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

[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

[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]

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

[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

[khasim]

Sure, but it is unlikely we will ever make contact with life outside our own galaxy.

It is also unlikely that we'll ever make contact with another intelligence in our own galaxy. It is 100,000 light years across.

Then comes the issues of whether:
1. They'd have died out before they could reach us.
2. We die out before they've gotten past the "bang the rocks together" stage.

So many things have to happen in just the right order at just the right time. Look at our evolution for an example (the only one we have).

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

[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.

"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"

[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.

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.