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NASA's Kepler Mission Rewrites Drake's Equation --"Humans Not the First Technological Civilization in the Universe" (2016's Most Popular)

 

Backgrounds-space-background-planet-scifi-planets-desktop-ringed

 

"The question of whether advanced civilizations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation," said Adam Frank, professor of physics and astronomy at the University of Rochester. "We've known for a long time approximately how many stars exist. We didn't know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilizations might last before becoming extinct."

As Frank puts it "We don't even know if it's possible to have a high-tech civilization that lasts more than a few centuries." With Frank and Sullivan's new result, scientists can begin using everything they know about planets and climate to begin modeling the interactions of an energy-intensive species with their home world knowing that a large sample of such cases has already existed in the cosmos.

"Our results imply that our biological, and cultural evolution has not been unique and has probably happened many times before. The other cases are likely to include many energy intensive civilizations dealing with crises on their planets as their civilizations grow. That means we can begin exploring the problem using simulations to get a sense of what leads to long lived civilizations and what doesn't."

A new study shows that the recent discoveries of exoplanets combined with a broader approach to the question makes it possible to assign a new empirically valid probability to whether any other advanced technological civilizations have ever existed. And it shows that unless the odds of advanced life evolving on a habitable planet are astonishingly low, then human kind is not the universe's first technological, or advanced, civilization.

 

Cyber-space-nepal

 

The paper, published in Astrobiology, also shows for the first time just what "pessimism" or "optimism" mean when it comes to estimating the likelihood of advanced extraterrestrial life.

"Thanks to NASA's Kepler satellite and other searches, we now know that roughly one-fifth of stars have planets in 'habitable zones,' where temperatures could support life as we know it. So one of the three big uncertainties has now been constrained."

 

Drake-kepler

 

Frank said that Drake's third big question--how long civilizations might survive--is still completely unknown. "The fact that humans have had rudimentary technology for roughly ten thousand years doesn't really tell us if other societies would last that long or perhaps much longer," he explained.

The illustration of the Drake equation and the Frank equation is shown below. In 1961, astrophysicist Frank Drake developed an equation to estimate the number of advanced civilizations likely to exist in the Milky Way galaxy.

The Drake equation (top row) has proven to be a durable framework for research, and space technology has advanced scientists' knowledge of several variables. But it is impossible to do anything more than guess at variables such as L, the probably longevity of other advanced civilizations.

In their new research, Frank and Woodruff Sullivan offer a new equation (bottom row) to address a slightly different question: What is the number of advanced civilizations likely to have developed over the history of the observable universe? Frank and Sullivan's equation draws on Drake's, but eliminates the need for L.

 

A-tale-of-two-equations-696x327

 

"Rather than asking how many civilizations may exist now, we ask 'Are we the only technological species that has ever arisen?': said Sullivan. "This shifted focus eliminates the uncertainty of the civilization lifetime question and allows us to address what we call the 'cosmic archaeological question' -- how often in the history of the universe has life evolved to an advanced state?"

That still leaves huge uncertainties in calculating the probability for advanced life to evolve on habitable planets. It's here that Frank and Sullivan flip the question around. Rather than guessing at the odds of advanced life developing, they calculate the odds against it occurring in order for humanity to be the only advanced civilization in the entire history of the observable universe.

With that, Frank and Sullivan then calculated the line between a Universe where humanity has been the sole experiment in civilization and one where others have come before us.

"Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet," says Frank. 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."

Using this approach, Frank and Sullivan calculate how unlikely advanced life must be if there has never been another example among the universe's twenty billion trillion stars, or even among our own Milky Way galaxy's hundred billion.

The result? By applying the new exoplanet data to the Universe as a whole, Frank and Sullivan find that human civilization is likely to be unique in the cosmos only if the odds of a civilization developing on a habitable planet are less than about one in 10 billion trillion, or one part in 10 to the 22th power.

"One in 10 billion trillion is incredibly small," says Frank "To me, this implies that other intelligent, technology producing species very likely have evolved before us. Think of it this way. Before our result you'd be considered a pessimist if you imagined the probability of evolving a civilization on a habitable planet were, say, one in a trillion. But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about a 10 billion other times over cosmic history!"

For smaller volumes the numbers are less extreme. For example, another technological species likely has evolved on a habitable planet in our own Milky Way galaxy if the odds against it evolving on any one habitable planet are better than one chance in 60 billion.

But if those numbers seem to give ammunition to the "optimists" about the existence of alien civilizations, Sullivan points out that the full Drake equation -- which calculates the odds that other civilizations are around today -- may give solace to the pessimists.

"The universe is more than 13 billion years old," said Sullivan. "That means that even if there have been a thousand civilizations in our own galaxy, if they live only as long as we have been around -- roughly ten thousand years -- then all of them are likely already extinct. And others won't evolve until we are long gone. For us to have much chance of success in finding another "contemporary" active technological civilization, on average they must last much longer than our present lifetime."

"Given the vast distances between stars and the fixed speed of light we might never really be able to have a conversation with another civilization anyway," said Frank. "If they were 50,000 light years away then every exchange would take 100,000 years to go back and forth."

But, as Frank and Sullivan point out, even if there aren't other civilizations in our galaxy to communicate with now, the new result still has a profound scientific and philosophical importance. "From a fundamental perspective the question is 'has it ever happened anywhere before?'" said Frank. "And it is astonishingly likely that we are not the only time and place that an advance civilization has evolved."

According to Frank and Sullivan their result has a practical application as well. As humanity faces its crisis in sustainability and climate change we can wonder if other civilization-building species on other planets have gone through a similar bottleneck and made it to the other side.


The Daily Galaxy via University of Rochester

Image credits: top of page forwallpaper.com; NASA/Kepler Mission, U of Rochester; Frank Drake photo, SETI Institute

Comments

It would be interesting to map out the dimensions of "average lifespan of a civilization" against "average time to be visible to neighboring civilization" and draw maps for all values of "probability of a civilization to evolve on a habitable planet". There must be some cutoff, a minimum probability for two civilizations to evolve _and_ surviving long enough to being seen by each other. That should be much higher than the pessimistic value, but gives more insight on why we haven't seen anyone yet.

Until there is any empirical evidence of any other advanced civilizations, this is an argument based on faith. Heck, there really should be signs of advanced civilizations all around us right now.

@ T. Webb no in fact most of the drake equation is based on observation and probabilities based on known facts so its not just faith. True that we cannot even for sure give the drake equation a true number more so probabilities. Beyond that even we have no idea of the possible ways a advanced technological species might be able to hide there presence from our lower technology. We are just now learning about the quantum world which puzzled even Einstein. Math can in fact transcend faith altogether or enhance it or destroy it. Its our catalyst to understanding reality.

@ Andreas our advances in artificial intelligence should help us there, it's actually an old idea. Instead of searching the vast numbers of galaxies yourself, send spaceships controlled by Ai. There is an old Disney movie called The Flight of the Navigator in which a young boy encounters such an alien device studying Earth. Makes more sense than sending a biological being, a machine can simply warp threw space all it likes i would imagine if built correctly, it would be impervious to everything that would kill us in space.

Not necessarily 100,000 years. Contact might find us and they'll have better cellular.

An analog to the Drake Equation was this question on the entrance exam for graduate studies in physics at Chicago: "Estimate the number of piano tuners in Chicago."

@Matthew I was going for the easier assumption that the signal of a civilizations existence will propagate with the speed of light.

I have my own insight to this question, I believe civilizations die out because of internal fighting, alienation, and social-economical collapse from too many people, with too many cultures and too many different ethnic groups all fighting for control, money, and not sharing a common culture, language, and heritage, ensures that those civilizations don't survive and eventual return to a preindustrial state, where they then go extinct due to some natural disaster.

Matthew - "no in fact most of the drake equation is based on observation and probabilities based on known facts so its not just faith"

N=R*.fp.ne.fl.fi.fc.L

R* = average rate of star formation - reasonable estimate
fp = fraction of formed stars that have planets - getting there
ne = average # planets per star that can potentially support life - unknown
fl = fraction of ne that actually develop life - unknown
fi = fraction of fl on which intelligent, civilized life has developed - unknown
fc = fraction of fc that have developed detectable communications - unknown
L = the length of time over which fc release detectable signals - unknown

Two of seven is not most.

1928, Carl Stormer near Oslo...

La scienza umana ( a quanto pare) sembra esser vittima di se stessa.
Quanta intelligenza ed energie, sprecate per mettere in dubbio le regole procedurali che cattedra ( e cattedratici) si sono dati. Sapendo che in natura, non si riesce a formare neanche un triangolo senza un apporto esterno (ed intelligente), cosa direbbe ( o darebbe) l' equazione di Drake sulle possibilità che il DNA umano ( che Darwin non conosceva) , + l' RNA, si siano formati da soli ?
Copernico e Galileo, con l' empiricità dell' osservazione, ci hanno aiutati ad evolvere il pensiero e lo stato di cielo e cosmo, ma purtroppo, 600 anni dopo, non si riesce a riadottare la base scientifica per non avere il coraggio di dire ai negazionisti (militari e politici), che sarebbe ora di smetterla di prendere in giro una intera umanità. Speriamo che il "nuovo inquilino" di fresco arrivato al potere, che sbandiera ai quattro venti di "voler cambiare lo stato delle cose" riesca ( e voglia) trattare i propri simili con più dignità dei predecessori, e faccia sapere quanto finora è stato (incredibilmente) negato, a fronte di tutte le ( sia pur empiriche) evidenze esistenti, e liberare le cattedratiche intelligenze dai nocumenti (eretici) alla carriera.
TM

"We've known for a long time approximately how many stars exist. We
didn't know how many of those stars had planets that could potentially
harbor life." Is a very bold statement, considering that several new
galaxies have been found increasing the star count by billions... Also
you still don't know how many of those stars have planets that could
potentially harbor life.

"Thanks to NASA's Kepler satellite and other searches, we now know
that roughly one-fifth of stars have planets in 'habitable zones,'
where temperatures could support life as we know it. So one of the
three big uncertainties has now been constrained." No you don't, you
have what can be called a very tiny sampling from a very tiny area,
that sample is limited so the conclusion that you have is limited,
even though Adam Frank, professor of physics and astronomy at the
University of Rochester I am sure would disagree with it. As I said a
very limited sample from a very limited area. Would these numbers
change as you approached the center of galaxies, perhaps it would
change as you got farther away, and your conclusion of 1/5th would be
totally off. This is just bad science.

"A new study shows that the recent discoveries of exoplanets combined
with a broader approach to the question makes it possible to assign a
new empirically valid probability to whether any other advanced
technological civilizations have ever existed. And it shows that
unless the odds of advanced life evolving on a habitable planet are
astonishingly low, then human kind is not the universe's first
technological, or advanced, civilization." What studies are these?
What broader approach? How can a broader approach assign a new
empirically valid probability to anything whatsoever?

"The fact that humans have had rudimentary technology for roughly ten
thousand years." Again where do you get this crap from? Just because
the human species has had the ability to do certain things does not
mean we were capable of destroying the planet or the ecosystem. This
tech that is said that we have had for 10,000 years is comparable to
monkeys using sticks to dig grubs out of trees. Global warming may
have begun in the 18 or 19 century but with a very very very limited
exposure. It was not until the later half of the 20th that things
started getting bad. In fact you can almost localize it to a specific
decade when it began in earnest. That would be world war 2. So no,
humans have NOT had rudimentary technology for roughly ten thousand
years.

Sorry I will not even read the rest of this article, it is horrible

You deleted my comment the first time, what are you so scared of?

Seems to me they delete a lot of stuff except the crazy comments the wing-nuts send in!

What I've seen is comments deleted that point out that scientists are after all human, not paragons.

We don't have civilisation yet do we? I think we lost the plot when we settled down to farm and became dominated by male territorial-ism.

Yes Sapa, we have civilization. What you think doesn't represent what happened. Territorialism was practiced long, long before civilizations sprung up, being part and parcel to most complex animal behavior.

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