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

"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"

[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"

[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: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.

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: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: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.

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

[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

[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

[drinkypoo]

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

No, mostly they moderate.