Radio Telescopes.  Credit: University of Washington

Extreme Life, SETI

A New Drake Equation? Other Life Not Likely to be Intelligent

13 May , 2009 by

Looking for signals from distant civilizations might be an effort in futility, according to scientists who met at Harvard University recently. The dominant view of astronomers at a symposium on the future of human life in the Universe seems to be that if other life is out there, it likely is dominated by microbes or other nonspeaking creatures.

Speakers reviewed how life on Earth arose and the many, sometimes improbable steps it took to create intelligence here. Radio astronomer Gerrit Verschuur said he believes that though there is very likely life out there — perhaps a lot of it — it is very unlikely to be both intelligent and able to communicate with us.

Verschuur presented his take on the Drake equation, formulated by astronomer Frank Drake in 1960, that provides a means for calculating the number of intelligent civilizations that it is possible for humans to make contact with.

The equation relates those chances to the rate of star and habitable planet formation. It includes the rate at which life arises on such planets and develops intelligence, technology, and interplanetary communication skills. Finally, it factors in the lifetime of such a civilization.

Using Drake’s equation, Verschuur calculated there may be just one other technological civilization capable of communicating with humans in the whole group of galaxies that include our Milky Way — a vanishingly small number that may explain why 30 years of scanning the skies for signs of intelligent life has come up empty.

“I’m not very optimistic,” Verschuur said.

Dimitar Sasselov, professor of astrophysics at Harvard and director of the Harvard Origins of Life Initiative, agreed with Verschuur that life is probably common in the universe. He said that he believes life is a natural “planetary phenomenon” that occurs easily on planets with the right conditions.

As for intelligent life, give it time, he said. Though it may be hard to think of it this way, at roughly 14 billion years old, the universe is quite young, he said. The heavy elements that make up planets like Earth were not available in the early universe; instead, they are formed by the stars. Enough of these materials were available to begin forming rocky planets like Earth just 7 billion or 8 billion years ago. When one considers that it took nearly 4 billion years for intelligent life to evolve on Earth, it would perhaps not be surprising if intelligence is still rare.

“It takes a long time to do this,” Sasselov said. “It may be that we are the first generation in this galaxy.”

Several speakers at the event hailed the March launch of NASA’s Kepler space telescope, which is dedicated to the search for Earth-like planets orbiting other stars. Several Harvard-Smithsonian Center for Astrophysics faculty members, including Sasselov, are investigators on the telescope mission.

Andrew Knoll describes the beginnings of life on Earth. Photograph by Stephanie Mitchell/Harvard News Office

Andrew Knoll describes the beginnings of life on Earth. Photograph by Stephanie Mitchell/Harvard News Office


Sasselov said he expects Kepler to quickly add to the 350 planets already found orbiting other stars. By the end of the summer, he said, it may have found more than a dozen “super Earths” or planets from Earth-size to just over twice Earth’s size that Sasselov expects would have the stability and conditions that would allow life to develop.

If life did develop elsewhere, Andrew Knoll, the Fisher Professor of Natural History, used the lessons of planet Earth to give an idea of what it might take to develop intelligence. Of the three major groupings of life: bacteria, archaea, and eukaryotes, only the eukaryotes developed complex life. And even among the myriad kinds of eukaryotes, complex life arose in just a few places: animals, plants, fungi, and red and brown algae. Knoll said he believes that the rise of mobility, oxygen levels, and predation, together with its need for sophisticated sensory systems, coordinated activity, and a brain, provided the first steps toward intelligence.

It has only been during the past century — a tiny fraction of Earth’s history — that humans have had the technological capacity to communicate off Earth, Knoll said. And, though Kepler may advance the search for Earth-like planets, it won’t tell us whether there’s life there, or whether there has been life there in the past.

Other speakers included J. Craig Venter, Freeman Dyson, Peter Ward, Andy Knoll, Maria Zuber, David Charbonneau, Juan Enriquez, and David Aguilar.

Source: PhysOrg

By  -        
Nancy Atkinson is currently Universe Today's Contributing Editor. Previously she served as UT's Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is also a NASA/JPL Solar System Ambassador.


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Nexus
Member
May 13, 2009 3:35 PM

I’ve read a lot of science fiction featuring ancient and highly advanced alien races, like Arthur C. Clarke’s 2001. The thought that we might be among the oldest civilizations is an interesting one.

Kevin F.
Member
Kevin F.
May 13, 2009 5:05 PM

Yeah, though it’s depressing that we might be “alone” in our large corner of the galaxy, it would still be neat if future races discovered our achievements long after we died out and called us “The Old Ones”.

yanluz86
Member
May 13, 2009 5:13 PM

Very interesting and puts a few new thoughts out there that the milky way may only have 1 or 2 intelligent civilizations.

I hope not of course. I hope there is more civilizations around.

wayno@oz
Member
[email protected]
May 13, 2009 5:16 PM
I think after 30 years of scanning the skies we can safely assume we are one of the first intelligent civilizations in our galaxy. It would help explain why we have yet to recieve a signal from the stars.(excluding the WOW signal, i believe this may have been a passing probe from another civilization, unaware of our position in the galaxy) I dont believe we are the only intelligent civilization in the galaxy, it may be that we are the first to communicate with radio waves and it could another thousand years before another intelligence discovers those signal’s, if at all. It sucks, i know, and the thought that only we are the masters of our destiny is… Read more »
wayno@oz
Member
[email protected]
May 13, 2009 5:21 PM

Sorry for the personal theory on the WOW signal, i had already frogtton the new rules. My deepest apoligies. Wayno.

Ringman
Member
May 13, 2009 5:45 PM

when you think about it though, we’ve only been listening for these signals for the last 30 years, that means that the furthest radio signal we could receive now would be only 30 light years away, that’s not very far compared to the size milky way

Damien
Member
Damien
May 13, 2009 5:53 PM
I’ve had the same opinion for many years – primitive life is likely prolific, but technologically intelligent life would be extremely rare, if it exists. The reasons are simple. Base chemicals that life depends on are relatively common. All you need is the right set of conditions including energy inputs and you could come up with single celled life quite readily. Earth was perfectly happy with that arrangement for about 4 billion years – that’s almost 1/3 the age of the universe! That complex multicellular life then evolved and that much later humans came on the scene is certainly not a given, far from it in fact. Even modern humans need not have evolved advanced technology – look… Read more »
Dominion
Member
May 13, 2009 6:13 PM

I feel that if there is an intelligent race out there among the stars, they are probably avoiding us. I wouldn’t come here if I was an alien. Wars everywhere and landfills piling up. We must look like a bunch of unsupervised preschoolers to them.

Silver Thread
Member
Silver Thread
May 13, 2009 7:12 PM

Agreed Dominion.

More over, *if* we do stand at the apex of technological evolution in our corner of the galaxy then it becomes even more critical for us to get out among the stars as a race. What a great tragedy it would be to have all the splendor and marvel that lies within the universe go unappreciated. It’s majesty vastly beyond the understanding of those creatures, less self aware. All the beauty and magnificence born of our own species to simply fall into the dark eternal silence of space and time. Whether our origin is mundane or divine it is a blessing and we are the lucky fated to be alive.

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 13, 2009 7:19 PM
I wrote a book last year, “Can Star Systems be Explored? — The physics of starprobes.” One chapter I devote to some astromechanics, chaos and statistics to estimate based on current data how many star systems would maintain a 1AU terrestrial planet in a stable orbit. I found that out of our whole galaxy about 1-10 thousand G-class stars might support an analogue to Earth. On such planets maybe life could emerge and evolve. Interestingly there should be several of these visible within the local Persius arm within a few thousand light years. We should be able to detect them. Kepler? Given that only 10^5 years out of 10^9 years of Earth’s has involved us humans, we might… Read more »
BHR
Member
BHR
May 13, 2009 7:40 PM

My personal theorie is there milions, maybe bilions, maybe much more, inteligent life in the universe. Even in our milk way, this number is big.

Astrofiend
Member
Astrofiend
May 13, 2009 10:46 PM
# [email protected] Says: May 13th, 2009 at 5:21 pm “Sorry for the personal theory on the WOW signal, i had already frogtton the new rules. My deepest apoligies. Wayno.” Look, the personal theory thing was put in place because people were PUSHING their complex alternate scientific theories in a blog comment space that is clearly not the correct forum for such things. That is a far cry from simply stating “I reckon such-and-such might be the case”, and admitting it is sheer light-hearted/good-natured/fun speculation. This is not a USSR communist thought suppression blog – you can express personal feelings on an issue or engage in some pragmatic speculation – just don’t write off other people’s or mainstream scientific… Read more »
tacitus
Member
May 13, 2009 11:13 PM
If intelligent life is very rare, then we may need to look outside the Milky Way for signals from extraterrestrial civilizations. Obviously, communicating between galaxies is inordinately more difficult than interstellar communication given the vast distances (millions of light years) and times involved. The amount of energy alone required for sending a signal that far is mind-boggling. But… If intelligent life is really so rare that only one or two civilizations per galaxy rise to spread out through the stars, then eventually those civilizations are likely to want to find out if they are alone in the universe. Once you have conquered your own galaxy, what else is there left to do but reach out to others who… Read more »
reciprocum
Member
reciprocum
May 14, 2009 12:19 AM
If technological evolution is exponential in nature and travel/comunication time is linear (even if you know how to travel at a significant fraction of the speed of light), then at a point evolution (of an inteligent species) will become so fast that, by the time an answer to a signal/question arrives the sender will no longer be interested in it, or will have already found (simulated ?) the answer by itself. Imagine technology in Earth a mere 1.000 years from know (a mere 10 generations away) will ANY question that we can pose today still be unanswered ? And that would be if we as a species learn how to stay focused on a multi-generation project. Just keeping… Read more »
lookas
Member
lookas
May 14, 2009 2:41 AM

There’s no evidence that biological evolution point straight into an intelligent being. Only one out of millions of different species that have populated the earth has evolved in an intelligent being.

damian
Member
May 14, 2009 3:35 AM
I find it ironic that Sentience has to be defined in terms of biology or technology as we understand it. When thinking of (alien) sentience or intelligence we really do have to (step) out of our own self image and also out of our limited perception of time. (ok; a hypothetical: please dont flame me What if the planet and indeed our sun were the products of a ancient race? The original generation ship perhaps. The question is, how would we recognize this as being the work of an intelligence by our present standard? And if there is a pilot for our solar system then our limited lifespan prevents us from communicating with it. We just call it… Read more »
Kevin F.
Member
Kevin F.
May 14, 2009 5:07 AM

I feel that if there is an intelligent race out there among the stars, they are probably avoiding us. I wouldn’t come here if I was an alien. Wars everywhere and landfills piling up. We must look like a bunch of unsupervised preschoolers to them.

That might not be the case. A diverse ecosystem so far as we’re aware requires organisms to eat other organisms. By extension of that violence is bound to crop up in the prevailing intelligent race – in some way. I don’t think an alien race would be necessarily offended by the things here on earth, just a little uncomfortable, like when you’re visiting neighbors who argue a lot.

Feenixx
Member
May 14, 2009 5:35 AM

I reckon the significance of the Drake Equation is highly over-rated, and that the equation means little more than nothing. It has some value as a teaching tool, to demonstrate what happens if you juggle probabilities across huge numbers.

I speculate about the abundance of exo-creatures and weeds, and their potential intelligence (or the absence of it) and edibility – and what they might look like. I also enjoy reading other speculations, I think about them, agree or disagree…. but I tend to leave the Drake Equation out of my conjectures and focus on other factors I have learned about, and continue to learn.

mosxu
Member
mosxu
May 14, 2009 5:36 AM

It looks like depression got the scientists as well.

Humankind only has about 100 years of technology and the universe is about 14 billion years old.

Imagine only the humankind in 1000 years from now or one million years not a billion and realize that we only start to understand things.

This why I think that some civilization will not talk to us yet because we are not that intelligent and besides that how much can we achieve in such a short life.

If the man would live at least 1000 years it will make a huge difference.

One day we will hear from out of stars!

Richard Kirk
Member
Richard Kirk
May 14, 2009 5:49 AM
The trouble with all Drake’s equation type stuff is that we are multiplying together a lot of very uncertain numbers to get a product that tells us either nowhere in inhabited and we’re only dreaming it, or everywhere it inhabited twice. However, using the one example we have… There is some evidence for signs of life at the end of the Hadean epoch, about 4 billion years ago, when the earth’s surface was barely solid and the skies were still raining rocks. The fact that it kicked off so quickly suggests that it isn’t insanely unlikely. These life forms were small and living slowly, and the earth was big. It took a long time before they were living… Read more »
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