Number of ET Civilizations In Our Galaxy Is 37,964 544
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."
yuck. (Score:4, Funny)
yuck.
Re:yuck. (Score:5, Funny)
Like I said before, it adds flavor to a rather dull blend.
Aliens Cause Global Warming (Score:5, Insightful)
http://www.crichton-official.com/speech-alienscauseglobalwarming.html [crichton-official.com]
My personal guess is that there are OVER 9000 civilisations out there.
Re:Aliens Cause Global Warming (Score:5, Funny)
Re:Aliens Cause Global Warming (Score:4, Funny)
Yeah, thats why we have this crazy velociraptor problem here in L.A.
Re:Aliens Cause Global Warming (Score:5, Funny)
I don't mind the normal velociraptors, but I do try to avoid the crazy ones.
Re:Aliens Cause Global Warming (Score:5, Interesting)
His criticism of SERI is basically saying "the hypothesis that the neutrino has a rest mass of zero is scientific, but the hypothesis that a neutrino has a rest mass that is not zero is unscientific." This is silly; the same experiments would be used to test either hypothesis. Likewise, it's silly to criticise SETI by saying it's scientific to listen for radio signals if you're trying to show that there aren't any, but it's not scientific to listen for radio signals if you're trying to see if there are any. It's the same experiment either way.
His criticism of the Drake equation is even less well informed, in that he's criticising the equation itself, not the parameters that go into it. But the equation is trivially true; it's nearly a tautology. If the correct statement is "we don't know", it's not because the equations wrong, it's because we don't know what values go on the right side. But the answer "we don't know how many civilizations are in the univererse because we don't know what the probability is that a planet with life develops a lifeform with intelligence still bounds the question-- it tells us more precisely what we don't know.
In short, Crichton should stick with novels, which he's good at, and not critiquing SETI, something he seems to know little about.
Re:Aliens Cause Global Warming (Score:5, Insightful)
His criticism of the Drake equation is even less well informed, in that he's criticising the equation itself, not the parameters that go into it. But the equation is trivially true; it's nearly a tautology. If the correct statement is "we don't know", it's not because the equations wrong, it's because we don't know what values go on the right side.
From Crichton's piece:
"The problem, of course, is that none of the terms can be known, and most cannot even be estimated. The only way to work the equation is to fill in with guesses."
He IS talking about the parameters (on the right side). Your criticism is meaningless.
In short, Crichton should stick with novels, which he's good at, and not critiquing SETI, something he seems to know little about.
Hehehe. Marvelous. Keep it up.
Re:Aliens Cause Global Warming (Score:5, Insightful)
"The problem, of course, is that none of the terms can be known, and most cannot even be estimated. The only way to work the equation is to fill in with guesses."
He IS talking about the parameters (on the right side). Your criticism is meaningless.
No, he also says "Speaking precisely, the Drake equation is literally meaningless, and has nothing to do with science." and that I disagree with. Let's say you want to find the population development, and find the formula: population[n+1] = population[n]*(1+birth rate-death rate)+immigration-emigration. Then we investigate these factors and realize that we don't have enough data to tell us anything useful. Is it then unscientific because we never actually got an answer? No, we took a complex question and decomposed it into simpler questions that can be investigated individually in a very scientific way. We are probably a lot more certain we can't answer the question than before. That kind of meta-knowledge is very important and useful as building blocks to make new experiments to find out. Of course, wild ass guesses and saying there's 37,964 ET civs is unscientific, but he's throwing the baby out with the bathwater.
Re:Aliens Cause Global Warming (Score:5, Interesting)
Not quite. It implicitly presupposes a steady-state universe, which was commonly believed at the time. However, we now know that the universe is not steady-state, and in fact is quite young (13.7 Gy) compared to the age of the Earth (4.55 Gy). Especially if the conditions in the Universe have been shifting, e.g. it has taken time for stars to build up enough metallicity, it is entirely plausible that conditions may be hospitable to life, and yet it is not common, simply because we just got there first. This is particularly important if you accept the conclusions of the Fermi Paradox, which basically states that since technological advancement is so rapid compared to evolution, the first technological civilization in a galaxy will almost inevitably colonize the galaxy before any other civilization has had time to evolve.
What a great example! (Score:5, Insightful)
Re:What a great example! (Score:5, Funny)
The original estimate was 32768 and an overflow flag.
Re:What a great example! (Score:5, Informative)
That's 32767 and an overflow flag.
And get off my lawn.
Re: (Score:3, Funny)
Give him a break, he's still working on an old Pentium system.
Re:What a great example! (Score:5, Insightful)
Here is an interesting one. (Score:5, Interesting)
No kidding. Our current estimates of the number of stars in the galaxy only go to about one significant figure, with upper and lower estimates differing by a factor of two. That puts a pretty serious cap on the precision of his answer.
One of my peers is an astrophysicist. Nearly all of their calculations are done to ONE significant figure. It ends up that they typically just add up exponents. The numbers are usually so huge, eg. 1E27, that they can get away with this.
:)
When you are dealing with orders of magnitude like these, it is usually acceptable in the scientific community. Whether this de-facto standard *should* be so acceptable is still up in the air in my views
Re:Here is an interesting one. (Score:5, Funny)
That's probably because they assume too many spherical cows.
Re:Here is an interesting one. (Score:4, Funny)
But wait...if the cows are spherical then how do we know they are always facing north?
Re:Here is an interesting one. (Score:4, Funny)
Ah yes, the classic mistake ... cowrelation does not imply cowsation.
Re: (Score:3, Funny)
Reminds me of an astrophysics joke:
Q: How many astrophysicists does it take to change a lightbulb?
A: 2 ± 53
Re:What a great example! (Score:5, Insightful)
This is the problem with the Drake equation
Most of the factors are not known to any great precision
Most of the last factors are not known at all ...since we only have one example, us.
With it you can prove that there are a vast number of civilisations or none just as easily
There are currently 53.4565452112323(56) civilisations in our galaxy ....
Re:What a great example! (Score:5, Funny)
It must be right, because the answer came from a computer.
Re: (Score:3, Funny)
Re: (Score:3, Insightful)
Re: (Score:3, Funny)
and why did I read that as early penguins?
Anyhow: I for one welcome our new extraterrestial penguin overlords!
Re:What a great example! (Score:5, Funny)
But the question didn't. We should make a bigger computer to determine what the question should have been.
Re: (Score:3, Funny)
Done!
Answer just in:
Hmm... I always thought something was fundamentally wrong with the universe...
Re:What a great example! (Score:5, Insightful)
Re:What a great example! (Score:5, Funny)
Re: (Score:3, Funny)
Congratulations, you now hold the unbeatable record for "Shortest +5 Funny Comment Ever". Comments like this are indeed what make reading Slashdot worthwhile.
Only 37,964? (Score:5, Interesting)
Re:Only 37,964? (Score:4, Insightful)
I didn't bother to RTFA, but is this guy talking about 37,964 intelligent species, or 37,964 different civilizations? Because if our little planet is anything to go by, a single species can have multiple civilizations, concurrently. Depending on how you count them, there are up to 245 different civilizations just on earth.
Life isn't Star Trek, there's no reason we should assume a single species has only a single cultural heritage for itself.
Re:Only 37,964? (Score:5, Insightful)
Because if our little planet is anything to go by, a single species can have multiple civilizations, concurrently.
Based on how alien alien civilizations probably are, I imagine everything from Wall Street to bush men will fall under "human civilization" and the point you're trying to make would look as meaningless as saying you and the guys on the other side of town live in different civilizations.
Comment removed (Score:4, Interesting)
Re: (Score:3, Insightful)
What is the problem with more activity as long as you can get away? It's not like stars crashes into each other every millionth year or so is it?
Wouldn't the extra radiation if any increase the number of mutations (if they worked as life on earth) and thereby increase their development speed? Same with shorter generations I guess.
Re:Where to find them? (Score:5, Informative)
Not sure the plausibility or not, but we're ALREADY in the outskirts of the galaxy.
Re:Where to find them? (Score:4, Funny)
we are at the outskirts.
and everyone knows that the rich flee to the suburbs. That goes in line with civs that flee the core.
Re: (Score:3, Informative)
My estimate (Score:5, Insightful)
1.
And it is as valid as this astronomer's estimation.
Re:My estimate (Score:5, Funny)
1.
Is that the mice, or the dolphins?
Re:My estimate (Score:5, Informative)
Re:My estimate (Score:5, Informative)
Re:My estimate (Score:5, Insightful)
Re: (Score:3, Insightful)
I agree there, but until we can cure ourselves (human society, as a whole) of the reasonably ridiculous notion that life began here when some mythical magical man in the sky waved his hands on a whim, we (as that society) are never going to actively and definitively search for that understanding.
Because we are a generally religious planet, we are no better at figuring out how we got here than illiterate barbarians looking to their shaman 10,000 year
Re: (Score:3, Interesting)
Truly, I wouldn't consider the human race to be intelligent until we decide to look around us for answers based on available evidence. I know we do some of this already, but way too many of us are willing to just simply "believe" what we're told by others who don't really know either.
The sum of human knowledge is too great for us to consume in one lifetime while also sustaining ourselves.
To do this would be to sentence our species to stagnation.
Trust must be placed in experts because of this.
Re:My estimate (Score:5, Interesting)
....but way too many of us are willing to just simply "believe" ....
There is no way you can live your daily life without belief. When you get into a car or a plane, you BELIEVE that they will take you where you want to go. You don't know that for sure. When you go to bed at night you believe and hope that you will wake up in the morning but there is no guarantee that you will. I am sure that you have at one time or another read stories of whole families who went to bed in the evening and never saw the next day due to fire or carbon monoxide. Our lives are governed much more by belief, by faith, than the sure knowledge.
There really is no proof of anything, only evidence that we can choose to believe or not believe.
(...of the reasonably ridiculous notion that life began here when some mythical magical man in the sky...)
You and everyone else that agrees with your assumption (belief) doesn't really KNOW this, but simply believes it and then tries to pass that belief off as sure knowledge. The only evidence we have, is that life, that we are here. There is no way to do deduce from that alone how it began. Even if you invented a time machine and used it to travel back as far as necessary, what evidence would you collect there at the beginning, to bring back to convince your fellow humans at the present time? In the end, whatever evidence you did collect and bring back, would still have to be believed. It would not constitute incontrovertible proof.
If an intelligent life form came to visit us here on planet Earth, what evidence would be sufficient to convince us that this entity came from a galaxy far far away or even another universe or dimension?
Then where are they? (Score:4, Interesting)
The "famous Drake equation" is NOT meant to calculate anything, it's meant to start a conversation on what the parameters of intelligent life probability are.
On the other hand, the famous Fermi Paradox [wikipedia.org] tells us that we're alone in the galaxy. And considering that's a direct piece of data, I tend to believe this view. People like to wave their hands and say, but, but, WE'RE here! That means that there "just have" to be more! Why are we so unique? This is the Sagan argument, and it's answered by the Anthropic Principle [wikipedia.org].
And yes, in this case, absence of evidence *IS* evidence of absence.
Re:Then where are they? (Score:5, Informative)
Or there is of course, another possibility: That humans are the only "intelligent" species using radio transmission as a communications medium and that any other "intelligent" species is such a great distance away and/or in a region of space where we haven't been listening that we are unable to detect them.
Re:Fermi paradox (Score:3, Insightful)
Re:Fermi paradox (Score:5, Interesting)
You're missing an entire aspect to the Fermi paradox.
The universe is old. VERY old. About 14 billion years. Earth is fairly young, about 4.5 billion years.
Assuming intelligent alien life take about as long as intelligent Earth life to evolve (give or take a billion years), these other civilizations would have billions and billions of years ahead of us.
Re:Fermi paradox (Score:5, Insightful)
Correct me if I'm wrong here, but an Earth-like planet couldn't have come about much sooner, since we need so many elements that we can only get from old burned-out stars. There's gotta be a lot of cycles before there's enough material further up the atomic chart to make an interesting planet.
Re:Then where are they? (Score:5, Interesting)
For example, we can only just see a planet that seems to be rocky and atmosphere-bearing, which therefore meets some of the criteria for "life as we know it". We've been able to see gas giants, which might harbour life as we don't know it, for a little while now. However we can't actually resolve giveaway cues for planet-spanning civilisations, never mind lower life, either kind of planet yet. And we have no reason to assume that they'll be "chatty" in any way we can detect over long distances. To a group of aliens flying through alpha centauri whose civilisation skipped radio and went straight to fibre optic and laser, 2000AD Earth and 200,000BC Earth would be indistinguishable.
Re:Then where are they? (Score:5, Interesting)
Well, I'd say the main issue with that argument is that we just plain don't have the tools to detect intelligent life outside our solar system.
Radio signals are not the only way to detect intelligent life. I think the biggest ramification of the Fermi Paradox is that we're here at all. When you do the math, even at sublight speed, it takes about 10 million years to fill a galaxy (give or take an order of magnitude) using geometric progression. That's *nothing* in the billions of years of the life of the galaxy. Yes, maybe a lot of civilizations wouldn't have expansionist goals, but it only takes one. Only one civilization has to have the desire to expand in a sublight sleep ship and the whole galaxy is filled before we even arrive on the scene.
Or, at the very least, someone would have sent out Von Neumann self-reproducing intelligent probes. We should see those everywhere, if life were common.
People hate facing up to the fact that we're alone. But it just seems to be the fact of the matter.
Re:Then where are they? (Score:5, Interesting)
Or, at the very least, someone would have sent out Von Neumann self-reproducing intelligent probes. We should see those everywhere, if life were common.
probes with bacteria or virusses, or even just amino-acids ?
Re: (Score:3, Interesting)
Re:Then where are they? (Score:5, Interesting)
As always, no. (Score:5, Insightful)
Because a species of intelligent dolphins would surely be detectable from their radio transmissions.
No. That entire line of thought is based upon the incorrect assumption that WE are the model for all other species.
We're almost unique on Earth. Where we share DNA with every other animal. Why expect that from creatures who evolved on a different world?
Not to mention the incredibly SHORT time we've been looking over an incredibly SMALL portion of the galaxy.
Your entire argument is based upon another species developing the exact same technology that we have ... and using it in a fashion we can detect ... far enough in the past ... but not too far in the past ... so that we can detect it ... using the technology we have ... during the time we have been trying to detect it.
Yeah, like that "proves" anything.
Re:As always, no. (Score:5, Funny)
I've seen a lot of Stargate, and if I've learned anything, it's that pretty much all alien life looks like us, develops civilizations nearly identical to our own history, and speaks english.
You need to do more heavy research!
Re: (Score:3, Funny)
That theory is backed up by Star Trek. Where there are few alien civilizations that differ than us in their appearance, and they too all speak English (Some of them have their own language, like the Klingons, but they can all speak English very well)
Re: (Score:3, Interesting)
Well, by 'why haven't we detected their radio transmissions,' there was no intelligent life on planet Earth until the late 1800s.
And I can very easily come up with a scenario where a civilization as advanced as us wouldn't bother using radio. It involves a planet with high background EM interference, a tradition of using visual signals, such as semaphores, which then evolves into using light-based communication, ending with everything long-distance being laser-based, or something else..
Re: (Score:3, Insightful)
Please define exactly what evidence we should be looking for. Until that is done, absence of evidence will NEVER be acceptable as evidence of absence. There is simply way too much that we do not know about the nature of life, it's origins or it's potential manifestations. Bit of pot calling the kettle black there Mr Hand Waver.
Re:Then where are they? (Score:5, Informative)
Sorry, but the logical fallacy police have to intervene in this one. Absence of evidence is indeed evidence of absence; however, it is not proof of absence. In this case, as has already been demonstrated, we would need significantly more evidence of absence before we could come to any sort of meaningful conclusion. The current evidence of absence is about the equivalent of saying we know there's not a large ET base on the surface of the bright side of the moon.
Further, there's nothing logically wrong with the pot calling the kettle black. The kettle is indeed black regardless of the color of the pot. It just makes the pot look dumb for trying to make fun of the kettle. It reminds me of this quote attributed to Jack Nicholson:
"My mother never saw the irony in calling me a son-of-a-bitch."
Re: (Score:3, Interesting)
On the other hand, the famous Fermi Paradox [wikipedia.org] tells us that we're alone in the galaxy. And considering that's a direct piece of data, I tend to believe this view.
From a human point of view I find the Prime Directive has some basic sense behind it. Arguably we Westerners shouldn't have interfered in Africa, for example, and introduced stuff that disrupted their own culture and put a spanner in the works of them developing in their own time. Of course our planet is small and we couldn't help but interfere. Interstellar space is another matter. To take the argument further, before we could see planets in deep space, we thought this was evidence that they were rare. Bef
Re: (Score:3, Insightful)
That's not an answer. It's a tautology. It amounts to "We are unique because the universe was tailored to produce us", which itself amounts to "We are unique because the universe exists", which itself amounts to "The universe exists". It's not so much an answer as it is the ultimate expression of vanity.
The Fermi paradox and Drake equations are not predictive tools. They are not predictive because we have no estim
Re:Then where are they? (Score:5, Informative)
Sure, the signals have travelled a long way. Now, would you like to be the entity at the other end trying to pick out our signals from all the other noise that exists in the Universe?
Since the power of the signal is reduced by the square of the distance, when we start talking about interstellar distances, (forget intergalactic distances), that number is so large as to make our signals virtually undetectable. The CLOSEST star is Proxima Centauri which is 4.2 light years away. Convert to meters, we have approximately: 4 * 10^16 meters. Squared gives us a power reduction of 1.6 x 10^33.
So, if we sent a terawatt signal, 1x10^12 watts, even if there was someone at Proxima Centauri to listen, they would have to hear a signal that's 6x10^-22 watts. Which is pretty hard to pick out from any background noise.
Re:Then where are they? (Score:5, Informative)
A terawatt signal radiating uniformly would produce 1e12 / (4*pi*(4e16)^2) w/m^2 = 5.0e-23 w/m^2. With a dish the size of Arecibo (7.3e4 m^2) that's -144 dBm (decibels referred to milliwatts). For comparison, the received GPS signal strength is ~ -133 dBm. With a slightly narrower bandwidth, or signal processing techniques that can work at lower SNR (eg looking for a carrier wave over extended periods -- exactly the sort of stuff SETI@home does) that extra order of magnitude isn't hard to come by.
Note that there are efforts ongoing to build larger area arrays (eg the square kilometer array), improve reciever electronics (chilling the front-end amplifier lowers the inherent amplifier thermal noise, for example), and improve signal processing techniques. Also, for certain types of transmission, the 1TW estimate isn't unreasonable -- Arecibo has radar transmitters with as much as 20TW effective isotropic power (lower total power, aimed at a small fraction of the sky). Given the right sort of source signal and extended observation, something like Arecibo could see some of our leakage signals, not just intentional transmissions.
Suspiciously absent (Score:5, Interesting)
No mention of species less advanced than us, but there are apparently 37,964 more advanced. I wonder why that is... Other civilizations must look at this backwater hick-world and laugh.
Re: (Score:3, Funny)
If Trainspotting's taught me anything, it's that the Scots have a severe sense of self-loathing, after being colonized by "wankers" for centuries. So it's really not surprising that a Scottish astronomer would assume that other species are more advanced, rather than less so. I'm sure his English colleagues would (uniformly) disagree.
Re: (Score:3, Funny)
Re:Suspiciously absent (Score:5, Interesting)
Which is why they send us all the UFOs. I know that serious people like to dismiss UFO reports because of how over the decades we turned the whole topic into ridicule, and the masses of loonies interested in the topic didn't help, but you have to remember that lots of very well documented UFO events reported by military personel and pilots are far from explained by anything we know.
You can scoff off the whole UFO thing but you can't take a precise case (provided it's a good one of course) and explain the recorded flight paths and phenomena.
That's what strikes me regarding the SETI approach vs UFOlogy, we look as hard as we can hundreds of light years away, yet we can't be bothered to take a closer look at what happens in our own atmosphere. I'm not implying that any recorded UFO event is extraterrestrial in origin, but in many cases you have to consider this possibility by an absolute lack of alternative explanations. No matter what I think it's worth a better scientific examination of the whole thing. But unfortunately the scientific community devotes more time and energy to what it considers safe research, which is why we spend so much time in the cul-de-sac that is string theory while investing very little in seemingly more risky possibilities (the Garrett Lisi example springs to mind).
Breaking news! (Score:4, Funny)
It's now 37,962. The Qnak'k'z of Kuberon II just set off a prototype nanoplasmic bomb that wiped out the whole planet. The timid and peaceful Fnumri of Kuberon VI's third moon were not directly affected, but the flash gave them such a fright they all died of double heart attacks. Sad indeed.
The real answer (Score:5, Insightful)
We just don't have a clue.
The number of things we don't have a clue about is staggering.
Counting the number of earth like planets is just plain silly. If life can only start in space and then find a planet, earth might be totally unsuitable for the first start. It also presumes life can only exist under earth like conditions yet we KNOW that even life on earth varies widely. If some species can survive on the bottom of the ocean outside the influence of the sun, is it impossible to imagine a lifeform that exist in space itself?
No, I am sorry but until we can actually go and look our estimates of the number of civilizations is between 1 and 1+.
Re:The real answer (Score:5, Interesting)
The biggest problem I see with this person's claim is that panspermia doesn't really work well when applied to reality.
There was an experiment discussed on Science Friday where an experimenter said cosmic radiation does a good number on genetic material based on tests with actual genetic material. I think they showed that in about 80,000 years, genetic material is just broken up into a bunch of tiny, useless snippets, especially if it's on a rock passing between stars, there is much less protection against radiation than there is within a star's heliopause. Panspermia might be a workable idea for passing organisms and code between planets in one solar system, but not for interstellar travel.
Re: (Score:3)
> There was an experiment discussed on Science Friday where an experimenter said cosmic
> radiation does a good number on genetic material based on tests with actual genetic
> material. I think they showed that in about 80,000 years, genetic material is just
> broken up into a bunch of tiny, useless snippets, especially if it's on a rock...
Not on a rock. In it. Bacteria have been found thousands of meters down in the Earth living on hydrogen produced by radioactivity.
> ...passing between stars
Re:The real answer (Score:5, Insightful)
There is no prove one way or another that oxygen is needed for instance to create life
Incorrect. Life caused the Earth's atmosphere to have oxygen. There are still life forms here that oxygen is a deadly poison to.
Re: (Score:3, Informative)
How, pray tell, did cyanobacteria consume carbon dioxide and release nitrogen? Biological creatures (that we know of) do not perform fission or fusion.
From an article at MIT [berkeley.edu]:"Many Proterozoic oil deposits are attributed to the activity of cyanobacteria. They are also important providers of nitrogen fertilizer in the cultivation of rice and beans. The cyanobacteria have also been tremendously important in shaping the course of evolution and ecological change throughout earth's history. The oxygen atmosphere that we depend on was generated by numerous cyanobacteria during the Archaean and Proterozoic Eras. Before that time, the atmosphere had a very differe
Advanced? (Score:5, Insightful)
But we have no definition of advanced.
Look, just because an alien civilization has been around longer than we have, doesn't necessarily mean they will be more advanced than we are.
Maybe they could have been around one million years before us, but are stuck somewhere between Mesopotamia and Rome.
Re:Advanced? (Score:5, Insightful)
Re: (Score:3, Interesting)
Actually we don't even have a satisfactory definition of "life". Just look at the heated arguments about artificial intelligence or abortion to get a flavor for the lack of consensus on the issue.
There may be organizations of matter that are highly complex but not obviously sentient. Maybe species that are so long-lived and slow-moving that we overlook them as just another rock. Or maybe their composition will be so different (crystal? glass? gas?) that we will dismiss them. Or maybe they will be fairly sim
My assessment (Score:5, Insightful)
I am a polar bear. Don't bother to ask me how I managed to get on Slashdot and post this, you would never believe it.
However, I have been doing some estimations of my own. I have always wanted to figure out how many polar bears there are in the world. In my neighborhood here in the arctic, there aren't too many polar bears. About 350. I estimate that we roam over 20 square kilometers. Now, based on some observations I made from the bottom of a well, I figure the earth is around 500 million square kilometers. I haven't actually been outside of my corner of this world, but I imagine everything must be like it is here, and life must be exactly like it is here. I have no evidence to the contrary.
So, I figure there must be 25 million times 350 polar bears or 8.75 Billion of them.
Re: (Score:3, Funny)
Nevermind all that. Do you know know what apples is?! And if so, how?
Re:My assessment (Score:5, Insightful)
And since you miss the big point, I will spell it out.
A polar bear is using the limits of his logic to speculate on the world as a whole. Had an intelligent bear been allowed to travel the world, he would see where his equation breaks down.
An intelligent human attempts to speculate about the universe as a whole. He is smart enough to realize that he has no clue about how often intelligent life occurs on "habitable" worlds, so he plugs in a variable, then proceeds to put in numbers for something he has no clue about. Since it is unknown, his number is bullshit. Drake realized this, but countless amateurs have treated these numbers as the gospel and wildly speculated about the unknown. this in and of itself isn't bad. However when folks put weight on these numbers, it is bad.
Just as the polar bear has no real clue about the planet it lives on, we have no clue about the universe we live in. I hope that as a civilization that we go out and really begin to explore this place. But as long as we are sitting here on earth, killing each other, and wasting resources on there here and now, we cannot jope to fathom the way the universe truly is.
Close neighbors? (Score:5, Insightful)
But, the diameter of the milky way is about 100,000 light years - so, if we assume that pre-Galileo civilization was oblivious to ET, we as a species are only aware of civilization signs within 400 light years or so.
So, if there are 40,000 civilizations within a 100,000ly diameter, then there are approximately 2.56 civilizations within a 800ly diameter.
Personally, I feel like Earth represents the .56 of a civilization in that scenario...
UK Ministry of Defense publishes UFO Reports (Score:4, Funny)
http://edition.cnn.com/2008/WORLD/europe/10/20/britain.ufo.sightings/index.html [cnn.com]
How many of that have stargates? (Score:4, Funny)
How many of that have stargates?
You won't find them (Score:5, Interesting)
Ephemeral civilizations have only a short time to detect each other; I doubt that happens often.
Re:You won't find them (Score:4, Insightful)
The instinct to reproduce and grow in numbers is fundamental to all life. To "hole up" is to accept death as the local star fades--contrary to the most basic life instinct.
Advanced civilizations don't "hole up," they spread.
Re:You won't find them (Score:4, Interesting)
Considering that we are not ourselves members of an advanced civilization I don't believe we can say what they would do.
I imagine that even an advanced human civilization would be pretty incomprehensible to us.
The instinct to reproduce and grow in numbers is fundamental to all life.
Try telling that to today's first world societies. How many of them have negative net native population growth? So why couldn't an advanced species settle for zero population growth or even negative for a few hundred thousand years (e.g. if they did start out colonizing and then thought better of it).
To "hole up" is to accept death as the local star fades--contrary to the most basic life instinct.
...aproximately 5 BILLION years later...(or whatever) Assuming you haven't managed to figure out a way to stabilize it using, you know, your advanced civilization's technology. (reminds me of the new dr who series where they went to see earth being destroyed) Or that one couldn't wait until 10K years before catastrophe and just pick up then....etc.
Advanced civilizations don't "hole up," they spread.
cite needed, i think. :)
What's more likely is that an advanced tech society treats any form of uncontrolled emission as lost power. Sound, for example is an indication that you are losing energy. Broadcast EM spectrum waves may be similarly treated. They are not likely to be spewing massive amounts of powerful EM in all directions and certainly aren't likely to be shining massive laser/microwave/xray/neutrino/?? comm beams and such at random spots in the sky - that stuff'll be point to point and they'll even most likely recapture the transmission energy.
So, even if they spread out, there would be little way to notice them unless they get on a "call your friends when drunk" jag while we happen to be listening.
Precision != accuracy. (Score:3, Informative)
They can be as precise as they like, and revise their estimates to 361.055371 (or 31573.22 or 37964.0000) if they want. Precision without accuracy is worthless.
At least they estimated distributions for some of the parameters. My favourite part was the honest phrase "the model now enters the realm of essentially pure conjecture" when they moved to considering the life parameters. Probabilities and uncertainty estimates here should have been of the NaN sort.
Alas, they then proceeded to assign finite uncertainties to unestimable quantities. The standard deviations they actually gave are merely parametric, with the assumption that the underlying model structure is valid. Given that they obtained very different values from three different models (all of which may be wrong), the true uncertainty is far higher. An estimate of a value accompanied by an estimate of its uncertainty - with the estimates depending on pure conjecture - does not convey anything approaching accuracy.
Of course, if the numbers are just for fun, or for dinner conversation, that's fine. As scientific estimates, they should be discarded.
A few quotes from some famous people: (Score:3, Funny)
God: Bender, being God isn't easy. If you do too much, people get dependent on you; and if you do nothing, they lose hope. You have to use a light touch, like a safecracker or a pickpocket.
Bender: Or a guy who burns down a bar for the insurance money!
God: Yes, if you make it look like an electrical thing. When you do things right, people won't be sure you've done anything at all.
If it had (Score:3, Interesting)
Up until the last year or so ago all they could detect was gas giants orbiting distant stars. Now the technology has advanced to the point that they can now detect smaller rocky planets too.
I look at the plethora of life on Terra and it's hard not jump to the conclusion that if there's liquid water, there's life of some sort. Doesn't even have to necessarily be liquid water too. Hydrocarbons would work.
The number is 0 (Score:4, Insightful)
Or 4352342. "Calculating" any such number is not in hardly more scientific than throwing dice to figure it out. Sometimes I wish scientists wouldn't have this urge to make the impression of having a clue, when, quite obviously, the don't have a clue. Or, as in this case, provably cannot have a clue.
Now one knows yet how life came into being. Stop making calculations that require knowing that to even get close to meaningful numbers.
Re:my theory is 1 civilization per galaxy (Score:5, Funny)
I follow the Mass Effect way of thinking. A handful of civilizations, each with dramatically polarized stereotypical traits, and who speak English with perfect North American accents, regardless of the structure of their mouth(s) and/or vocal cords (assuming they have them...).
Re: (Score:3, Insightful)
Comment removed (Score:5, Funny)
Re: (Score:3, Interesting)
Then you start relying on deliberate lighthouse efforts.
There is also a small matter of the inverse square-law.
Re:What about T I M E ??? (Score:4, Funny)
With NTSC analog TV going away next year, one of our big identifiable sources dies
True, but any alien civilization that has been viewing our broadcasts has been given fair warning of the switch and have been told where they can obtain a digital receiver box with a government coupon.
Re: (Score:3, Interesting)
Take the Voyager data as a nice proxy measure of long-distance communications. With our best RTs looking in exactly the right spot, its 3W of power and moderately directional antenna could barely send 110 baud from the orbit of Pluto. Crunch, crunch ... that means that an ET lighthouse at 1000ly needs to be transmitting 75 GW (or have equivalent antenna improvements). How likely?
Re: (Score:3, Interesting)
In any case, it would need to be 75 GW of power using the same receiver as was originally used with Voyager. Is it better today? My guess is that it is. We keep getting better responses out of the same bandwidth because our sensitivity to the signal increases. I bet you that NASA engineer looks back at the 3W/110 baud numbers with
Re: (Score:3, Informative)
You don't need FTL for star travel, even travel on the scale of current human lifetimes. You just need to accept that you can't go home. Relativity is a blessing, not a curse. Do the math and you will see that with 1G of acceleration you can reach any part of the universe in a reasonable amount of your time.