Calculating The Odds of Intelligent Alien Life – Jill Tarter

Translator: Ido Dekkers
Reviewer: Ariana Bleau Lugo (Music) The basic question is, does life exist beyond Earth? Scientists who are called astrobiologists are trying to find that out right now. Most astrobiologists are trying to figure out if there’s microbial life on Mars, or in the ocean under the frozen surface of Jupiter’s moon Europa, or in the liquid hydrocarbon lakes that we’ve found on Saturn’s moon Titan. But one group of astrobiologists works on SETI. SETI is the Search for Extraterrestrial Intelligence, and SETI researchers are trying to detect some evidence that intelligent creatures elsewhere have used technology to build a transmitter of some sort. But how likely is it that they will manage to find a signal? There are certainly no guarantees when it comes to SETI, but something called the Drake equation, named after Frank Drake, can help us organize our thinking about what might be required for successful detection. If you’ve dealt with equations before, then you probably expect that there will be a solution to the equation, a right answer. The Drake equation, however, is different, because there are so many unknowns. It has no right answer. As we learn more about our universe and our place within it, some of the unknowns get better known, and we can estimate an answer a bit better. But there won’t be a definite answer to the Drake equation until SETI succeeds or something else proves that Earthlings are the only intelligent species in our portion of the cosmos. In the meantime, it is really useful to consider the unknowns. The Drake equation attempts to estimate the number of technological civilizations in the Milky Way Galaxy — we call that N — with whom we could make contact, and it’s usually written as: N equals R-star multiplied by f-sub-p multiplied by n-sub-e multiplied by f-sub-l multiplied by f-sub-i multiplied by f-sub-c and lastly, multiplied by capital L. All those factors multiplied together help to estimate the number of technological civilizations that we might be able to detect right now. R-star is the rate at which stars have been born in the Milky Way Galaxy over the last few billion years, so it’s a number that is stars per year. Our galaxy is 10 billion years old, and early in its history stars formed at a different rate. All of the f-factors are fractions. Each one must be less than or equal to one. F-sub-p is the fraction of stars that have planets. N-sub-e is the average number of habitable planets in any planetary system. F-sub-l is the fraction of planets on which life actually begins and f-sub-i is the fraction of all those life forms that develop intelligence. F-sub-c is the fraction of intelligent life that develops a civilization that decides to use some sort of transmitting technology. And finally, L — the longevity factor. On average, how many years do those transmitters continue to operate? Astronomers are now almost able to tell us what the product of the first three terms is. We’re now finding exoplanets almost everywhere. The fractions dealing with life and intelligence and technological civilizations are ones that many, many experts ponder, but nobody knows for sure. So far, we only know of one place in the universe where life exists, and that’s right here on Earth. In the next couple of decades, as we explore Mars and Europa and Titan, the discovery of any kind of life there will mean that life will be abundant in the Milky Way. Because if life originated twice within this one Solar System, it means it was easy, and given similar conditions elsewhere, life will happen. So the number two is a very important number here. Scientists, including SETI researchers, often tend to make very crude estimates and acknowledge that there are very large uncertainties in these estimates, in order to make progress. We think we know that R-star and n-sub-e are both numbers that are closer to 10 than, say, to one, and all the f-factors are less than one. Some of them may be much less than one. But of all these unknowns, the biggest unknown is L, so perhaps the most useful version of the Drake equation is simply to say that N is approximately equal to L. The information in this equation is very clear. Unless L is large, N will be small. But, you know, you can also turn that around. If SETI succeeds in detecting a signal in the near future, after examining only a small portion of the stars in the Milky Way, then we learn that L, on average, must be large. Otherwise, we couldn’t have succeeded so easily. A physicist named Philip Morrison summarizes by saying that SETI is the archaeology of the future. By this, he meant that because the speed of light is finite, any signals detected from distant technologies will be telling us about their past by the time they reach us. But because L must be large for a successful detection, we also learn about our future, particularly that we can have a long future. We’ve developed technologies that can send signals into space and humans to the moon, but we’ve also developed technologies that can destroy the environment, that can wage war with weapons and biological terrorism. In the future, will our technology help stabilize our planet and our population, leading to a very long lifetime for us? Or will we destroy our world and its inhabitants after only a brief appearance on the cosmic stage? I encourage you to consider the unknowns in this equation. Why don’t you make your own estimates for these unknowns, and see what you come up with for N? Compare that with the estimates made by Frank Drake, Carl Sagan, other scientists or your neighbors. Remember, there’s no right answer. Not yet.

Comments 100

  • What a sweet and beautiful voice! I was able to go through the entire video because of it.

  • The thought of there being a massive amount of other intelligent lifeforms is scary :0

  • The way i see it, if we are here, and we were able to develop all this technology, then it's 99.9999999% chance that it's happened elsewhere in the Universe. there's no reason to assume or believe that Earth or Human intelligence is somehow special. It's almost absurd to think there isn't something equally and far more developed out there.

  • Voice getting me sleepy

  • Oh, I thought this was the ASMR video..

  • The drake equation is terrible, starting from R*. It makes the assumption that all born stars are born in a habitable zone in the galaxy. This is a grotesque assumption given that the bulk of stars – the vast bulk of stars > 99% of the stars, are born either in the galactic core or the rotating arms of the galaxy where forces of gravity and rotation are known to frequently devour and destroy nearby stars, and anything that isn't destroyed is scoured and sterilized by unbelievable amounts of radiation. Fail.

  • Nice voice

  • The possibility of extraterrestrial intelligent life is infinitely remote at this time. Zero Xenomorphs. It's all about us humans. 100% H.Sapiens Sapiens so far. Not bad. The more humans we make, the more to spread through this galaxy in the coming millennia.

  • Her voice…….love

  • very informative and to the point

  • Have you not seen the hundreds of UFO videos on youtube that have been taken by ordinary people? Or the UFO's that go past the moon, or the ISS? I have also seen a UFO on an afternoon in the heart of London high up in the clouds. In short, all of this means that aliens are already visiting us but seem to have nothing to learn from us and/or do not want to 'interfere' with our history and thus, they are not contacting us. However, I still find it perplexing as to why they visit us! Perhaps, they are curious and visit us because they can!

  • I have better chance of inheriting the hope Diamond than of finding life in outer space

  • Great video!!!Great narrator!!!Great animation!!!

  • Good video insofar as it goes, but the real equation for N has factors that astrobiologists will not allow because they do not fit in with their faith-based religion, so are summarily rejected.

  • The softness of her voice makes this sound like ASMR.

  • Nobody:

    Drake equation: @+s’#)@+’@“x’@“#(wkxxkh x ksjdh x kakhs = 1

  • Well if the universe is infinite, then that’s an infinite number of galaxies and systems and planets, with an infinite chance of life. Even if the chances of life were 0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001%, there would be millions of life harboring planets.

  • Wonderfully clear explanation. Yes our uncertain longevity is the beast in the paradox ! Will we tame it ? OR will it silence us? The universe does not care. And we must care enough to change what needs changing to secure humanity,s future. ‘the answer, dear friend, lies not in our stars, but in ourselves ‘ !

  • HAHAHAHAHAHA what a joke …take a look to a probability of life origin first .. taking into consideration that other life forms exist is purely be living

  • Qualude Science, programming for those on serious depressants.

  • Well if this, the original 'third rock from the sun' is any indication of intelligent life in the universe; one has to wonder why the entire universe hasn't imploded yet.

  • It is likely that when they receive the signal we are already extinct.

  • We haven’t considered WHY an intelligent extraterrestrial civilization would send a signal unprompted. It’s hard to do even by accident. What if another civilization evolves a way to send information globally WITHOUT radio waves. What if they’re as technologically advanced as say humans in the late 1800’s?
    And what if extinction by nihilism is inevitable? If a society solves all of its problems, there is then nothing to drive progress or purpose, and thus society collapses and goes extinct.

  • The equation is incomplete. It leaves out the Skinner's Constant (that quantity which, when multiplied by, divided by, added to, or subtracted from the answer you get, gives you the answer you should have gotten)

  • The one variable that is commonly left out of this equation is that chance that some civilization, say a few billion years ago, figured out how to break the light speed barrier via wormholes or space distortion. If so, these "people" could have flown their intergalactic craft all over the universe, stopping at every habitable planet and throwing a handful of "seeds" out the window. All it would take is ONE planet out of several trillion galaxies. This is no bigger "miracle" than the big bang itself.

  • That equation looks like my normal hand writing (no one can hardly read)

  • I will save you the affirmation from any other source the answer is 100% yes.

  • Such a beautiful soothing voice.

  • Why doesn't anybody ever factor in time. time is the difference between a civilization existing and a civilization extinct. why does everybody assume aliens are far more advanced if you are the factory in the equation with time it says they're parallel to us and if they're parallel to us why are we the only ones using radio waves. There are better ways to communicate long-distance it's called light

  • it's a nice asmr vid with a brain melting topic

  • The answer is 42

  • According to ancient astronaut theory…

  • Her voice is so calming and comforting🥰

  • Can I pay her to read me bed time stories??

  • Female Bob ross

  • Equation of IFs. No answer.

  • There’s are plenty aliens on Earth, but many of them are lacking intelligence!

  • The odds are simple: Guaranteed.

  • Wait what if other intellegent beings are at the same level as us, they are also trying to find others

  • I estimate that an exoplanet with signs of primitive life affecting its atmosphere will be found by about 2026 – 2030, and then 2 more will be found shortly after, and then nothing for a little while.

    I also estimate that an intelligent species originating about 30,000 light years away will be discovered in 5,000 – 15,000 years time, or, rather, they will discover us.

  • It’s a lot easier to believe that in the beginning God created the heavens and the Earth. Easier but much less satisfying or realistic given that we now understand the size of the universe. It wasn’t that long ago when we believed that the Milky Way was all there was.

  • it will be answered when area 51 will be stormed soon

  • L ∝ 1/{mE}

    The Longevity of a given civilisation is inversely proportional to the ultimate influence of the {male Ego} on that civilisation.

  • 然後呢 。

  • "인류의 동행자(alliesofhumanity 닷 오알지 (.org)", "우주의 삶(새매세지 닷 컴 (.com)" 저자 Marshall Vian Summers ,

    를 읽어보시기를 추천합니다. 알지 못하는 지금 지구의 상황, 우주에 대해서 알려주는 책입니다. 저는 이 책들을 읽고 ufo나 외계인, 우주에 대해서 1도 관심이 없다가 이런 저런 정보를 찾아보게 되었습니다.

  • The Drake equation is flawed because it doesn't take into account the number of times life spontaneously started here on Earth. It happened one time in 4.5 billion years that is a fact that is left out of the equation. This fact makes the chances of finding sentient life anywhere near us in the universe very miniscule.


  • This lady gonna talk about equation like I passed my math classes 😂😭

  • We’ll know once the Area 51 raid is over

  • All I hear is "blah blah blah blah blah blah blah! I use big words and grammar to seem intelligent to others!" In a calm voice

    Seriously though, she's being so vague, it's actually pretty boring to listen to

  • Overwhelming and depressing. 🙁

  • Why do we need to perform a calculation? Can't we agree that there are probably intelligent aliens out there?

  • This isn't science, this is REALITY.

  • oh i did actually. The answer decreases as the type of civilisation (kardashev scale) number increases. Its 5.079 for type 1. I have my own equation to prove it.

  • I wish they would consider

  • It is impossible for there not to be other life. To justify this you need to understand the numbers. Walk on a beach, any beach think about all the grains of sand on that beach. Then add them to all the other grains of sand on the earth it's alot. Then think about space. There are more stars than grains of sand on the earth. I believe we are stuck on the very edge of the known universe for a reason. We are in quarantine. Imagine the damage we would do with our greed, warring, religion's and moronic belief that we are the most important things in the universe. The truth is we are a parasite the real 'alien' as depicted in the film. Maybe intelegent life will one day contact us. If we ever evolve into intelegent life.

  • Well the odds against amino acids randomly form correctly is 10 to the power of 104 billion .thats if the ocean was full of them for 4.6 billion years.
    the number ti add in the drake eqaution is
    far higher than just assuming habitable planets can ecen have a origin of life event.
    Thien proteins are also a enormous odds against them randonly forming.
    the origin of life requirements are so much higher than it is that the universes creation turned out like it is.

  • Anyone here 7 years later?

  • Yes, her voice is calming,but it's just TOO calming! Can't make out the words as it's hard to focus when it's like the voice is lulling me to sleep. And that makes it totally the opposite of captivating and redundant as a lesson video. Her words are not articulated, it's just like she's humming a melody, making it really difficult to understand. Now that might work for an asmr video or whatever, but not here.

  • this is wrong on so many levels

  • I figure the odds for sentient life existing in our universe is 10^72 to 1. There is still a question in my mind as to whether the human race will become the 1.

  • It seems like if wisdom keeps up with or is slightly ahead of what is technologically possible, that would favor a larger value for L.
    If technology outpaces wisdom, it seems like the L value would be smaller, but doesn't necessarily mean that life would extinguish itself in those situations. If technology kills a lot of a life form that developed it, that life form could sometimes gain the wisdom to handle that technology well enough; though it would be through a more destructive process that would have higher risk of extinction than a life form that considered how to use a technology wisely before or during development of such potentially destructive technology.
    It seems like questions about whether it can be done should also consider whether it can be done safely, ethically, what potential consequences it might have, and whether it should be done.
    Additionally, it seems impossible that with all the stars that exist that ours would be the only one with intelligent life. Even if it were extremely rare, it would still have happened many times. We just don't know how to find or communicate with such life yet. Our fastest signalling would take years to get to even the closest stars. For many of the stars out there, if they sent that type of signal now, it would not reach us for hundreds, thousands, or millions of years. It seems like it might be more of a question of whether there are any types of signals that could make communication easier, or how could we detect signals from intelligent life, rather than a question of whether intelligent life exists elsewhere.

  • Carbon based life (the only life we know of) requires water and some sort of energy source (food) to survive. We don’t know, but theoretically, there could be other types of life, like hydrogen, oxygen, nitrogen, phosphorus, sulfur, iron, magnesium, and zinc, or silicon. None of these exist on earth and are just theorized but because of this any planet could potentially contain intelligent life. The odds of us being the only intelligent life in the observable universe is 1 and 3e+21. As for carbon based life we have only seen 5 planets with water thus far but we only know these have water because we can tell that the atmosphere is majorly water vapor, so we’ve probably overlooked many of them. The odds are astronomical, but they will most likely be very, very far away.

  • Does anyone remembers Sheldon?

  • So whats the progress now?

  • At this rate of self destruction, we will only be hable to communicate during 100 years only. So that means L = 100 years for a humanbrain like speces.
    when someone will finaly hear us, we will all be dead by far

  • Any outside intelligent life will for the most part in structure, similar.
    Similar ways of feeling pain, similar way of absorbing nutrients. Uhh, some other things. Emotion, neural cells, cells in genral. Maybe not an oxygen breather though

  • With 400 Billion planets in the milky way it is almost sure that there is intelligent life if we can answer one more question – what is the need of life?

  • I'm in 2019

  • I was quite sure that here in comments I'll find discussion about her voice.

  • aliens=pseudo scientific rubbish to justify somebodies salary

  • I just woke up from a nap

  • I strongly believe there is life out there, no matter how unlikely life is. Remember that the universe is so unimaginably big that it is bound more this once, even if we never find or hear them.

  • very calm voice lm going sleepy this time

  • The answer is always 42

  • Theres the possibility that life would happen only in this solar system still.

  • I would like if aliens started eating humans.

  • In order for humanity to survive ourselves, we need to take steps to understand our psychology and animal nature, and then either teach, philosophize, or engineer our killer impulses out of future generations. Stable, peaceful, humanity is the foundation of a future both on Earth, and elsewhere in the cosmos.

  • OK so let's forget about lizard-monsters taking over the earth. I propose that ALL life becomes human after enough evolution. But what, after we evolve, is human?

  • Seti already received an answer back… You're just to naive to see it or accept it.

  • pointless equation and pointless video

  • Drake Disapproval: Drake Memes
    Drake Approval: Drake Equation

  • There's alien life visiting Earth now but of course Academia can't study that fact, their required to play the head in the sand game which the U.S. Government dictates through ridicule, ridiculous explanations, threats and control of funding. Here is where you go to see just one small piece of the evidence for alien visitations: @t
    and here's where you go to learn all about the Government(s) cover-up: @UCnaIeNm-jSa1l8yHrn7PlQg

  • Sorry humans, we vulcans can't communicate with you, you don't have warp speed technology yet, it is our prime directive

  • here are the results with out doing math … Zero. LOL HHAHAHAA

  • QUIT thinking organic. Non-organic can live anywhere, and actually have more mental capacity. Just ask your computer. Start thinking AI and everything (…except your silly emotions & memories) is possible. Read my book.

  • Never tell me the odds

  • Best ASMR I ever heard

  • honestly, the best is to avoid any form of, ever…

  • I don’t really like the voice. I think I like Addison Anderson voice’s better. This one seems too quiet.

  • Frank Drake:
    “ E.T do you love me, are you out there.”

  • What a load of BS

  • There is only one planet with life on it and the astounding balance of nature up on it. And considering that we have a limited time of life, fulfil every given minute with happiness, kindness and love. And most of all, say thank you, to the One that has created us and all the majesty that surrounds us ☺

  • Are we the only life in the universe because there is another thing in the universe that is similar to life but isn't life at all yet it is very intelligent. Maybe life is a step before reaching this other form of being and once we go past being just life our technology will be so advance that technology like that can't exist next to our simple life without destroying it instantly.

  • Alien commentator

  • Have our signals reached Proxima Centauri?

  • It boggles my mind that people from 2 million years are going to look at us and laugh how primitive aur knowledge of universe was, exactly how we look at cave men. We went from cave men to us in modern times in year 2020 in less than 14,000 years, how primitive will we be to people 1 million years from now

  • Let us assume that Earth is the only planet with intelligent life and then solve for LONGETIVITY Factor.

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