Are We Alone In the Universe? Not Likely, According To Math (cnet.com)

An anonymous reader writes: An equation, which calculates the probability of the evolution of other technological civilizations, has found that it's wildly unlikely we're the only time advanced society in the universe. Adam Frank from the University of Rochester and Woodruff Sullivan from the University of Washington base their new equation on the Drake equation, used for calculating the probability of extraterrestrial civilisation, written by astronomer and astrophysicist Frank Drake in 1961. The scientists also take into account Kepler, which suggests that one in five stars have planets in the habitable zone. Frank and Sullivan calculated that human civilisation is only unique if the odds of a civilisation developing on a habitable planet are less than one in 10 billion trillion. "One in 10 billion trillion is incredibly small. To me, this implies that other intelligent, technology producing species very likely have evolved before us," Frank said. Frank said: "Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet. But using our method we can tell exactly how low that probability would have to be for us to be the ONLY civilization the Universe has produced. We call that the pessimism line. If the actual probability is greater than the pessimism line, then a technological species and civilization has likely happened before."

Comments

It's wildly unlikely we should exist

[freak0fnature]

given how complex we are...

Re:It's wildly unlikely we should exist

[Dunbal]

it's almost as if someone intelligent designed us....

incoming shitstorm

Seriously, we're not that complex. A few billion years is an incredible amount of time.

Re:It's wildly unlikely we should exist

[khasim]

But the UNIVERSE is huge. With billions of galaxies. And each galaxy has billions of star systems.

The question isn't whether we are the only planet where life evolved.

The question is whether any other life will ever be able to contact us.

The universe could have a million planets with intelligent life. And not one of them within a million light years of another.

Re:It's wildly unlikely we should exist

[theIsovist]

We might not be that complex, but we're still outside of the norm. Which means that even though the total number of beings like us might be numerous, it's still rare. To quote Douglas Adams who does a much better job of describing this:

“It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.”

Re:It's wildly unlikely we should exist

[Dunbal]

How are we outside the norm? Given the size of the universe, the handful of planets we've managed to examine so far can't be considered anywhere near being a representative sample. Who are you to say what the "norm" is? I appreciate the Hitchhiker quote, btw. Just saying - the "norm" might not be what we think it is.

Re:It's wildly unlikely we should exist

[MightyMartian]

One may argue that we are outside the norm for life on Earth; although i'd argue that there are enough other species that show some degree of sentience; members of genus Corvus, the other great apes, cetaceans, and even elephants, that I'd argue that we are more the most extreme example of a phenomenon found in several lineages, in particular in mammals (though genus Corvus are birds). The differences are more degree. Obviously that matters, because there are no chimps building skyscrapers or writing posts on Slashdot, but it also means that our cognitive abilities are firmly entrenched in evolutionary processes.

There's no reason to imagine that if Earth alone can produce two or three lineages of animals capable of some degree of sentience that there aren't millions of worlds in the vastness of the Universe that haven't produced similar organisms.

Re:It's wildly unlikely we should exist

[SJHillman]

Don't confuse the Universe with the Observable Universe. The Observable Universe is not infinite. The Universe may well be.

Re:It's wildly unlikely we should exist

[SJHillman]

There's one significant flaw in that reasoning. If we assume there are infinite planets, and only a tiny subset of them are inhabited, that subset does not need to be finite... it can still be infinite.

Consider integers. There are an infinite number of integers. One subset of that is odd numbers. If we subtract an infinite set (odds) from an infinite set (integers), the remainder can still be an infinitely large set (even numbers).

Re:It's wildly unlikely we should exist

[Sparowl]

That's not mathematically sound. If there are infinite number of world, then saying that not everyone is inhabited does not reduce the number of world to a finite number. It could still easily be infinite number of world, with an infinite number of inhabited ones.

Infinity is a difficult to understand concept for many people.

Re:It's wildly unlikely we should exist

[MightyMartian]

Intelligence is one solution to the problem; a solution that has been used by a lot of species since the first nerve fibers joined together to form a primitive ganglion. But it's hardly the only solution. In sheer biomass, E. coli has all the multicellular animals with brains beat, because its solution to the problem of survival is to reproduce very frequently. In reality, that works really well, which is why most of the life on Earth is in fact prokaryotes. All the eukaryotes are just sort of an icing on the cake, and a rather thin frosting at that.

Re:It's wildly unlikely we should exist

[Muros]

there are no chimps building skyscrapers or writing posts on Slashdot

You must be new around here.

Re:It's wildly unlikely we should exist

[serviscope_minor]

It's also wildly unlikely that I got these numbers out of /dev/random (base64 encoded):

a2yIbR 06VMDu f3WkRu mCTMwT S/1sTr 5MC+JF VIAYQo El1/dj WPL+JL HNUZSZ 0yTnsd UDstFc SwIQcZRCTZ MXVO1o cqvrbG vn1TF4 qKhdL4 mBsdiI BxZ4Sx 9P+Pcj zto/bY w9+afI +JNUfu XpETQK 2k7dWFBSqC phnTUe y9cRsQ LfPeAX +sUA+n IB5xD7 fnJlF8 SwfMyE K3wuJb PfCKSc yjDkBk 8zXqnr AbDcwdVvMf GofKC4 fnbv6x j81Wyp ip3Zym Dva50x kRAFHB Z2PD+r e6PewB Jwg2NW rrSRf8 vKyRRe 1d4nTKRIYe NhFD2x mcudTw ybhJX/ BenFJD m+Z4JK xk86DT v71laB wywDf7 xhGVBh dLeILX pPDpoH OJV9jsziLY r6FpU1 5U0/0Q xRlv72 XYCbeY cUKvrS pkTgvp NqOhQi KBRxEc +tpS6D 31XcM/ skM9s1 t+gkTTQYpw FT6Q37 r5pdhq P/bENf Nfq4wA p17TnV +Iqz1Q FlmocM YQtp3l N7aopC t//jtL OkbO9r OdUMwq/Yak aySm9L U5IwSJ Lca1gs kUAgyh GNk099 eu9GgC d10kWL EMoX6D lA6bdY 7AYESp nA7hT6 ChZOraHk3+ a7sZDT GElTZI 4sSflA 1ccbmi B9V4HR BieFj4 G0F8qg Gy7ugw BP4DQ0 G8IyJ8 OZprIx 029GlmXibT rWQMgk 3D/EsS 9Jqu4m kcNDdB jij85G HXU/dr uG9eXD 73FtnX MoXBsq cjccXR oDhZxN DnubE+7vhS xR/Gxg L/FmN7 Q/hilg SBiZNw UeMz5M 1CLLag Mp+Lae TNRsbk YryRuv IFck/+ KO2yH8 y9GqQyK90c WoCTQF Yb04UQ OmPHCt ZELs2C HZaE/x 8uaUoO 7tBA0I Um57tZ RZ1gVK pSD4zN hRIPyJ I6efcIC1an JkQnuV 1vdtXr QDzXv3 8gLeK1 yGiBga KOJOBr aIjeBF S39M4L G3sZ2L wGutBe fVyWF2 Z7UOzh2yny IUQ/bS gt0fMM V1+GWE r1f+zh f5QKnL rDMIPi ENg10n SsRQ+E gl5ims 0gEvxc ZuNTgi vN9v6s1EgL wEAMJW IN4dJO fjanbL lro2fS CI4dwG UWqGV2 SOXH6o 8Gs0rM KaiNkb ny4GXQ ZzcBq2 QaJYgrnHM3 I4EhgD VEpPoU djY9hb kGuSDt Pth+9R xqqxxy 6NUlDk sHUiXh 8lq+B0 QLPVNt SaF6Wc BICSPupiCP n8QoEY ZKKK1X qN5qoB qkOtTt 77bbiH xqUC80 eOPdS0 RBsMNL e/AlKL NUmspv KjDzba bnPZtF9BH0 I9yTXr YjMn5K hSRjKD qy+SoL E8xT8Z ZgY1rA ==

The chance was in face 1 in 2^8000, or if you prefer 1 in 1.7E+2048. We could run this universe over many bilions of times and no one would get those numbers again, so treasure them!

So, as you can tell that event above is very unlikely. However, the chance of me getting 1000 numbers out of /dev/random is very close to 1. I'd expect it to fail very much under 1 in a billion times.

In other words, just because a specific event is unlikely (me getting those digits/this type of life evolving) doesn't mean that getting AN event from the class (e.g. some digits from /dev/random or some type of life evolving) is nearly so unlikely.

Re:It's wildly unlikely we should exist

[sinij]

given how complex we are...

Complexity != Quality, or every bloatware and spaghetti coder out there would have created true AI by now.

Re:It's wildly unlikely we should exist

[medv4380]

Douglas Adams logic is simply a fail. Just Substitute Worlds for Numbers, and inhabited worlds with Prime Numbers.

“It is known that there are an infinite number of Numbers... However, not every one of them is Prime. Therefore, there must be a finite number of Prime Numbers... From this it follows that the population of Prime Numbers is also zero, and that any Prime Number you may meet from time to time are merely the products of a deranged imagination."

The Truth is there is an Infinite Number of Prime Numbers in spite of there being space between them. The question really is whether or not the odds of intelligent life is comparable to Prime Number, or to the occurrence of a single solitary number. Also the 1 divided by Infinite is infinitesimal not nothing as Adams asserts assuming you're not a blaspheming finitist. And if you are a blasphemer 1 divided my infinite is nonsensical.

Re:It's wildly unlikely we should exist

[TFlan91]

We only think it's outside the norm because our ancestors either assimilated or killed of other species of intelligent life long before anything close to what we consider human civilization ever occurred.

Re:It's wildly unlikely we should exist

[DeathToBill]

One flaw? Every single sentence in that quote is either false or unknown. Let's review:

• It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. The universe is not infinite. It may be unbounded (ie have no edges), but that is different.
• However, not every one of them is inhabited. This one might be true. It is, as far as we know. It might be argued we don't know very much, though. Inhabited with what is not specified.

• Therefore, there must be a finite number of inhabited worlds. False, as you point out - supposing that the premises are true, the number of inhabited worlds may or may not be infinite.

• Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero.The first half is true-ish. Certainly the limit as x->infinity of y/x, for finite y, is zero. What relevance this has to the remainder of the sentence is not clear. If the number of inhabited worlds is finite, then so is their population and each populated world will have a finite, non-zero average population. If the number of inhabited worlds is infinite, then so is the total population.
• From this it follows that the population of the whole Universe is also zero False, since its premises are false. Even if the premises were true, infinity times an infinitesimal number is not zero.
• and that any people you may meet from time to time are merely the products of a deranged imagination. This depends rather on your personal situation.

Re:It's wildly unlikely we should exist

[zamboni1138]

Thanks for reminding me to go buy a Powerball ticket.

Re:It's wildly unlikely we should exist

[Jason Levine]

Even if we limit ourselves to the Observable Universe, there are billions of galaxies each with billions of stars. If even one hundredth of one percent of those stars had planets, one hundredth of one percent of those planets harbored life, and one hundredth of one percent of those planets with life had intelligent life, we'd be talking about millions of civilizations. We might be so far away from one another that the chances of finding each other approach zero, but there's a very good chance (probability-wise) that other intelligent life is out there.

Re:It's wildly unlikely we should exist

[ShanghaiBill]

It is also unlikely that we'll ever make contact with another intelligence in our own galaxy.

It is unlikely that we will make contact with a specific civilization, but there are 100 billion stars in the galaxy, so there may be millions of civilizations out there.

It is 100,000 light years across.

You don't have to go 100,000 ly in one jump. Even in our neighborhood, the stars are only a few ly apart. In much of the galaxy, they are much closer than that. If a civilization propagates through the galaxy at even 0.01c, that is just a blink on the time scale of geology or biological evolution.

Re:It's wildly unlikely we should exist

[drinkypoo]

Let me amend that. There are not a lot of chimps posting on /.

No, mostly they moderate.

Re:It's wildly unlikely we should exist

[Phoghat]

And the likelihood that most of those have intelligent being who are already extinct

"Habitable Zone"

[phishybongwaters]

That has always bugged me. Who are WE to determine that life has to be like US. Screw the habitable zone, there is ample life found on OUR planet that is found in areas considered inhabitable. Why assume life out there would be carbon based, breath, and require water? We're looking for life outside of this little snowglobe, but we've placed a mirror infront of the telescope. We'll miss extraterrestrial life because we were looking for ourselves the whole time.

Re:"Habitable Zone"

[Dunbal]

You make a good point. It recalls the argument whether a mayfly actually can perceive a tree as being alive, since the mayfly lives from a few minutes to two days at most, and trees can live hundreds or even thousands of years. But on the other hand - would we have any interest in "life-forms" or beings that have scales or life-spans so large that any perception, let alone communication, between us, is absolutely impossible. It's a bit anthropic but life pretty definitely has to fit within standards we define for us to consider it to be alive. Anything else is simply outside our scope. See? Relativity can apply to xenobiology too.

Re:"Habitable Zone"

[taiwanjohn]

Earth would not be in the habitable zone without plate tectonics. Venus would be in the habitable zone if it had about a zillion times less CO2 in its atmosphere. Mars would probably be in the habitable zone too, if it were bigger and had a magnetoshpere.

It's all relative.

Re:"Habitable Zone"

[thinkwaitfast]

Check out xenopsychology by Robert Freitas (a real phd scientist) and also the concept of Sentience quotient defined s

as the relationship between the information processing rate (bit/s) of each individual processing unit (neuron), the weight/size of a single unit and the total number of processing units (expressed as mass).

At present, human scientists are attempting to communicate outside our species to primates and cetaceans, and in a limited way to a few other vertebrates. This is inordinately difficult, and yet it represents a gap of at most a few SQ points. The farthest we can reach in our "communication" with vegetation is when we plant, water, or fertilize it, but it is evident that messages transmitted across an SQ gap of 10 points or more cannot be very meaningful. What, then, could an SQ +50 Superbeing possibly have to say to us?

Re:"Habitable Zone"

[ShanghaiBill]

Why assume life out there would be carbon based, breath, and require water?

Plenty of life doesn't "breathe", so nobody is assuming that. Early life on earth was almost certainly anaerobic. But carbon and water have some very useful properties, and they are both extremely common in the universe. So assuming that life is carbon based in a liquid water medium is reasonable.

Also, we are searching in extreme environments outside the habitable zone. For instance, we are planning missions to Europa which has far more liquid water than earth.

Re:"Habitable Zone"

[Krishnoid]

What, then, could an SQ +50 Superbeing possibly have to say to us?

Who's a good girl? Whoooo's a good girl?

Re:"Habitable Zone"

[serviscope_minor]

Who are WE to determine that life has to be like US.

Well, obviously that's silly, however...

Why assume life out there would be carbon based, breath, and require water?

Because we don't know any better. It's likely that carbon is important. There are several reasons for this. First, it forms stable, complex molecules over a wide range of temperatures. Silicon does to some extent, though the upper limit on the temperature is much lower. Boron also formes long complex molecules readily. There might be options with some metals too.

However abundance is also key. Boron is not formed in stellar nucleosynthesis un significant quantities unlike silicon and carbon, so it is very rare. This is a downside for life, since some non living process would have to concentrate it first.

The next problem is solvents. Likely solvents are hydrocarbons, ammonia, water, sulphuric acid and possibly liquid or supercritical gasses like nitrogen or hydrogen. We know those do exist out there in space. More exotic solvents may well depend on a large quantities of large molecules being formed (unlikely) or concentration of rare elements (also unlikely).

Those solvents will affect what chemistries are possible and what the base molecules are.

Now, the thing with carbon is that it comes in a variety of forms ready made. There's plenty of methane around the solar system, and the interaction with UV makes various other molecules too. However, silicon just doesn't seem to do that which puts it at a disadvantage. Likewise, CO2 is a nice gas which can spread itself around, unlike SiO2 which is rather more rooted to the ground.

So, while there might be non carbon forms of life, the other elements are at a severe disadvantage.

As for solvents, yeah I can see other ones could work. There's a few choices.

Re:"Habitable Zone"

[DigiShaman]

So, the Universe could be nothing more than a sub-atomic particle for yet another larger universe it sits in. In that larger Universe, our sub-atomic existence is in fact part of what makes up a carbon atom. Zoomed out, that carbon atom is bonded with an organic molecule! Zoomed out further still, it's part of a mass of extruded excrement laying on someone's lawn someplace; forced out by the most ugly dog imaginable; a very very very large dog I might add.

The origins of our existence might not be so glamorous after all.

Re:"Habitable Zone"

[MobileTatsu-NJG]

What I find funny about this discussion is that our whole mathematical proof that extra-terrestrial life exists basically boils down to: "There's lots of places to look." Which is fine until we get to Fermi's Paradox, which reels that back in. There is no math that can determine if we're alone in the universe until we actually meet any. At best all math can say is: "Here's how long it'll take to give up the search."

The best we can do is try to narrow down where we'd search. That's the point of the 'Habitable Zone', it should really be called the "Familiar-to-us Zone'.

Re:"Habitable Zone"

[AthanasiusKircher]

What I find funny about this discussion is that our whole mathematical proof that extra-terrestrial life exists basically boils down to: "There's lots of places to look." Which is fine until we get to Fermi's Paradox, which reels that back in.

Actually, I'd say the argument really boils down to the Principle of Mediocrity.

We assume that there's nothing too "special" about our place in the universe. And that seems to work well so far when we look at galactic structure or stars or solar systems -- as we gaze out into the universe, we find a lot of stuff that looks superficially like what we see around our "neck of the woods."

The problem is that most of those big structures are dependent on very basic physical principles -- how gravity works, how nuclear fusion works in stars, how much of various elements are present and relatively evenly distributed.

But life is pretty complicated. It could be if you make a "stew" of approximately the right mixture of stuff in the approximately right temperature and gravity conditions, life just self-organizes most of the time. Or, it could be that the "stew" and conditions were much more specific and the requirements are much more narrowly determined (enough so that life is pretty rare in the universe).

We simply can't know until we (1) observe life in other places, which will allow extrapolation and estimation of probabilities, or (2) manage to run our own "creation experiment" to evolve life ourselves in a lab, probably over millions of years -- in which case we can look at the conditions that seem to be required.

So, the ONLY reason for believing it's even worthwhile to look other places is the Principle of Mediocrity. But there's little reason to believe that the Principle of Mediocrity applies equally to patterns caused by really basic fundamental things like gravity and atomic structure vs. patterns caused by self-organizing complex life forms. Maybe it does. That'd be cool -- life everywhere in the universe. Maybe it doesn't, and we're pretty rare.

There's no "mathematical" argument to be made here at all, until we have more than one data point.

Mathturbation

[frenchgates]

This is just silly. The Drake equation has always been a joke. It's an extrapolated tautology that the chances for life on other planets are based on the chances for life on other planets.

Re:Mathturbation

[T.E.D.]

It was never meant to be a descriptive mathematical formula, like Bernouli's Equation. Its just a way to break questions about the amount of life in the universe down into manageable chunks that can be reasoned about. Complaining that its not a real equation is like a software engineer going up to a network engineer and telling them a "protocol stack" is a joke because its not a real design pattern. Perhaps you are technically right, but seriously, find more productive things to attack.

And two months ago, a completely different outcome

[tekrat]

What happened to the scientist that modeled the universe and concluded that not only are we alone in the universe, according to his model, even we shouldn't exist?

I remember commenting on that story, claiming it it was a near-mathematical impossibility for us to be alone in the universe, and his model was wrong. Of course, the usual naysayers came out of the woodwork, but now lo' and behold, here's another story that supports my assertion.

Of course, next week, we'll be back to being alone in the universe.....

Size of the Universe answers this question

[gurps_npc]

When you look up in a sky full of stars - all of which belong to the Milky Way Galaxy.... (at least 9,000), and about 4 other galaxies.

And know that with a common telescope we can detect both far more stars within our galaxy (over 100 billion) , AND a whole bunch of other galaxies...

And know that the galaxies form clusters - and cluster contains about 100+ galaxies (often 1000+)....

And know that there are thousands of clusters...

Basically, there are more stars than grains of sand on earth, than water molecules in a drop of water, than seconds in all of humanity's life span.

Yes there's other life out there. Now, whether it's intelligent, still alive, within a reasonable travel/speaking distance of us, that's another story.

Re:Size of the Universe answers this question

[myowntrueself]

When you look up in a sky full of stars - all of which belong to the Milky Way Galaxy.... (at least 9,000), and about 4 other galaxies.

And know that with a common telescope we can detect both far more stars within our galaxy (over 100 billion) , AND a whole bunch of other galaxies...

And know that the galaxies form clusters - and cluster contains about 100+ galaxies (often 1000+)....

And know that there are thousands of clusters...

Basically, there are more stars than grains of sand on earth, than water molecules in a drop of water, than seconds in all of humanity's life span.

Yes there's other life out there. Now, whether it's intelligent, still alive, within a reasonable travel/speaking distance of us, that's another story.

This is all great and stuff. But it isn't evidence of the existence of other life.

Only for all practical purposes

[NotDrWho]

Having company is meaningless if it's

Too far away to ever call
Too far away to ever visit
Living in a different time period

Re:And two months ago, a completely different outc

[pr0t0]

I think the quote from Contact's Ted Arroway sums it up the best:

I'd say if it is just us... seems like an awful waste of space.

Re:You Cannot Get Something From Nothing.

[RatBastard]

And none of those things have to do with evolution. You might want to spend some time figuring out what the hell you're arguing against in the first place.

Mental masturbation

[Dog-Cow]

The question of whether there is recognizable life outside our solar system is not a matter of statistics. Either there is life, or there isn't. The formula is entirely meaningless; either we (as a species) will encounter such life, or we won't. The likelihood is irrelevant.

Re:You Cannot Get Something From Nothing.

[Z00L00K]

Go study quantum mechanics and come back.

Lying headline

[Spazmania]

The headline is a lie. You can't project probabilities from a single known example. The math doesn't work that way.

Define Alone

[TomGreenhaw]

Given the vast distances and time that separates anything we would identify as "us" we already know that we are for all practical purposes alone.

Re:You Cannot Get Something From Nothing.

[MightyMartian]

I'm not equivocating, because most of what you refer to is either garbage or highly contested philosophical interpretations.

I'm sorry. You don't have a Prime mover to show me, and you cannot even demonstrate that one is necessary.

I don't need an alternative explanation. That isn't how it works. It's your job to come up with a testable verifiable and falsifiable test for your Prime Mover. That is your job, so produce the paper and the data that shows the Prime Mover exists. Don't give me speculative papers about a holographic universe and a bunch of religious mumbo jumbo, because you're right, I absolutely and completely reject anything that isn't real, verifiable evidence.