From the UNIVERSITY OF ROCHESTER:
Are humans unique and alone in the vast universe? This question– summed up in the famous Drake equation — has for a half-century been one of the most intractable and uncertain in science.
But a new paper 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.
The paper, to be 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.
“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 and co-author of the paper. “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.”
“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.”
Frank said that the 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.
But Frank and his coauthor, Woodruff Sullivan of the astronomy department and astrobiology program at the University of Washington, found they could eliminate that term altogether by simply expanding the question.
“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 ten 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’s 2 x 10 to the 22nd power stars, 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 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 20,000 light years away then every exchange would take 40,000 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. Our result is the first time anyone has been able to set any empirical answer for that question 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. 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 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 their feedbacks onto 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.”
Frank and Sullivan’s argument hinges upon the recent discovery of how many planets exist and how many of those lie in what scientists call the “habitable zone” — planets in which liquid water, and therefore life, could exist. This allows Frank and Sullivan to define a number they call Nast. Nast is the product of N*, the total number of stars; fp, the fraction of those stars that form planets; and np, the average number of those planets in the habitable zones of their stars.
They then set out what they call the “Archaelogical-form” of the Drake equation, which defines A as the “number of technological species that have ever formed over the history of the observable Universe.”
Their equation, A=Nast*fbt, describes A as the product of Nast – the number of habitable planets in a given volume of the Universe – multiplied by fbt – the likelihood of a technological species arising on one of these planets. The volume considered could be, for example, the entire Universe, or just our Galaxy.
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I personally have no doubt, zero, that there are many advanced species, like us or more so, in our own galaxy, not to mention the other galaxies. Some comments/minds say there is no evidence, some say we will never know. There is evidence, look at some of the french documents released on u. f. o. s. Even if this and the many other signs are not acceptable to those minds, it cannot be asserted that there is no evidence. Likewise, to say we will never know, is equally unknown.
If you want to find the evidence, it is all over the internet, with huge government involvement and the secrecy that requires and entails. The evidence: accounts, personal disclosures from the top people in the military, even the prime minister of Canada back a few years, I could go on. It is there, beyond all reasonable doubt. There is a type of phobia against believing, an irrational attitude that somewhat resembles those who refuse to believe CO2 from humans is an insignificant GHG
OK, let’s take this as a serious comment and not some subtle form of satire.
There are over 3 billion operational digital cameras on this planet. There were scores of videos of the Chelyabinsk meteor.
To date, not a single video or still picture, not a single one, proves the existence of intelligent extraterrestrial life. Or ghosts. Or Bigfoot. Or the Loch Ness monster. Get real.
Since there is no evidence for UFOs, UFOs can’t be used as evidence for anything.
When one looks at the chemicals of the universe, the anomalous behaviour of water, lightening etc and the way our climate is thermostatically controlled by the oceans and the water cycle. One would think earth like planets would be common. It would also be likely that if life was spontaneously created and evolved on earth it would happen all over the universe. We are yet babes in the woods as far as science and technology are concerned.
Science has not only been wrong in the past but very wrong, the speed of light may prove in the future to be not a barrier. The simple fact that so much information and sightings of UFO,s is extant and even tapestries from centuries ago feature then, would indicate that we are not alone,so some-one is travelling at a reasonable clip in space.
If current cosmological theories are right, the chain of events that led to the existence of the Earth that we know is long, convoluted, and not all that likely.
I dont know if Drake’s formula includes the radius of the candidate planet? If not, it should, because the forms of life that can develop on any planet are constrained by its force of gravity: photosynthetic organisms will compete for starlight, just as trees do on Earth and transport of water from roots to top will be constrained by gravity. So “plant” height must therefore depend on planet radius.. Same for consumer organisms that must move to obtain energy. Elephants would not be possible on a planet much larger than Earth. I’ll bet that to pass through the tool-maker, problem-solver stage the organisms that could produce a civilisation would be similarly constrained to a limited range of gravitational force. So some predictions about the type of higher organisms possible on any planet ay be derived from its size.
I am glad that for that trillionth status because I am a living spec in a vast universe and that there is a God who cares about me.
Descendants of an ancient the ‘clay hypothesis’ civilisation arrive from England to good ol’ U S of A
The article makes the assertion “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”.
The Drake equation relies on 7 components for which there is no scientific basis: A, Ne, fe, fi, fbt, fc and L. Assigning a value of anything to those components is complete arbitrary and unscientific. Belief in the predictive value of the “Drake Equation” is equivalent to having a belief in the existence in god. You are entitled to your opinon but both have no basis in fact.
When we finally begin to discover life on other planets, and discover other previous or existing civilizations we can then assign actual values that can transform “belief” in the Drake Equation to something actually scientific.
Having a planet in the inhabitable zone is only one factor in regards to developing an intelligent species.
For example, if the planet gets whacked by a meteor every couple of million years, it has very little chance of developing complex, much less intelligent life.
To protect that planet against meteors/comets, you need a planet like Jupiter, about where Jupiter is.
To prevent your Jupiter like planet from slowly spiraling in and destroying all the inner system planets, you also need a planet like Saturn, about where Saturn is.
If you solar system orbits too close to the center of the galaxy, it’s likely to be sterilized every few million years by nearby super nova.
Having a large moon helps to stabilize the axis of rotation in regards to the plane of the orbit. This gives a stable climate so that life can develop.
Having an large core is necessary in order to maintain a magnetic field so that the solar wind does not rip away the atmosphere before complex life has a chance to develop.
Interesting thoughts Mark.
But I don’t see why Jupiter should spiraling in without Saturn. Can you please explain why you think that would happen?
/Jan
I don’t completely understand all of the astromechanics myself all that well, but I’ll try to explain it as best I can.
Due to interactions with dust and small bodies, planets will tend to spiral in towards their sun once formed.
The inner planets have less of a problem with this because once the star lights, the solar wind helps to clear the dust out of the inner system.
Because of this dust, Jupiter would have continued to spiral in, until in encroached on the inner solar system. The result of this encroachment would have been the planets of the inner solar system being either captureded by Jupiter or kicked out of the solar system.
Saturn, once it formed, also began to spiral in towards the inner solar system.
At some point during that mutual spiraling, Jupiter and Saturn hit a point where Jupiter orbited the sun precisely 3 times, for every 2 orbits of Saturn. This caused an interaction between Saturn and Jupiter whereby Jupiter stole momentum from Saturn, this raised the orbit of Jupiter enough so that it was in an orbit that had already been cleared of dust, thus ending it’s inward spiral. Saturn also dropped into an orbit that was free of dust.
As to the outer planets, I don’t remember the full explanation regarding how they got stable orbits. It had something to do with much less dust out there to begin with as well as Jupiter and Saturn already clearing much of what dust did exist.
A couple of other factors. The current best theory regarding the origin of the Moon is that a planet about the size of Mars, that formed in almost the same orbit as the Earth (which explains why isotopically, the moon is almost identical to the earth) collided with the earth tangentially. The actual range of collision angles is fairly small. Too shallow, and the remains of the second planet would have been going too fast for the earth’s gravity to capture any of it. Too direct a hit and all of the debris would have been captured by the earth, leaving nothing to form a moon.
The angle of collision was such that much of the crust from the two bodies was thrown into orbit around the main body, while the core of the two bodies merged. This gave the earth both a thin crust and a large core compared to the other inner planets.
The large core was better at generating and retaining heat, so the earth has a powerful magnetic field that has survived to the present (Mar’s died away millions of years ago.) This magnetic field protects life on earth from radiation, as well as protecting the atmosphere from being striped away by the solar wind.
The thin crust made plate tectonics possible, the result of which was an ocean world with continents, instead of just an ocean world. Without plate tectonics, the continents would have eroded away long ago.
During it’s molten phase, most of the heavy elements sank to the earth’s core, leaving the crust poor in metals. Most of the metals we mine were deposited in the crust by what astronomers call the late heavy bombardment. The gravitational dance between Jupiter and Saturn disturbed much of the solar system. In fact Uranus and Neptune actually switched places during this period. One result of this disturbance was many comets and asteroids plunging into the inner solar system. These projectiles formed the late heavy bombardment. These comets also brought much of the water that covers the earth today. Most of the material that made up the early earth was dry, because the heat of the early sun dried them out.
Life exists in every nook and cranny of Earth.
Therefore life is natural.
Life is not contrary to the “plan”.
There will be life EVERYWHERE conditions such as those on Earth exist.
Why wouldn’t life elsewhere behave exactly as life behaves on Earth?
One should make decisions based on observations, instead of overwrought conjecture.
Simplify, Man, simplfy.
It’s quite possible that microbial life is common in the galaxy.
More complex than that? Much less likely.
A couple of commenters here seems to be provoked by the Drake equation. Since some of the uncertainties in the equation are unlimited, then the uncertainty in the outcome is also unlimited.
That is for sure.
But that does not mean that the Drake equation is unscientific.
It is a useful framework for discussing the probabilities of finding extraterrestrial life. However, since the probability for life to emerge has unlimited uncertainty, the outcome has of course to be just speculation. But some of us like to speculate.
My gut feeling is that the probability that life evolves on a habitable planet is very low, it can very well be less than 1: 10 22nd power, which mean that we can indeed be alone.
/Jan
Jan,
http://www.scientificamerican.com/article/jupiter-destroyer-of-worlds-may-have-paved-the-way-for-earth/
IMO life is fairly common in the outer reaches of our galaxy, but rarely develops beyond microbial.
Fascinating theory about Jupiter Bye.
I think life is rare because even the most primitive life forms are extremely complex structures.
Life can be viewed as a machine that is able to replicate itself in the nature.
No machine ever created by humans is close to that in complexity. So what are the chances for creating such a machine by pure randomness? I would expect it to be a very seldom event.
/Jan
Life didn’t arise randomly. It arose out of chemical and physical processes.
It’s not much of a leap from self-assembling complex organic compounds to the simplest replicating “organism”.
If that were true, why hasn’t anyone been able to provoke such a “not much of a leap”, in many years of trying, BD?
It is sad to see people so very gullible about this . .
Habitable Zone.
This means absolute nothing. In our solar system we are just at the outer edge of the “zone”
Venus is on the other edge.
Looking at Venus from another solar system will tell you that its 189 K and very cold.
Looking at earth will tell you that its 255K .
Lots of objects in space have a Black Body temp in this range. Non of them needs to have running water. There are no liquid water on Venus, not because its cold, but because its hot!
A Black Body temp is not a suface temperature.
Earth is in the middle of the habitable zone, Mars is the outer edge of it.
Until life is found on other star systems, the drake equation will remain unproven, IMHO.
Even then, it will still remain conjecture as two examples are not a sufficient sample from which to pin down most of the equations variables.
Amazing. I had to hop over a huge burden of comment to arrive at LT’s opinion, which is only simple wisdom. All this discussion is tantamount to (and about as worthwhile as) a college freshman BS session.
I would be inclined to describe the Drake Equation as fantastic numerology: playing with numbers to embellish a fantasy. Of the portion of comments that I read, no one really pointed out that there is no significance to whatever the Drake Equation purports to describe. It is an utter waste of time. It cannot be falsified; we do not know if we have all the terms necessary (unknown unknowns) or in what functional relationship (power laws?). It is so redolent of “settled science” that I prefer to sniff at skunks. At least they are truth in packaging.
“One in 10 billion trillion is incredibly small,” says Frank.
I disagree. I think it’s large. I just depends on the context.
Will we require space aliens to get a green card?
According to the “The Day The Earth Stood Still” remake, they’ll require each of us to get a “Green” card.
Did Putin Just Out The World’s Ruling Class As Reptilians?
“Putin said that he was not one of “them”, but they are afraid of him and have attempted to lure him into their “ancient Babylonian cult.”
Putin said that mankind has been manipulated to become “unconscious” through the use of programming by media and politics, the perfect example of which was the recent Panama Papers leak. The world’s ruling class have tyrannical control over our food, water, and air supply, and they are actively dumbing down the masses.
The evidence, ancient and modern, is enormous,” he said.”
http://yournewswiredotcom/did-putin-just-out-the-worlds-ruling-class-as-reptilians/
I don’t really care about the question, but I will be concerned if they show up ala Rod Serling’s To Serve Man https://en.wikipedia.org/wiki/To_Serve_Man_%28The_Twilight_Zone%29
“…It is possible that a civilization advanced enough to travel between the stars could visit or observe our world while remaining undetected.[107]” — Wankerpedia
“We come and piece.”
“Thanks to NASA’s Kepler satellite and other searches, we now know that roughly one-fifth of stars have planets in “habitable zones,”
from https://en.wikipedia.org/wiki/Kepler_(spacecraft):
“[…] The photometer points to a field in the northern constellations of Cygnus, Lyra and Draco, which is well out of the ecliptic plane, so that sunlight never enters the photometer as the spacecraft orbits.[37]
This is also the direction of the Solar System’s motion around the center of the galaxy. ”
There is an illustration on the same page that shows this corresponds with the low density section of the galactic disk between Sagittarius’ and Orion’s arms. I doubt this can be directly extrapolated for stars in the whole galaxy. The majority of stars are in the arms and closer to the center of the galaxy, were stellar structure is much more compact and complex, full of dual, triple and quadruple systems as well as open clusters.