that takes the long view. Considering how easily a society as advanced as ours (not saying we're very advanced: just a society at the same level of advancement as us) is busily undermining its own biome, knows it's doing it, and doesn't care, and took pains to smother other societies which might have taken the longer view, I don't think we should expect many societies to reach the "long-view" stage before they wiped themselves out or got wiped out.
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Re:300 isnt teeming with life (Score:5, Informative)
Parent
Re:What paper? (Score:5, Funny)
I don't know about you, but I prefer a link to a blog over the actual paper. Mostly because I don't speak Astrophysicsese.
I went ahead and clicked on the blog for you, and the link. Here's the paper (You can get a PDF if you want), it was submitted to the International Journal of Astrobiology.
http://arxiv.org/abs/0901.3863 [arxiv.org]
I understand your reluctance, after all you're the one who posted:
http://slashdot.org/comments.pl?sid=1112493&cid=26694469 [slashdot.org]
Don't worry, you can continue to click on links out of curiosity. I put one above, go ahead, click it. You know you want to. everyone else is clicking it. Now with more fiber, and it cures Alzheimer's too.
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