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Number of ET Civilizations In Our Galaxy Is 37,964
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."
Make that 37,965. My colleague surely has one growing in his tea cup.
yuck.
...of spurious precision.
It's all in the subject stupid!
The drakes equation really isn't thaaaat useful since its filled with made up values we really can't guess at. BUT its lots of fun, everyone throw in their own numbers that have some personal truthyness to them and see what you got. I get around 43,012
Should give us plenty of room to screw up without affecting anyone.
The simple truth is that interstellar distances will not fit into the human imagination
- Douglas Adams
I'd be interested to know where the best place to look for ET civilizations is. A common science fiction theme, found in plausible for in Niven's Known Space universe and Vinge's rather implausible A Fire Upon the Deep has civilizations getting out of the core as fast as possible, settling the fringes of the galaxy. The increased speed of stellar activity in the core would make for a risky place to build lasting civilizations. Would everyone better than us be at the outskirts?
1.
And it is as valid as this astronomer's estimation.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
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 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.
And yes, in this case, absence of evidence *IS* evidence of absence.
Sometimes it's best to just let stupid people be stupid.
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.
Admit it. You post strawman arguments as AC so you get modded Insightful for refuting them, rather than Troll
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+.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
"the theory of panspermia says that there ought to be 37,964 extraterrestrial civilizations more advanced than our own in the Milky Way.""
Yes but is there intelligent life out there?
Now go ahead and try to prove me wrong ;-)
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.
I'm god, but it's a bit of a drag really...
There is one known planet that has produced life. This would be our own, and isn't really a good candidate for inclusion in our sample set because it was the one we base our hypothesis thta life exists on other planets on.
So, we can speculate that there are a certain number of stars with life supporting planets. We have some idea of how many stars have planets, and based on knowledge of extra-solar planets, we can make a stab at how many suitable planets there are, at least in terms of being in the habitable zone. So that's a start. That's also an end.
We have no idea of the tolerances for developing life. Could Venus produce a lifeform that thrives at 400 degrees C and breathes sulphur dioxide and carbon monoxide? Possibly. Possibly not. We have no idea how many planets have a composition sufficiently similar to Earth because we don't even know what "sufficiently similar to Earth" means. Even if we did, we don't have particularly good knowledge of what other planets are like.
Our civilisation has never become exinct, so we don't even have a sample set of 1 for the typical lifetime of a civilisation. We have no idea what the likelihod of our planet developing life was. It was probably somewhere between 0.00000000000000000000000000000000000000000001% and 99.99999999999999999999999999999999%. We have no idea how many will be able to or want to communicate. Too many of the unknowns are simply wild guesses.
All we can deduce is that there is at least 1 developed life form in the galaxy, and probably substantially fewer than 400 billion.
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.
Is Earth one of them?
Assnumeral and trying to calculate Pi to infinity is how we got goatse?
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.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
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...
I don't subscribe the theory that there is so many starts that intergalactic civilizations must be ubiquitous. The same perspective you could argue that Earth should be sterile, high number of stars means a supernova should have destroyed us by now. Or the number of stars in a galaxy is so huge, that when galaxies collide so do the stars, which actually doesn't happen in galactic collisions. Chances are that the problem of shortening the vastness of space is impossible to solve, life other than on Earth is as meaningless as the afterlife.
sure love to fly their UFOs and give drunken farmers anal probes and mutilate their cattle and make crop circles.
Are we sure that they are smarter than us or just more technologically advanced than us but not smarter? Then again, maybe it is just their teenage UFO drivers playing pranks on us? ;)
Remember, Slashdot does not have a -1 disagree moderation, and no, troll, flamebait, and overrated are not substitutes.
37,964's enough to start a Federation right?
Of course, with DRM, we now own them all.
today :
http://edition.cnn.com/2008/WORLD/europe/10/20/britain.ufo.sightings/index.html
Read radical news here
Certainly if enough "believers" pray about this, the answer will come to them and they can tell the rest of us the answer.
This method will help my highly religious sister believe it. She's been "taken" by one of the largest cults on Earth - the Catholic Church.
Excellent timing, I just finished a 2,000 word essay in my Slashdot Journal on the Subject of SETI
SETI Augmented with Supernova Synchronization
Letter To Iran
If we ask "where are they?", could it not be possible that NO advanced civilisation could make it to interstellar travel, given how difficult it would be to maintain a survivable environment, enough resources for the trip, and so on? After all, we can look in out neighbourhood and conclude that life is not abundant in the vastness of space, so it must need some kind of special environment to develop and grow. No matter what type of environment a civilisation may develop under, it's unlikely to be one easily recreated on a spacecraft.
Oh, now I read the wiki I see this has already been considered. Well, there's no evidence that our TV signals and such would be powerful enough to reach beyond the solar system. All our deep-space communication is done to a very precise point. Same goes for the Arecibo message, and that has many years to travel before it reaches its destination. These other civilisations would have to be millions of years ahead of us for us to hear them now.
Why speculate on any hypothesis, which needs to be tested to be worth anything? (aka science) What's intelligent life, what is life? All big questions. Most of us on earth believe we are idiots, and have some intriguing evidence. ( Bush reelected, for example ) However; until you meet the thugs on Jupiter who can lift a tank, while being shocked with lightning and 200 mph wind.... maybe rednecks aren't so bad. I believe personally, our limited ideas are missing various things everywhere. Believing only the limited senses humans have can determine where life is. Existing behind everything, are things we cannot perceive. Dark matter, things beyond our microscopic visual, audible, sensory ranges exclude most of the universe. Let's start up our spaceships and take a look around kids! I'll start /. Alpha Centuri ( only 4 light years away ) We'll put a few on a friends list, chat, and /. Then they can discuss this with us...
It's 2 ^16 making it 65,556 incidentally.
How many of that have stargates?
Michael Crichton criticised the Drake equation years ago:
http://www.crichton-official.com/speech-alienscauseglobalwarming.html
My personal guess is that there are OVER 9000 civilisations out there.
Squirrel!
Was anyone else just a little sad that the bitches didn't arrive on the 14th a few days back?
Already our own emissions have "degraded" from an easy-to-identify analog central-frequency, to digital spread-spectrum that is much more difficult to distinguish from white noise. Expect the redundancy to reduce, making identification harder.
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
Can you really build a model and estimate the number of civilizations based on a single data point?
I agree with your calculation that Earth is a planet of half-wits. (or, 0.56-wits)
Of course, your much more optimistic than whoever suggested there were 10^-5 = 0.00001 advanced civilizations.
And 37,963 of those civilizations are more advanced than Slashdot commenters.
I guess that's not really news...
How many of them have reached the Space Stage?
How many are still Tribal? Or Civ?
I think you should consult Will Wright about this!
For how long can we assume that an ET civilization will be using/monitoring "conventional" EM band emissions?
That is the last term in the Drake equation. The Drake equation is not intended to be an estimate of the number of contactable civilizations that have ever or will ever exist, it is intended to be an estimate of the number of contactable civilizations right now.
To answer your question, I think that pessimists say 500 years, optimists say 10,000 years. But I didn't RTFA.
I need more caffeine.
My wife and I rented that the other night. It was pretty hot and I got lucky (hopefully she did too). It was an excellent use of the "undercarriage" shot.
Civilizations that manage to survive reach technological singularity, and simply hole up.
Ephemeral civilizations have only a short time to detect each other; I doubt that happens often.
Why cap the time that they will monitor it? Aside from military and industrial application most of the advancements in technology on this little blue marble over the last couple of thousand years have been for the purposes of observing and recording the data. History, in its many forms, has been the motivation of a lot of technology. We write down pretty much everything we see.
Take that into account with the increase of our ability to monitor more and more without actual human intervention and we can see where this is going. In another 100 years the entire efforts of SETI will be probably available to every child much like a cheap telescope or a chemistry set. Can you imagine where SETI will be at that point if it still exists? We will have machines that will monitor and dissect every single bit of data it can in the electromagnetic spectrum with no or next to no human interaction and all for less of the costs than what a single dish in the VLA costs per year in maintenance. We will be awash in all this data and without proper scientific reasoning we will never stop processing this information.
Dedicated Cthulhu Cultist since 4523 BC.
There are as many civilisations as there are.
The Drake equation is kind of interesting, but ultimately fruitless. Most of the variables are poorly understood. Arguing over the answer to the Drake equation has become the modern equivalent of arguing about the number of angels you can fit on a pin head.
There is an assumption that the equation is correct, but we can't know that until we actually get to measure the reality. There may be factors that no-one has even considered and are not part of the equation, and the factors we do know about are no poorly understood as to be worthless.
This is a perfect of theory obsession. It doesn't matter how good, or elegant, or clever a theory of reality is, at the end of the day if it's wrong, it's wrong.
In science, the final arbiter of truth is always the Universe itself.
Paul
Paul Leader
I think I'd rather have an estimate of the total number of stars and time rather than a current "formation rate" which may or may not be representative of the formation rate 4 billion years ago.
What do you mean? A single data point is one more than you need.
Science tests beliefs (hypotheses) against evidence.
Religion tests evidence against belief.
Notice the difference?
Your ridiculous attempts to make the vague wording of a Bronze Age myth fit modern interpretations of the evidence are the wanderings of a deranged mind.
Your points are pretty weak - "Let there be light" invokes a mythical being without adding anything at all to the idea of a big bang, "suspended from nothing" really, really means nothing (think about it carefully), "tells of the continental drift" would really be amazingly prescient if it wasn't based on a weird interpretation of about two sentences in Genesis plus some spurious calcualtions by a Creationist with access to a computer, "makes reference to the world being round" isn't really surprising, as the Babylonians knew that before Genesis was written, "110 civilisations have a flood story" isn't at all surprising given that sea levels rose globally after the last ice age, and finally the assertion that Genesis has an account of the development of plants (rather than 'God made them') is nonsense.
Go and troll somewhere else, please.
One swallow does not a fellatrix make
Then you start relying on deliberate lighthouse efforts.
There is also a small matter of the inverse square-law.
Based on Actual observed evidence, as opposed to rampant speculation, we know that there are exactly 1 life-sustaining planets in the universe.
Since we already know where that one is, it is a simple matter to extrapolate the evidence and determine that there are exactly 0 ET civilizations in the universe right now.
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.
Those who can make you believe absurdities can make you commit atrocities. - Voltaire
âoeThe results of simulations like this are no better than than the assumptions you make in developing them. And these, of course, are based on our manifestly imperfect but rapidly improving knowledge of the heavens.â
Right. That's the key point. The knowledge may be "improving"â" and some of the parameters are now becoming knownâ" but many of the numbers that go into the Drake equation have an uncertainty of "nobody knows" or, "there are a lot of different speculations that can answer that question, but nobody has any good data to favor one hypothesis over another."
http://www.geoffreylandis.com
The Drake equation is flat out wrong.
We shouldn't be guessing at the number, we should be guessing at the probability of then calculation of distribution of various predicted forms of civilizations.
I hope JJ is up to it. :)
But the sensitivity of new monitoring equipment is only going to increase. That's the entire reason we can afford to use such a weak signal to begin with. I don't know if there is a finite end to what will be observable but I won't hazard a guess as we've seen such proclamations proven false in the past.
Dedicated Cthulhu Cultist since 4523 BC.
Carbon based life forms exist for a reason. Other strange biochemistries don't work. If you want to prove otherwise, then go ahead and do your own Miller experiments. Otherwise, you're just another know-it-all.
Happens when you play Pan's flute too long.
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.
At the bottom of the
"Space is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." -- Douglas Noel Adams (b. 1952), British author, "Hitchhiker's Guide to the Galaxy"
But, and this is a biggie, because it's so fscking huge, unless we invent some sort of FTL travel, it's unlikely humanity as a species will have any opportunity to interact with them.
... and today's pet project has
Indeed. Succinctly: http://xkcd.com/384/
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.
A fool throws a stone into a well and a thousand sages can not remove it.
It is entirely plausible that a civilization could be a billion years ahead of us.
Nerd rage is the funniest rage.
If the number came out to 32,768 I'd be a little suspicious being that it's 2^15.
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 argument that we are unique life forms is that Earth has not encountered a self-repulicating space ship. An advanced civilization would send one out, at the next solar system, it makes 2 copies, and repeats. This is a highly effective and cheap way to explore the universe. And solves the problem of not having a biological entity travel along or go the speed of light problem. But we have not found a von newman machine or an old mine to make a new machine or remains of the machine left behind, to monitor the system.
but the real question is how many are registered to vote in Chicago?
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.
Signal analysis will become more advanced, but you still need radio telescopes. That's if you're looking for RF emissions. I don't think everybody is going to have a radio telescope in their backyard.
Although I sometimes question our own intelligence, wouldn't the lower bound be... uh... 1 and not the 10^-5 in the post?
And why not? I'd really like to see someone back that up.
Dedicated Cthulhu Cultist since 4523 BC.
43
That is how many KNOWN INTELLIGENT RACES there are in the universe. In our Galaxy there are only 12 (currently).
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.
Never mind what's out there. If there are 37,964 extraterrestrial civilizations which are more advanced, I want to know how many terrestrial civilizations are more advanced.
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?
The question is not about them detecting us. It's about us detecting them. There might be several species within 50 lightyears laughing their asses off at old sitcoms while not sending anything in our direction that we can detect.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
You're right, it is bad when you put too much weight on these numbers, and use them for something practical. Most people just laugh and ignore them. John McCain, unfortunately, spent all of his advertising budget on 38 thousand swing planets. Boy is there egg on his face now.
It's rare that you're presented with a knob whose only two positions are Make History and Flee Your Glorious Destiny.
There are several thousand more advance societies within a thousand miles of Scotland.
Of course if he had been in Alabama then the number would have been higher.
An Eye for an Eye will make the whole world blind - Gandhi
I think it would also be hard for civs to even find each other.
Now let us presume that each civ is also actively trying to find other civs over a longer period of time. We have been searching for what, 30 years and we already want to give up?
If the others have such short attention spans as we do, we might as well stop now.
Also the closest star is 4,5 ly away. Our radio messages have just reached them.
If there are really just 2.6 civs in a 400 ly area, it might take a while to find the right ones.
It is like doing a portscan over thousands of ips with a ping of 800 years, searching for only 3 open ports.
Not to mention if I think about us being neighbors, they might have all moved away into gated communities.
So we barely blasted a few waves at some systems we think might have life and the signal barely has gone out 30+ly.
About flying saucers, someone (Drake?) compared the density between two solar systems to two bees over Europe.
Imagine that in a 3d space.
People think some space civ will take a really wild adventure and build a ship, pack people into it and ship them out to some planet that *might* have someone on it.
Now ships are not quite as fast as radio waves and by the time the ship reaches them there might not be a system left over. Or if they do reach them and no-one is home, they have to fly back.
If there is someone home they would have better luck because you never know if the place you left will be there when you get back.
Just like with the portscan it would be a lot more logical for them to send out probes.
Maybe *we* should do that? Ach we can ship out multiple to each system, because I can only imagine getting across the void might be a little harder and dangerous then getting across downtown traffic.
I hope no one starts off with the paranoid 'the aliens are out to get us' stuff.
Let's leave that to the republicans.
Where did you find the figure of 1000 ly? I was wondering about this myself and if you have someone who put that together I would be interested in seeing their numbers and logic.
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 nostalgia and laughs on the same level many of us do about the 640k of RAM claim.
Dedicated Cthulhu Cultist since 4523 BC.
OK so there are at least 300 ET civilizations. Or should I say "on order of 100 ET civilizations." So where are they?
We have only two things we know for sure about technological civilizations (1) They are possible because we know of one. and (2) They are very hard to find because we've not found another one.
The Drake equations ignores half the data we have about ETs. The parts about them not being here ("Here" meaning all the places we've looking using SETI) there should be a way to combine Fermi's idea with Drake's to come up with a better estimate.
... our 37,964 overlords.
now we need to go OSS in diesel cars
Or, of course, we could just be so primitive that radio is to them what semaphore flags are to us.
VLC FOR MAC IS DYING! IF YOU DEVELOP, PLEASE SAVE IT!!
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.
The Internet is generally stupid
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.
That's the risk of showing up fashionable late to a party. There's always the chance that everyone else will already have gone home.
Wanted: witty unique signature. Must be willing to relocate.
So let me get this straight... This astronomer has proven that if you make up some numbers based on one of a set of unproven hypotheses and feed that into an equation based on one or more other unproven hypotheses you can get a number out with 5 significant figures? The art of data production via anal extraction has reached new heights.
That's the real issue. If there's a margin of error of 90+%, the estimate is just another of the many shot-in-the-dark Drake approximations made over the years.
That is all.
What are the error bars? Don't say 37,000 to 361. That's the variation between different theoretical scenarios. But real results have to be based on experimental inputs, not just theoretical guesswork.
The usual way of computing error bars is to look at the statistical variation of the data, to infer a distribution of likelihood for the results. Problem is, we have only ONE data point (i.e. us), so the variance of the inputs is infinite.
Even if you estimate 37,000 civilizations in our galaxy, how many are within 100 light years of us? Based just on the ONE data point we have, they would have developed radio and TV within the last 100 years, so we could only hope to detect them if they are within about 100 light years. Plus or minus infinity.
"Education is not the filling of a pail, but the lighting of a fire." -- William Butler Yeats
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.
Not true. It's quite possible to observe signals from much farther away; it's only a question of sorting through them to see if any of them look like evidence of intelligent life. There's no particular reason to think that they must have started transmitting at the exact moment that Galileo did his experiments.
Where the relationship between time and distance matters is when you want to communicate with those civilizations, or determine whether they are close enough to detect our signals.
There is another issue about distance that is completely independent of how long our civilization has been capable of detecting evidence of extraterrestrial life, and that is how much power such a signal would require in order to be detected. It is probably impractical for any civilization to produce an omnidirectional signal (unless, possibly, they were only interested in their immediate galactic neighborhood), so we'd have to assume that they take turns beaming the signal to a large number of "promising" stars. The exact number depends on their resources and level of technology, but again there's no reason to think that it has any relationship to pre-Galileo civilization.
The only area where the length of time we've been able to detect such signals is relevant is that that time tends to limit the window of time that such civilizations might have been sending signals that we can detect. We've only been able to detect very weak radio signals for around 60-75 years or so, so if nobody in our light cone has been on the phone to us in that time period, we couldn't have heard them - to say nothing of the fact that given our current level of technology we'd probably also need to have our equipment pointed right at them in order to be able to hear them.
I'm afraid that all that doesn't really tell us very much, except that signals from ET civilizations must be very rare - and given the continued failure to find anything, it tends to cast doubt on whether there are such signals to detect. Either they aren't there (within a detectable distance, anyway) or they're not interested in chatting.
Every time this thought comes up, my brain falls back to musing that the Universe's dark matter is made up of Dyson spheres, and that the stars we can see are a "nature preserve".
Totally frivolous, I know. And probably easy to test false.
read these comments. we find:
1. those taking the subject matter so very seriously
2. those who take so very seriously the crusade to make sure no one takes the subject matter seriously
hey, wankers of all stripes:
it's fun to speculate
nothing wrong with that. nothing more than that. end of story
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
I tried the Drake equation once and got a result of 0.7.
In this case I still question if we have a civilization here on earth or if we still are beings with despise, hate and territorial claims more than logically thinking beings.
The last 8 years with Bush at the helm of the US hasn't proved us anything better - rather the opposite.
However - this still doesn't mean it's useless to listen. Because if you don't listen you won't hear unless it screams into your ear.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
The Drake equation has one, and only one fatal flaw. It only operates on the assumption that WE are intelligent.
Maybe they could have been around one million years before us, but are stuck somewhere between Mesopotamia and Rome.
You know... I wanted to come here and make a funny quip about the double meaning of "between" there. Something like: "Oh, like Greece?" But then I realised, you know, Greece actually IS "between" Mesopotamia and Rome in the historical sense as well, so the joke wouldn't really work...
bummer. Damn Alexander.
Even though we can say the Galaxy is very old we don't know the lifespan of a Civ. What if the average life span of a Civ is 10,000 years? Maybe their is a high chance of Intelligent life spawned on another planet dying off. Similar to Spin
.. because they are called quarks and gluons.
Hey don't blame me, IANAB
It's the most trivial equation I've ever seen. It ranks up there with embarassing things like the Hardy-Weinberg equation and the Fick equation.
Maybe exp(pi*sqrt(163))'s equation ought to become famous. The probability of getting to work is the probability of me being alive in the morning times the probability of me getting up times the probability of it being a work day times the probability of me being bothered with going in times the probability of me surviving the journey.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
Is to start manufacturing fake news of an environmental catastrophe or world wide nuclear war. Then we need to build an artificial crust over the land and sea on earth to make the earth look like a moon-like planet devoid of atmosphere. We can power out artificial sun lamps using geothermal energy. then after we build this crust about 2 miles above the regular surface of the planet we suck all the air out above it and store the air in vast underground tanks. and broadcast into space the news that our race is dying and that the nuclear war is blowing off our atmosphere. We could also cover the new crust with a bunch of nuclear waste to make it all unappealing.
We need to do this now or humanity will be dead, also setup a few stealth colonies deep within the underground of the Jovian and Saturn moons. Maybe a few in some of them in some of the outer solar system objects such as Sedna and Eris. In case they find out our ruse about earth and nuke the planet from orbit we need a backup plan to preserve humanity from the beserkers out there.
Tsukasa: All I really want, is to be left alone...
Doubtful. We already know that "dark matter" isn't just regular matter that doesn't happen to be emitting light - it's some wholly different thing that doesn't even interact with electromagnetism... meaning it's not made up of protons & electrons. So it couldn't be Dyson spheres, at least none that we'd be able to recognize as such.
Unless these conjectural aliens were made entirely of hydrogen and helium (ok, maybe a tiny bit of lithium), their home planets couldn't have formed too long before earth. There just weren't enough metals before them to form any solid bodies.
the idiotic tags have appeared again, and this time they can't be disabled in prefs for some reason!!!
what fucking information does "wedontreallyknow" tag contain? how about the fucking "haha" tag???
His calculations say that the rare-life hypothesis predicts only 361 advanced civilizations in the Milky Way now.
I'm thinking we should concentrate on making the one civ we know about "advanced" and then start working on finding out about the others. Then again what criteria are being used to determine advancedness?
Shop smart, Shop S-Mart.
Is that a /. typo or did TFA also say the estimated range of the # of civilizations starts at 10^-5 (also known as 0.00001) ?!
Because, snark about no-intelligent-life-on-earth aside, we know of *ONE*.
Here's my revised equation:
1 + (handwavy equation) = (total number of civilizations in this galaxy).
Actually, we have a pretty good idea that it's not, at least at FTL speeds. Barring some development in physics that's absolutely, completely out of left field, we know that it would take an infinite amount of energy just to get to light speed, and FTL isn't possible at all. And even at high relativistic speeds, you're talking a years or even generations to get anywhere. Who's going to pony up the cash to do something like that?
As has been pointed out above, for most of the history of the galaxy prior to the existence of the earth, there were insufficient metals (per the astronomer's definition of metals) to produce solid planets. So unless your aliens were made of hydrogen and helium, they just weren't around much before us.
The problem is that the people like you with that argument do not address the realities of inter-stellar travel.
Yes, it only takes one. But that one MUST have started MILLIONS of years ago ... and stayed DEDICATED to the task ... for MILLIONS of years ... AND SOLVED THE PROBLEM OF INTER-STELLAR TRAVEL.
Rather, it is more likely that (as we did) they will expand a bit ... then they will find other things to spend their time and money on.
Comment removed based on user account deletion
Well, heavy nuclei weren't around that long, and it's a plausible assumption that complex chemistry is a prerequisite of life. But it would be trivial for some other civilization to have a million years on us, or a few hundred million. And that's certainly capable of producing differences we couldn't begin to comprehend.
Sorry, but that just doesn't follow. I look at the plethora of houses in my neighborhood, and conclude that the entire earth must be as populated as Northern Virginia. The fact is that you need at least a few examples before you can generalize in this way.
The problem with planets is that they're always too far out, too far in, too big, too small or too much work to clean up (terraform).
And if you have the kind of tech to fix those first four problems then it's easier to just break them up and rebuild them as a series of space stations.
It's not an equivocation per se. I would presume that what you assert to be at issue (you don't specify) is the dilution of the term "belief" to cover subjects ranging from that with little empirical corroboration (religion) to that with significant empirical corroboration (accepted science).
As you see, though, these are shades of gray -- theory requires a greater leap of belief than that which is proven before one's eyes, just as logical philosophies of religion require less of a leap than do their core theistic entities.
Even across the smallest gap, though, to accept things as seemingly married to reality as the Pythagorean theorem, requires belief. It is a very small quantity of belief required for this -- but to assume you use none at all is to expend a great deal more.
Your mind is clear / The things that you fear / Will fade with how much you / Believe what you hear
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.
Um, depends on the civ/species. Some species might take a half billion year to come up with a new thought or depend on environmental conditions to drive their species's evolution. Others could learn/advance faster than we do and only take 100 years to get 5000 years farther ahead than us.
There is also the thing that a civ that far ahead could just be classified godlike and though they have limits, their kids could seed the entire rest of galaxy with random life, probes to monitor it all, and do it cheaply for an elementary school project on budget of what we'd see as what any parent would waste on any given class room project... say less than about $20 worth of effort. Now what could we do to them? Nothing. We should just be happy to be their classroom project and hope that they don't sterilize the planet when they don't need us anymore.
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.
Don't stop your thinking at the edge of the solar system. If we really assume that intelligent life takes about as long as we did to develop, we have to remember the time it took for the elements to develop and clump together. According to our current understanding, immediately following the big bang there were no elements heavier than hydrogen in the universe. It took time for this hydrogen to gravitationally condense into stars. Then it took time for these stars to burn through their life cycle to produce heavier elements--then nova or supernova to disperse them. Then it took time for the results of the novae to gravitationally collect around younger stars, and even more time for it to condense into planets. Only then do you get to the point where life as we know it could begin to form.
I'm not an astrophysicist so I couldn't tell you how long all these long times are. But I don't think a civilization could have plausibly started developing right after the big bang.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
so, where are they?
Thank you Dave Raggett
Unfortunately, Fermi's Paradox is based on postulating certain axioms which aren't that self-evident at all. So at best it's not a "paradox", but rather proof that you can reach a false conclusion if you start from a false hypothesis.
E.g., that if a sentient civilization exists, it will necessarily colonize every rock and planet in sight. I'm sorry, but while that's the bread and butter of SF, it's not self-obvious at all in the real world. Colonizing is a matter of too many factors which may, or may not, add up that way. E.g.,
1. Colonization happened on Earth only when overpopulation pressures made it happen. Prior to that, most "colonies" were merely trading posts. We were merely interested in buying cheap stuff there and selling it expensively over here, and viceversa.
But here's the fun stuff about over-population: on Earth it seems to have stopped and actually reversed in every country which has access to good medical care and sanitation. People make lots of kids when survival is a crapshot, and they have to beat the odds. If only 1 in 3 of your kids will likely survive, you make 6 to try to beat the odds and occasional flukes. But as soon as survival becomes just short of guaranteed, people first go through a population boom for about a generation, then it sinks in that they really don't need more than 1 child. They might make a second as a sort of a backup, but that's really it then. Most western countries either _are_ currently going down in numbers, or are only saved by immigration from the poorer ones.
So given an Earth where the vast majority of people can get medical care for their child, the population of the whole Earth would actually decline. It's not that far fetched, as possible futures go. Give it a billion years or so, and Earth will probably be no more than a few thousand people in a few quaint towns, surrounded by square miles of woods and nature preserves.
So there you go: that's one example of a civilization which might never have the pressure to offload its population to other planets.
2. Let's go back to those trading posts I mentioned. They happened because there was an economic incentive to. The same incentive doesn't exist yet even for importing anything from the moon.
Basically the hypothesis that we'll start colonizing all around, _depends_ on discovering some miracle engines and/or some miracle sources of energy, so hauling a thounsand tons of steel from Alpha Centauri is cheaper than making it at home. What if the physics we know now _is_ mostly correct, and that economics never works out that way? Who's going to pay for some trillions of dollars worth of a colony ship, if they don't ever expect a return on that investment?
3. (Or 2.a.) To further nail that coffin, what if FTL is really impossible? How's interstellar trade even going to happen without that? (To pay for that colony, you know.) No, please don't jump to a half-baked answer yet.
Let's say we build a mining colony only 5 light years away from Earth. Now let's say we have some damn good engines, that can accelerate to nearly the speed of light by the middle of that distance, then decelerate for the other half of that trip. (And I mean really _awesome_ SF engines there. Nuclear or even fusion don't come even close.) So it takes 10 years for a ship from there to come to Earth. It takes another 5 years for signals from Earth to get there. So from the moment you sent a "yes, I want to buy 1000 tons of steel" order, to the moment you get that steel, it'll be 15 years.
But let's say we build that colony on the idea that it will continuously send stuff, so Earth gets a continuous stream of shipments. Ok. So it takes 10 years for the colony ship to get there, let's say a year to really get the colony going, then 10 years back with the ore. That's 21 years from the moment you bought the ship, to when you get your first shipment. Are you willing to bet a trillion dollars on the idea that you'll still need that ore in 21 years?
Remember that on Earth some resources went
A polar bear is a cartesian bear after a coordinate transform.
Why can't people just drop their silly religions?
As an astronomer who has read the paper in question, a few points should be noted.
i) Forgan mentions the fact that these numbers are essentially garbage, as the input data is strongly biased.
ii) The real strength of his work is in its ability to *compare* different hypotheses of the origin of life (given the same Galactic backdrop).
iii) There are both advanced and less advanced civilisations simulated in the model (the less advanced ones destroy themselves through their own actions!).
The introduction to the paper also deals with some of the philosophical questions surrounding the Drake and Fermi formalisms (worth a look!).
That can't be right!
Life caused the Earth's atmosphere to have oxygen. There are still life forms here that oxygen is a deadly poison to.
Life caused the Earth's atmosphere to have FREE oxygen (O2). Terrestrial anaerobic life forms depend on oxygen just as much as we do--they just use it in chemical compounds other than O2. The question is whether life could form in an environment with little or no oxygen at all--like Titan for instance, or even asteroids or interstellar space.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
And did they round that number up or down in the final result?
Man, that would suck to be the civilization left out because of rounding. "Gosh darn it all, you guys are smart and all that, but numbers don't lie: You're just not advanced."
Of course, it would suck for the rest of us to have a non-intelligent lifeform (like, say, Steelers fans...) added to the list because they rounded up.
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."
Life on Earth was almost in hiatus for few billion years. It's not impossible that many other places saw conditions favorable to multicellural and, finally, intelligent life billion years earlier or so.
One that hath name thou can not otter
In contrast to micro-electronics and receivers, I do not believe transmitter efficiency has improved much. The example of Voyager is as transmitter. I don't believe it can receive anything and is running on pgming.
I don't like my white trash neighbors either... ;)
42? :D
There is another possibility. They could have gone extinct billions of years ago but we have just now heard a signal from them.
To quote a Calvin and Hobbes cartoon, sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.
'Course I'm anti-social anyway, so I probably wouldn't understand even if extraterrestrials were trying to contact me.
[snip] However, we now know that the universe is not steady-state, and in fact is quite young (13.7 Gy) [snip]
Wait...what?! The universe is the oldest fsm-damn thing in the ... universe!
There is only one Civilization and that is on Earth. (The rest most likely call themselves by some other term and call our planet an interesting collection of parasites)
there is a fundamental flaw in the drake equation, in that is operates only on estimates of probability with no consideration of the time involved. For example, if the universe is 13 billion years old, and it took 9 billion years for the first stars to create the heavier elements on which life depends, and it took 4 billion years for Earth to evolve a life-form advanced enough technologically to formulate the Drake equation, then that's...13 billion years! Which means that we might actually be alone because we're the first!
so another term is required - the number of second-generation stars in the universe old enough to have evolved intelligent life in the first place...
I believe that collapsing the equation results in the number of civilisations in our galaxy being the same number as the number of years those civilisations last.
That puts the upper bound in our galaxy at the number of years we consider ourselves to be civilised. So, the answer (arguably) is "zero" civilisations in our galaxy, including us, because we aren't civilised yet.
I put the number (personally) at less than 50, and most likely less than 2, ourselves included.
How many escape pods are there? "NONE,SIR!" You counted them? "TWICE, SIR!"
According to Wikipedia, the Milky Way is approximately 100,000LY in diameter. Using that figure against the overall probability of life in the galaxy, we can calculate the probable distance "ET" is from Earth. Using the following math--very crudely figured--I've worked the probably distance to 81.149LY away.
lowercase letters denotes sub
.5
g: Galaxy
e: Earth
Dg = 100,000
Rg = D / 2
Ag = Rt ^ 2 * pi
Ae = Ag / 37,964
Re = (Ag / pi) ^
interactive hologram, or it didn't happen.
Hmm, a virus by any other name.......think about it.
Of course all of these wild guesses are based on the kind of linear determinism found in games like Civilization & based on the antiquated and racist ideas of social darwinism from the 19th century.
Who says that "intelligent life" is a survival advantage? How does one say which society is "more advanced?" Based on our industrial western ideals of technology? Bah, if we were really smart we'd all be fat seals basking in the sun and eating fish to our heart's content.
This universe is likely infinite in size (not limited to the visible Hubble Volume) and simple probability concludes that your DNA "pattern" reoccurs infinitely. String/Brane theory predicts an infinite number of universes. Without postulating any ET's at all, the megaverse is densely populated with YOU.
It's a given (IMHO) that there is other life out there in this galaxy, never mind the rest of the universe. It could be single celled, multiple celled, animals, plant or some other creature but there IS other life out there. We are not that special in the great scheme of things. I also don't believe it will look like anything fantasized by the UFO believer crowd. The "common" "grey" drawn by people is bogus IMHO. Most likely ET will look NOTHING like man. IMHO of coarse.
A reevaluation of one of Stanley Miller's unpublished experiments on the origin of life has shown that 22 amino acids rather than 5 would were formed in the volcano apparatus he used to model the conditions that existed on Earth some four billion years ago. This should increase estimations of f[l] (the fraction of the average number of planets that can potentially support life per star that has planets that actually go on to develop life at some point). Outside of any implications on Drake's Equation, the study solves a significant piece of the puzzle on the origin of life.
You appear to accept that there were insufficient metals around... so what were these planets made of?
Bear in mind that "metals" in this context include such things as silicon, aluminum, and even carbon, nitrogen, and oxygen. Excepting hydrogen and helium (and tiny amounts of lithium), there was no matter at all in the early universe. There was nothing to make planets out of until several generations of stars had manufactured sufficient heavy elements to make them.
... dark matter could really be invisible interstellar unicorns. But a simpler explanation is that it's just some kind of elementary particle that we haven't identified yet.
If the purpose of the Drake Equation is to stimulate conversation, I wish more people would pay attention to the middle factor, fl, because it's the most significant one. The reason is that the value of the middle factor is the biggest unknown, by far.
Here is why: each of the other factors, even those that are based on singular events like the origin of life, are conceptually more extrapolatable (if that is a word):
1) Rate of star creation - multiple events
2) Stars with planets - multiple
3) Number of Earth-like planets - inferred from just a few factors (size, distance, temp, composition, etc)
5) Fraction of life that is intelligent - extrapolate from multiple events (humans, chimps, dolphins, elephants, etc)
6) Fraction able and willing to communicate - this seems almost to follow naturally from 5)
7) Persist long enough for long transmissions through space - trickier, but not too hard to imagine emergence of mature, stable societies.
4) is the big unknown. Really big. TOTALLY unknown at this point. Because once you dig a little into the chemistry and molecular biology, you realize that currently we do not have ANY comprehensive, detailed hypotheses to estimate how non-living molecular systems made the transition to self-replicating living ones.
Note the emphasis is on comprehensive AND detailed, because there are many very interesting and detailed speculations on parts of the process, such as Wachtershauser's Iron-Sulfur theories, and Szostak's ideas about the emergence of RNA replicators.
However, the huge number of parts and complex interactions involved in creating the simplest living organisms places the estimation of probability of origin of life in a whole other category of difficult, compared to the other factors.
At this time, fl is TOTALLY unknown, and so any use of the Drake Equation for computing a final result is likewise totally unknown.
mhack
Building a better ribosome since 1997
It's super novas, not old-burned out stars.
And remember that they are a rather local phenomenon, so metal enrichment of the next generation of stars is patchy.
Indeed, there are stars substantially older than Sol with similar metallicity. They are rarer and they haven't spawned alien civilizations that have prevented us from arising.
Why not? No-one knows.
"Belief" as defined by the dictionary basically means "faith". This is certainly different from "understanding". Individuals may "believe" that what the scientists say is true if they don't perform the experiments themselves, but the scientists who do perform the experiments have an understanding whether the results are consistent with the predictions.
This proves merely that if you are allowed to pick any numbers you please, and multiply them with eachother, you can arrive at any answer that you want to arrive at.
That's really all the Drake-equation shows.
That would explain "a long time ago, in a galaxy far, far away...".
I'm not saying it because I'm a optimist. But I think life is highly abundant wherever it can exist it will exist. I'd like to point out that for billions of years there was no multi-cellular life on earth, and once a few cells got stuck together it's only been a few hundred million to get to here. We could have, infact been here 3-3.1 billion years ago if conditions were right. So I'd place money on the upper bound, but it depends if we're talking sentient intelligence species you could have a philosophical conversation with or a genuine technological civilization such as our own.
So if there are between 5x10-7 and 10,000 civilizations in our galaxy, where are they? The answer I think will be interesting - we simply do not know what happens to intelligent species after they evolve. The problem is with the fallacy known as the fermi paradox is that there are far to many plausible reasons why intellegent species may rise and fall, or simply decide not to show up despite having plenty of time to do it.
I consider it vastly more likely that the majority of sentient creatures in the universe have no hands or similar useful appendages and therefore never acquire technology. I reason that planets with oceans (like our own right up to mega planets with water oceans 100s of km deep)would be vastly more abundant platforms for evolution of life in the universe than land area on earthlike planets.
If we could go out in a billion star ships and turn over every rock in the galaxy maybe we'd find most sentient life will be something like a whale or dolphin.
We seem to forget what wanders about on land contemplating financial markets and marvelling at smart phones, is only a vunerably small portion of the bio mass on this rock, and here the oceans are ruled by Cetaceans who in our own example have been here longer than us, and have had some of the highly developed brain structures they share with us millions of years longer, they used to populate hundreds of millions.. but we've eaten most of them). They'd probably persist after cataclysms that would wipe us out. (Octopii and squid are also relatively intellegent too, there's a hint that the format of a ET might be)
So with the majority of ET life being underwater there's little opportunity for tool making by hypothetical aquatic beings, let alone harnessing technologies we have done - which all largely stem from the ability to make fire and bootstrap from there. Consider that the majority of these oceans would be lidded by ice (like Europa) and these types of environments will vastly outnumber earth-like planets in that perfect habitable zone around the right kind of stable star.
So considering planets with habitable land area, in a stable orbit around a stable star, avoiding bombardment or supernova sterilization long enough for life to make the leap to multicellular and upwards, are a rarity - it becomes worse, there are still reasons why ETs may not show up.
Life could evolve at the bottom of a big gravity well -- a much larger planet with such an escape velocity that makes space travel difficult. The planet could have permanent cloud cover, thus the beings inhabiting it never see the sky and never wonder what's out there. They could also be very large like elephants, and therefore won't be inclined to be building flying machines. They could also have a geology absent of fossil fuels, no easy fuel for an industrial revolution. They may just refine a peaceful culture that's stable over longer periods of time and not particularly adventurous.
They may also not develop the right kind of intelligence. Or they may be pathologically self destructive. Our desire to explore and exploit is derived from our ancestors nomadic lifestyle. Without this background we may never have dreamed up the idea of exploring beyond our own world. So who's to stay an intelligent species would inevitably bother beaming signals out to space let alone traveling?
On earth, every single rock we look under, every tiny
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
Are any of them - you know - HOT? Will be able to - you know - have FUN with them? These are the important questions needing answers right now...
really ?
Read radical news here
Maybe we underestimate the difficulty of crossing 5-20 lightyears every trip.
I mean, we don't even dare to start a trip to Mars yet; and our first trip to mars isn't even planned to be for settling it or even a permanent base like we maintian on the poles, it is just for a quick visit. We need autonomic factories and mines before we can even think about settling.
Hey don't blame me, IANAB
NEVER! I am the Lizard King! reference
I know tobacco is bad for you, so I smoke weed with crack.