Do ALIENS exist? | An astrophysicist's perspective
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- Äas pĆidĂĄn 8. 06. 2024
- Are we alone in the Universe? Although there's no evidence for life elsewhere in the Solar System or beyond (yet!), science can at least help us work out if alien life is likely or not. To learn something new, head to brilliant.org/drbecky and sign up for free!
More on the Hubble Ultra Deep Field (HUDF) image: svs.gsfc.nasa.gov/30946
00:00 - Introduction
00:35 - How many galaxies are in the Universe?
03:19 - How many stars are in the Universe?
04:45 - How many of those have planets?
07:14 - How many of those are habitable?
09:11 - Will we ever communicate with alien life?
13:04 - BLOOPERS
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đ©đœâđ» I'm Dr Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
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The one saddened thought I find is the universe might be teeming with life, however, just in different time periods. As one civilization is born, thrives, and becomes extinct, another one surfaces. Never converging with each other. The number of stars the universe has might be a big number, but it doesn't compare with time. All in all, there might be an intelligent civilization out there at the same moment we are in, but the chances of them being here at the same moment in time, within a distance we can communicate with is very small. This is where the great silence comes in. You would figure if there was millions of civilizations, you would at least hear the after glow of their radio signals even with Doppler shifts in their light and the attenuation of light signals through vast distances, but we have heard, a very disturbing, nothing.
Even more disturbing is Cixen Liu's Dark Forest theory of cosmic sociology. Basically from the two axoims of survival being a primary driver of civilization and that matter and resources are limited, any civilization would arrive at a conclusion that other life is an existential threat, as the evolution of civilization in recursion with technology is asymptotic. Meaning the reason that other civilizations can't be seen is that they do not want to be detected and being detected means being snuffed out by civilizations that understand this prisoners dilemma. Like hunters in a dark forest.
It's pretty existentially terrifying to think about. Love that.
plus you must consider that a civilization doen't necessary have the means to communicate with us. If you think about it, if an alien civilization tried to communicate with us 100 years ago we wouldn't even noticed it...
It's actually more interesting if there is no other life anywhere in our galaxy. Then we can populate it as we see fit -- Klingons, Vulcans, Romulans, Ferengi, etc. We are bound to be disappointed in life forms created by happenstance.
Might only detect their signals if they were close enough, which means relatively close even within our own galaxy, when it comes to other galaxies, except for our immediate neighbors you can barely even see the galaxies themselves without powerful equipment, when you get to galaxies outside the 'local group' there's no way I don't think we would be able to detect red shifted remnant signals from a civilisation, the signals would probably have to been generated with the energy greater than whole stars, where just the wasted (unused/uncaptured) energy was on par with that of a star and happened to be 'lost' in our direction, but I doubt a civilisation able to generate that kind of energy would do so in such a wasteful way, then when you get to galaxies multiple superclusters away... In terms of civilisation density our grouping of galaxies could be the equivalent of the Galapagos where it feels like there's nothing around us, but heading out in almost any direction could lead to continent equivalents of civilisations, that analogy might even be true just within our galaxy for all we know. But the time gap does add a whole extra dimension
@Shedding you are not taking into consideration what a tiny little fraction of time we have been listening. Not to mention it may be in a frequency that we are not advanced enough to detect. Also any super advanced civilization may be nanotechnology, that is a lot more efficient
âSpace is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space.â - Douglas Adams, The Hitchhikers Guide to the Galaxy.
Well given that the volume of the universe is infinite there must be an infinite number of worlds. But not all of them are populated; therefore only a finite number are. Any finite number divided by infinity is zero, therefore the average population of the Universe is zero, and so the total population must be zero.
Douglas Adams restaurant at the edge of the universe
42
@@barneybiggles I knew we'd end up with that answer. Isn't someone going to say the problem with space travel is all the numbers are awful?
The real question is how big is the biggest alien space craft....its at least 75 miles wide because ive seen 3 at one time all about that size, huge. All at the edge of space and glistening in the sun and looking like 3 crescent moons.
The machine from the books that kills people by showing them just how big the universe actually is would definitely work, star gazing gets a bit vertiginous for me sometimes.
the fact that im not currently having a full-on existential crisis just speaks to dr becky's skills as a presenter. literally can't stop watching this is my new comfort place on the internet
"either we are alone in the Universe or we are not. Both are equally terrifying.â - Arthur C. Clarke
"...And pray that there's intelligent life somewhere up in space, 'cause there's bugger all down here on Earth!" - E. Idle
You forgot the two most intelligent lifeforms on earth, dolphins and white mice.
"Can we 'ave your liver, then?"
Given the preponderance of flat earth videos on CZcams and crazy creationists trying to debunk evolution I'd say there is ZERO chance of intelligent life staying on Earth.
So long, and thanks for all the fish.
@@vinnyganzano1930 Flat earthers are growing in number with new members joining from around the globe.
I love that self-deprecation is the new "in thing".
Oracle, are we alone in the universe?
"Yes. You are alone in the universe."
So there's no one else out there?
"There are others but they are all alone too"
This sums up the situation perfectly.
@@timsmith5339 It also makes a lot of baseless assumptions about technology and the very nature of reality which we do not have a grasp on yet. It's hilariously arrogant to apply this to the real world.
Fave commentâ„ïž
@Chip in4seven its called a quote, buddy.
You should read that sf story called "Blindsight", there's even a fan-made trailer for it on youtube.
Where were you Dr Becky after all these times? You just came out of thin air and there you're all over the place with wonderful informative videos!! I like them all, also love your accent. Lovely !
One thing that needs to be taken into account is that the distribution of life won't be uniform. So it'll only form in regions with right conditions you've stated. Therefore one would expect that if there are other places with with life they will tend to cluster. Also we need to take into account that perhaps there are many other ways a planet might become habitable. We assume that being on a planet in the Goldilocks region of a star is the way to do it, but perhaps being on a moon that receives heating through gravitational tidal forces might be another. Or perhaps you might have life were energy stems from chemical energy or planetary heat rather than stellar energy.
Yep. Definitely there are factors that could create life-supporting conditions outside of the envelope we'd normally expect (sort of like the deep sea vents on Earth) - but likewise there are other factors that will undermine otherwise habitable planets, like Mars' lack of a magnetic field allowing its early atmosphere and water to be blown away into space, even though it otherwise looks like a pretty good candidate for a life-bearing world. So these will mess with the real outcomes as well.
Excellent point about some of the conditions being locally co-extant though. Whatever cosmic events seeded our solar system with heavy elements almost certainly did so for many of the nearby stars as well. It also means that the Milky Way as a whole is likely old enough to have a large number of late generation stars, increasing the odds for it as a whole to have other life-bearing worlds vs. a galaxy several billion years younger than ours, which would be much less likely to enjoy such conditions.
Good points. I think many scientists make the same points from what I have read about moons like Europa and Enceladus as well as different exoplanets.
It is HIGHLY unlikely there are more than a handful of intelligent civilizations in the Milky Way, perhaps we are the ONLY one, although there could be hundreds holding primitive life out of which intelligence never evolves beyond simple animals or even bacteria. Most likely we will find intelligent life by spotting Dyson swarms in very distant galaxies.
Life forms elsewhere may not be carbon-based. Theoretically, it is not impossible for life to be based on other elements or combinations thereof, or other particles - photons, neutrinos, etc. , or may not require chemical energy for sustenance. Who is to say there are not many permutations and combinations that could yield life of some form, and ours just so happens to look like this. The question is, how do we even define âlifeâ, and how would we recognise it when we stumble on it, if it is not similar to what we are used to? There might be life swarming around us, but we are unable to recognise it.
Letâs hope so, because 100.000 planets where life can exist seems a very small number. And I fear if we are the only intelligent species that space might have to do without intelligence some day.
-Are we alone in the Universe?
-Yes, we are
-So there is no other life in the entire Universe?
-There is. But they are also alone.
Is this your quote or is it someone elseâs?
@@danswansonguitar someone else's
@@juriskrumgolds5810 thanks - do you know who? Can you share?
true
That is such a joke. They have been always on that planet and there is plenty of evidence
When I was in high school in the early 80s, I attended an open lecture by Carl Sagan who was visiting the University of Toronto. His topic: the Drake Equation. There was such a demand for tickets that they held it in Convocation Hall which has a 1700 seat capacity. It was packed. Seeing him talk in person and do the math on a blackboard was completely enthralling. 'Billions and Billions.' :)
Wow, so cool! That would be incredible to see. How lucky!!
I remember that he also covered that in an episode of Cosmos. It would have been amazing to see him go through that live, though.
My envy for you knows no bounds!
And the math on self destruction ? That was the blinder !
You were one of the lucky ones!
Once when I was a child a math teacher told me that he was very respected everywhere when he said what his profession was. My father, upon hearing this, said: âDon't think he's intelligent, he's just an expert in calculations how a mechanic understands engines." Many years later I realized that it was pure truth, as a professional information analyst is much more informed about what is happening on the planet and beyond (about extraterrestrials) than a qualified scientist immersed in intergalactic calculations. And this information contradicts everything that the scientist believed in his unquestionable calculations.
Just saw this... One thing I find amazing that, if there is life out there in the universe, it may not at all be life like we know it. You defined the "goldy locks zones", but that does not mean that life could not have evolved elsewhere; only life as we know it. Its fascinating!
Like those two methane breathing aliens in a bar, sipping there ammonia fizzes, complaining about all those useless water worldsâŠ
100% of explored star systems have life.
Given the sample size (1), there may be some bias to adjust for.
You're just talking about human-explored star systems, though đ
While I think there is life out there, the thing that bums me out, is I am starting to lean along the lines of 'due to physics constraints, hardly anyone can contact anyone else due to how hard it is to push a good signal that far where it will be still useful, and the time involved anyway, probably far too late for many civs , and even if any of those civs do reach communication due to proximity to each other or something, transportation is not there, or at least none to our nearest neighbors that are probably out there, so we might as well be alone'. I'm not sure if that can ever change, even if we had lightspeed motors with infinite power, which is also impossible.
Yeah, the laws of the universe here I think work very well against us. While it is nice to imagine some sort of Dyson sphere civ out there, I also think that is wishful thinking, and unlikely as hell, personally. Due to well, physical realities that they would have to break through to do it, which we see as impossible now, but I don't necessarily buy that there is even a solution to even for a super, super intelligent race.
And none of it intelligent... very sad.
You call this one explored?
0 degrees of freedom
It's like telling the Earth: Love is out there, but you're probably not going to find it.
Damn, the Universe can have a dark sense of humor.
Might be for the best. If they anything like us not sure it would be pleasant meeting
@@thatisme3thatisme38 well if they find us now and don't like us existing here they will be able to do that. They have FTL tech. they are highly advanced. if they did not care about the planet they would probably just need seconds to annihilate us all. if they wanted to minimize risk for them and the existance of earth they would just shut down our satellites and wait. it would not even takemonths for civilization to collapse. after that they could just march in and kill all survivors.
@@roberine7241 well it's my point exactly
@@roberine7241 If they have FLT technology and the calculating power to navigate the universe without slamming into random shit, it probably wouldn't take them more than a few hours to synthesize a self replicating protein that ate humans and whatever else they didn't like around here...
@@andersjjensen you probably don't need that much computig power. At least not every jump. you just have to create one 3D map with all the places you should not ever jump to and done. but yes they could probably just engineer a bacterium or a virus to remove wshat they don't like.
I love how you take us from the smallest unit of which we know, and extrapolate it to the universe that we can see. It makes it a lot more comprehensible.
Found Dr Becky from being on Answers With Joe and Iâm now hooked! Amazing stuff. Thank you for your hard work.
Also, subscribed. đ
great video, I think its also worth noting that all these calculations are based off the assumption that life can only exist in the way we know it. There may be many variations to the requirements for what is required in order for life to take shape across the universe.
right. life on this rock needs O2.. but on other planets it could be noxious and fatal. we have no idea. and look at plants.. they make their own food. that's what we need to do. but because we don't we're designed to kill things so that we may continue living. plants don't do that.
Yes, in listening to her commentary, my thoughts were the same.
We've never observed anything else. If theories of non-carbon-based life were developed then tested in a lab then it would be reasonable to include them.
If this is unsatisfactory then you can view this estimate as a reasonable lower bound.
@@willis936 fair point but i feel this argument could be used both ways. we've never observed any type of intelligent life outside of our planet, so making the restriction that life can only work in regulation with our small sample size of the universe seems to me a bit brash. nonetheless i think we can both agree that at the least this estimate is indeed a reasonable lower bound.
Not exactly Raziq. Yes, it is a narrow view of what life could be (and maybe we can't even imagine it). But is not restrictive as "the way we know it". The only real assumption is that it has to have liquid water in the surface. There are no assumptions regarding the kind of biochemistry, ADN, ARN, cells, photosynthesis, forms of reproduction, etc.
For me, the Hubble ultra deep field is the most beautiful picture ever taken of the universe.
At least, right now, or that humans will ever see. If this lecture was anything to go by, other civilizations probably have just as beautiful (and more beautiful) pictures.
I have it set as my computer desktop background.
Mine is about 80 megs. It's nice to zoom in and look at.
I think itâs equal parts beautiful and terrifying.
@@Hyoscyamus369 Disagree. If people really understood that image they would realize we are pretty much alone and we need to take care of this planet because "nobody" else will - there's no one out there to help us or even knows we're here.
New to your channel, and enjoying catching up on your content. Thank you for sharing your knowledge.
It seems like when we have conversations, we are talking about life as we know it. How unlikely is it that there are beings out there that are not in a form that we know?
Space is just so mind boggling! It's great to have stumbled upon this channel on my internet ramblings, and am currently working my way through all these videos. A wonderful human with a vast knowledge and an evident enthusiasm that is an infectious joy to behold x
Iâve never felt simultaneously smaller and yet so in awe at the scale of space than while looking at the HUDF image.
It is truly stunning!
i agree, it's astonishing how large "space" is xD
@@kapa1611, yeah, space is everywhere you look!
@@kapa1611 What gets me is that I understand that it is in fact so huge, yet I know at the same time I can't actually conceive of something so large. I'm no scientist, but I've tried to explain it to people a few times that no matter how big you think it is, think bigger... and do it again, and again, and just keep going...
I find it humbling to the extreme. I realise that I don't mean shit as I look up and even just to our nearby neighbours like mars and Jupiter. We're all so small and yet so self important.
@@kapa1611, space and time are 2 things that can never be measured. they just simply are!
The fact that galaxies that are 1e5 light years across are still held together by gravity, making it work at such scale, is mind blowing.
I like to point out something if anyone is interested. They are not held together by the supermassive black hole in the middle. Because gravitational force is disproportionally related to the square of the distance. So the mass of the black hole would not be enough to hold it together. They are held together by the mass of the dark matter. All galaxies are basically swimming in it.
bababooie
The Hubble Ultra Deep Field is my favorite photo of all time. Always gives me chills and never ceases to blow my mind.
Itâs awe inspiring & a little bit terrifying at the same time.
Soo well explained, absolutely fascinating, thank you for this
One of my favourite quotes from Star Trek: In this galaxy, there's a mathematical probability of three million Earth-type planets. And in all of the universe, three million million galaxies like this. And in all of that... and perhaps more, only one of each of us.
But if you believe in a universe that is infinitely large, or an infinite number of universes, then there are an infinite number of "you" out there. The are just fantastically far away or in other universes. So you are not unique. Sorry.
@@harrkev the odds you were born ((mind you earth is inhabited)) are 1 to the 70th power. Or in other words all the atoms in the known universe. Now what were you saying
@@jefflee1189 i know thats pretty crazy! how each and every one of us won some crazy cosmic lottery... although if the universe is infinite, well that changes things, if there are infinite copies of each and every one of us.. kinda changes the uniqueness of it all.
@@jefflee1189 but wouldn't that mean the probability of that happening is null?
â@@raidermaxx2324 well the universe had to start somewhere and i think it will end when all interaction stops ((which very popular theory)). but by then we will have reached ascension and the universe will be small in perspective. for some as many, i assume death is certain ascension if ascension is the end result. we also have AI on the horizon and who knows wth will happen then haha.
socially we're in a mess. we spend money on the wrong things. and science is highly misguided ((on purpose of course))
Ever since I started to grasp the sheer size of the observable universe it always seemed almost unfathomable for life not to exist on other planets
No matter how large the observable universe is, the probability of life arising excpecially intelligent life could be low enough such that it is unlikely there is any life in the universe. Not saying there isn't any, I have no idea, just the assertion that large number of chances => must happen somewhere doesn't hold up. For instance we never see ice form out of room temperature water in spite of the small chance that it could happen because the probability is just too small.
Given the number of planets out there - even in just our own Milky Way - I'm absolutely certain other life is out there. The problem is can we detect them and are they living in a technology age at the same time roughly as we are? Those two together: detection and overlapping technology timeless make us pretty much invisible to other intelligent life.
@Joe Duke
Edit: I feel like this comment comes off a little aggressive so I want to clarify the tone I intended was to explain my position on space exploitation, nothing more, nothing less.
planets are not living entities their "health" should only be considered for other creatures sake. Which of course means we should care about earth and other worlds with life but honestly I could care less about if a random space rock remains "pristine" or not. The key distinction between earth and space is that there is nothing to ruin for someone else in space (this is assuming you've already checked for life btw), no people, no animals, no plants, no microbes. If no one does anything with it it'll remain a lifeless husk possibly until the heat health of the universe. So we might as well make it into habits for life ourselves.
I also think life in general is a net good. Whether that's true or not is not a debate I'm getting into but I certainly want our decendents (of all types) future to be Dyson swarms and enough artists/scientists/etc to dwarf the number of people who have ever lived. It's incredible to think about.
Dieter Zerressen the overlapping technological ages is something rarely mentioned, even by academics when discussing the probability of alien life. Taking into account that dinosaurs lived for roughly 200 million years, but have been extinct for about 60 million years, and man has only been able to fly for just over a hundred years, the chances of finding life forms that are close to our own level of development, and close enough to make contact, must be close to zero. Think about what she said about the Voyager, 75,000 years before the sun is no longer the nearest star! What was man doing 75,000 years ago, or will be doing in 75,000 years time? But 75,000 years is really just a blink of an eye in the universe time line.
@@Dang3011 I mean yea, but the dinasours wouldn't have died out if they had a space program. I mean that might not be the whole story but you get my point right? Once a species has a good enough grasp on reality they can actively take steps to avoid there own destruction. They could also destroy themselves somehow so trying to predict how long intelligent life originating from earth will be around is a bit of a crapshoot could be a few centuries or until the heat death of the universe and we don't really have a good idea where we will fall on that scale.
This is very clear and better paced than some of Dr B's later presentations, which tended to get faster and used 'gapless editing'.
For the general maths and what is "out there", this presentation is outstanding.
Just came across your channel last night! Hands down one of my new favorite channels if my my most
your videos are the best
that is all
The real problem is it's impossible to estimate how likely life is to exist on a "habitable" planet. We don't know how life came to be, there are several theories on abiogenesis but nothing specific enough to calculate probabilities. It's possible that every second planet with liquid water has some microbes on it. Or maybe it's less than one planet per galaxy. It all depends on how likely the mechanism that turns non-living things into living things is to occur. It might be relatively straightforward given the right conditions or it might be extremely unlikely.
If we include microbial life then we have not even exhausted the possibility of life within our own solar system let alone in exoplanets. However I think we have more or less exhausted the posibility of multicellular intelligent life within our solar system.
If you ask me I hope we never get to actually meet intelligent aliens. If we go by our own history on earth ; all the wars and genocide; we can be certain of one thing . Any encounter with intelligent aliens is not likely to be pleasant. Either they will wipe us out or enslave us OR we sill wipe them out or enslave them. History will repeat itself.
Not only that, but the notion of "habitable planet" is completely unscientific and undefined. It varies from scientist because we simply do not know if the assumptions that are being made about planets found using astronomical methods are truly as described. It's just wild guesswork (wishful thinking) on their part.
@@chuckschillingvideos except Astronomers donât mean habitable for humans when they say habitable, right? It only describes the lowest common threshold they can think of, proximity to the sun so liquid water can exist.
That is a precondition necessary for any type of necessary chemistry to at least be possible.
All the other factors after are not taken into consideration yet.
@@gamingnscience Astronomers are no more able to determine the requirements for the initiation of life than anyone else. No one knows. Period. Their wild speculations about what is "habitable" and what is not are based on....well....hunches and wishful thinking cloaked in words that sound like science but are not.
@@chuckschillingvideos you didnât read what I said. The astronomerâs definition of habitable is just the first threshold of liquid water.
There are a bazillion other thresholds we are less sure about, but if this one isnât met, you can effectively stop looking at that place.
Itâs the one condition we can be relatively sure about and agree on.
But you are right, that alone is not enough to guarantee life.
Just pointing out the misunderstanding between larger population and astronomers.
Astronomers are often failing at naming things adequately to prevent these misunderstandings.
Thank you for all your passion and energy. So positive, engaging and informative. I really enjoy your videos.
Your vibe is so great in this video. It looks like you're wearing a robe and have turned down the light getting ready to read me a bed time story but are excitedly postulating about the very nature of life and the universe. You are the grandma I want to be when I grow up.
Also your analysis was great and I agree the short answer to most questions like this always comes down to the fact that humans live on a comically small time and space scale compared to the universe.
I love how scientists answer this question. Both the question and the answer are simple, but the reasons and method for obtaining the answer are so much more complicated.
After watching this I am reminded of Bill and Tedâs advise: â Be Excellent To Eachotherâ
That was ... Pretty cool!
You explain some really complicated ideas and facts very clearly. Sheeet, even I understood. You would be a great teacher.
đ
This is one of the best breakdown answers of the question I've ever heard!
When we look at the number of things that we have questioned about space over the years and we look at the amount of photo evidence that many times we were, in fact, holding at that same moment but didn't yet know how to be interpreted. These two thoughts combined lead me to wonder how many other civilizations are already in our database and we just don't know what we are looking at
It happens on Earth as well. For many decades it was thought that the "Hittite" people were fictional as the only reference to them was in the Bible. There weren't any Hittite artefacts found at any dig site. However with the increasing translations of Egyptian documents it was found that the Hittites did exist and their artefacts were quite plentiful, they'd been misidentified as "Assyrian".
Our assumptions guide our interpretation of data.
Fingers crossed for JWST! Love your content Dr. Becky
Not long now!
December 18, 2021 launch date.
âDo not be surprised if we confirm alien life outside of sol within the next 5 yearsâ. I donât even remember which jwst video I saw that had this quote, but Iâve been so giddy ever since lol.
Love the bloopers. Great video!
Loved the way you explained this. Great job!
Yeah, contact with intelligent alien life is a long shot. I'm actually more optimistic the non-intelligent kind -- it happened relatively quickly here on Earth -- and the best shot of detecting that is to "sniff" the atmospheres of exoplanets (reflected spectra) and see if we can detect any evidence of life-based activity.
Yes I wont rule out intergalactic mold
Is this where I make the usual quip about "ain't no intelligent life here either"? đ
Even if you detect what you think is a spectral signature of a planet with life, there's still no way to verify it
@@Mike-qc8xd I agree. I've got some intergalactic mold around my tub and it's impossible to remove. đ
@@oliverwilson11 Actually, there could be. A possible detection would generate a very healthy debate over how to confirm or rule out claims that biological processes are responsible, and there would be a lot of effort put into improving the sensitivity of the measurements in the hunt for more evidence. For example, it might eventually be possible to image the planet's surface, and if it turned out to be a mix of greens and blues...
There could be many different types of life that exist beyond the habitable zones of stars, under ice caps near thermal vents, or even in other places we haven't yet considered. If we find anything on Mars or in the moons of Jupiter or Saturn it will dramatically change how we think about what else could be in the universe. Love the video, thank you!
Watch Europa Report.
Europa is a favorite for exploration by scientists, as there is strong evidence of it having large amounts of liquid water beneath its surface, probably kept liquid by internal heat generated by tidal stresses from Saturn. However, its still a poor candidate. It is going to be very, very cold beneath those ice sheets, and chemical processes (which life is), become exponentially slower with every 10c you reduce the average temperature. No solar radiation for energy also means almost no energy gradient to work with, unless its lucky enough to have active volcanic vents far down beneath the frozen surface. Even if those exist, they would represent minuscule islands of chemical energy and complexity where evolution might be lucky enough to kick off. Chances would be excellent that it has never done so - even if the potential is there, or that it has, now and again, and then died off as a given vent goes silent, allowing the eternal cold and dark of the Europan ocean to close in around it.
So much enthusiasm for your subject and so well explained
A very informative video. I enjoyed watching this. Thank you for sharing your perspective.
Halfway through, you finally got to the point I usually make: that the other galaxies are so vastly distant in both space and time that whatever life forms may exist there, we will never be able to detect them. So the question with respect to other galaxies is entirely academic, thus not interesting. The interesting question is: what are the probabilities of life in some form, and of advanced civilizations, in The Milky Way? If you knew that, you could make a good estimate for the entire observable universe.
The problem with getting the probabilities is that we can only make hand-waving arguments which, as you note, have huge error terms. There are only two ways to get a good estimate of a probability. The first is by sampling. The second is by analysis of a model. The difficulty with the first is that we do not have a statistically sgnificant sample. We know of one star system that harbors life. Until we sample enough star systems to find more instances of life, we canât make a good estimate. As long as we only know of one planet bearing life, we could be unique in the galaxy, or there could be (or could have been) many thousands of planets with advanced life forms.
The difficulty in the second case is that we have no model for the origin of life. We know how simple chemical compounds are made, so can predict what will happen when we mix them in particular conditions, but we do not know how to make the first self-replicating molecule. All we have to go on is the time it took for life to begin on Earth. That is an insufficient sample. The probability could be anything, because we do not know what events were important to lead to life, then to advanced life.
"diddiculty" - I like that word. đ
Yess, the 2nd case. Throwing in the statistical probability of creating some form of life from a known chemical cocktail in a water environment? How many planets in the goldilock zone that had a moon to stabalise the orbit for long enough, with a magnetic core to shield from radiation and a stable star , that had the right set of meteorite impacts at the right time to cause the chain effect of evolution for a plant to make oxygen and a skeletal frame that created creatures able to transition from the sea to land and in the right time frames between extinctions. It's a difficult model to create and make into some mathematical equation. It's easier to say that there is other life on other planets. But how many with cognitive awareness of their own existence? That is a mathematical model on top of another mathematical model in my non-scientific opinion. So that narrows it down even further.
It's on a knife edge that we even exist at all. And we have only been around for a couple of million years. Those odds have got to be incredible, in my book. đ€
That's a very good point. But, imagine if there is no end to space ? So, just looking at our universe, is just a start and it's really all we have at the time. But, the vastness of space is probably, so much larger than we can even imagine, it's really much more than the brain can even comprehend in the evolution of the brain itself. Come back in 1000 yrs and see !!!
Never say never. Our understanding of the Universe and physics is extremely primitive. We have only just began to explore our reality. Who knows what strange and amazing science we will discover in the coming thousands to millions of years to come!
@@mexdal Great point. we have NO idea WHERE others may be on the time scale. absolutely none. this system has been around 4.7B give or take. however other systems have been around 3 TIMES as long. this means they have a HUGE "jump" on us. HUGE! take a look at the crop "circle" pictogram in response to Drake & Sagan's message sent via Arecibo in 1974. yeah WHAT is going on there? these crop pictograms are being created in MINUTES and there's hundreds of them every year. how'd these beings get here? we have NO CLUE. and in fact because we have no clue these Scientists (including this one) are in complete denial.
The question "do aliens exist" has never personally interested me. The universe is big, so the answer is almost certainly a yes with even the most conservative estimates of the Drake equation. The question that interests me is if aliens effectively exist to us. That is, can we detect them, or even interact with them. That answer is seemingly a resounding no. for the near future at least.
To be fair, we barely lookedâŠ
@@juzoli We've been scientifically looking for decades
@@ninjanolan6328 Exactly. Mere decades in a universe where everything is measured in million years.
We couldnât even detect ourselves from more than about a hundred lightyears away. And other civilizations might be less âleakyâ than us.
If they noticed that we are here, and sent us a radio signal directly, which is the most likely thing to detect, then it is probably not even here yet, as a few decades is not enough for that.
And if they donât have radios, (we are talking about life in general) we donât even have tools to detect the signs of life on the closest planets.
The thing is we've been looking for signs of civilization. We have found a lot of planets that potentially have the markers of life. But it's more of we haven't really had the opportunity to seriously look yes we've had Rovers on Mars but there are areas on Mars that very likely might have some form of life and we purposefully haven't sent anything to those for fear of contaminating it. Because life is delicate and something that we are accustomed to dealing with whatever that is may not be assuming they're made of the same thing we are and they developed a similar fashion I mean at least early on
@@borttorbbq2556 We donât even know about the planets which might potentially have life on it. Mostly we can only see gas giants and other bigger planets. We need better telescopes to see Earth-like planets.
she makes me appreciate more what we have and thus should take great care of it. THANKS!
I clicked on this video and realized I had seen this already within the first 5 seconds... I'm not ashamed to say... I watched it all the way through again. lol. I love your cannel!
Really clear to non scientists. An exceptional episode. Thank you.
Hoping the algorithm blesses you. You seem pretty chill and your channel is up there with like Joe Scott, Scott Manley, Issac Arthur, etc
Engaging, articulate, very pleasant voice
A great combination for a CZcamsr
Surely the fact that we can only define âcan support lifeâ in terms of how we understand life to be supported, goes right to the very heart of how limited our capacity to make even the vaguest informed guess is?
Sample size of one makes everything a guess. We just need to find life in one other place no matter how small and we can get a much better estimate.
I enjoy the enthusiastic and animated way you compose these presentations.
You are top of my list as a dinner guest!
And she's HOT !!
Extremely interesting, but at the same time mega-mind boggling. My mind has trouble trying to compute the figures involved in the universe. But I don't suppose that I am the only one.
Yeah, and thats based off what the telescope catches. Maybe the liggt of further galaxies just doesnt reach us. If it is endless....
No, you aren't the only one.
Beautiful explanation. Thank you.
Your video was amazing. It made a lot of sense and you kept it interesting. Thank you.
Although it seems likely, the amount of habital planets needs to be balanced against the chance of single cell life to occur and evolve. That we don't really know.
There's plenty of evidence to believe that the emergence of the sort of complexity needed for life should be quite common in places with the right ingredients and free energy.
the chance that single celled life evolves is hard to know, ya. but there are other things that we can learn/assume by looking at life here on earth.
for example.. how often single celled organisms became multi cellular (i heard estimates that say it happened 20-30 times) or another fun question is what multi cellular groups have the potential for being intelligent (obviously plants will not be intelligent because they lack a brain, not matter how long they evolve for xD) so the only group that could be intelligent is animals.
i kind of wish people who talk about life elsewhere in the universe brought biology into it more. because it's obviously relevant, since we're talking about life, but also because it seems like intelligent life (essentially that means only us) is extremely rare. it literally only appeared once, out of god knows how many species. so 1 over the number of species that ever existed on earth, could be used as the likelyhood for intelligent life to emerge on a planet where the conditions are right (as an estimate) xD
We cant assume life took the same route that it did on Earth. There could be other ways for it to have developed, using other forms of chemistry.
@@DavidBeaumont I think if it were that common, we would have recreated the process ourselves by now, but I don't believe we have.
@@DavidBeaumont Please, don't say lies. There's no evidence because the abiogenesis process is unknown. Unless you are calling evidence to something that is not actual evidence. We don't even know and we cannot calculate what's the minimum autoreplicating molecule, and much less, what's the chances of it appearing. Earth have all the ingredients for life, it has free energy, and life emerged once. There's no life spawning everywhere. All lifeforms have a common ancestor and no life is emerging right now on earth. Which indicates the opposite: the window of abiogenesis is so small that there's not even competence in our planet.
I feel like re-reading your book now. Good timing too considering (and you didn't hear this from me) that a new one may be coming out đ
What's her book called ? I need something new to read
@@zibafu Space At the Speed of Light
@@rexnerf Is it available for Europe?
Gotta love her Enthusiasm. She'd be Such an Awesome teacher.
This video makes learning about space science fun
Never been so early. The excitement is real.
Also, I bought a book called *Force + Motion* today for 25 Euro's and its soooo worth it. And the fact its an academic book makes it even better.
Big fan of your videos and people (scientists) like you keep me excited for when I enroll on physics & astronomy (possibly +mathematics as double bachelor) in 2023 at Utrecht University.
Keep up the work Becky. And if you got any recommendations for astrophysics books. Let me know.
So, about Avogadro's number of stars? A mole?
that settles it! god is a chemist xD ;)
6,02214*10^-23 .... not 26 ... My teacher would find the right words, I don't. Just, no.
@@chriseffpunkt4333 maybe i'm misunderstanding your comment, but avogadro's number doesn't have a negative exponent (that doesn't even make any sense, since it's the number of atoms in a mole, and that can't be a fraction)
and idk where you're getting 26 from, Jeff was talking about the number of stars in the universe which (by one estimate..) was 10^23 (10^12 galaxies, with 10^11 stars each)
explain?!
@@chriseffpunkt4333 ??
A gopher? Sorry, no caffeine yet. I'll see myself out ...
Man this stuff just blows my mind. Near impossible to really comprehend how vast the universe is
Anybody that thinks we are the only life is dreaming..., will we "discover" life..., that's a different question. Another brilliant explanation by Dr. Becky. :))
I could literally listen to you all day, great content presented excellently.
Your content is amazing. Thanks for all your hard work!
Loved this! But 100.000 habitable planets in the entire universe? I donât know to me that sound astonishingly small I thought that number would been higher
Those are only the ones that have been discovered, there are probably many millions more hidden by gas clouds, planetary rings or odd orbits
Good stuff young miss.đđ€đ and well presented. The logical approach is the only approach đ. Your a new favorite of ours.keep up the great work đ đ
5:40 there was a new study published early this year about formation of the heaviest elements, where authors claim that these are formed not only in supernovas but (primarily) in mergers of neutron stars (as well as some rare types of supernovas).
Yes, but that applies primarily to 'genuinely heavy' elements. The majority of a (Earth-born) living being's chemistry is composed of oxygen, carbon, nitrogen (and hydrogen!) atoms, which are produced in the CNO fusion cycle active in large mass stars. This said, life as we know it on Earth could not exist without at least some traces of heavier elements (zinc, iron, selenium, calcium, sodium, potassium, magnesium, copper, fluorine, ...) - most of which are still produced in/disseminated by supernovas. The 'really heavy' stuff like gold and uranium is what seems to be produced predominantly by neutron star mergers.
true! and itâs a really interesting study that shed new light on the formation of elements.
but remember: Becky said âheavier elementsâ. and sheâs an astrophysicist. to an astrophysicist, anything beyond helium is a âheavier elementâ lol
I would like to point out that we know that _most_ stars occur in multiple star systems. Binary or trinary systems or even more. In these systems there are serious questions that _any_ planet would support "life as we know it." We also know that a significant fraction of the stars in any given galaxy are within the nucleus and galactic bulge where the levels of radiation and interaction of stars is considerably higher. Which is not to mention the number of stars in globular clusters. Even if such structures only have stars interacting every couple million years that is enough to cause orbital problems with the planets around any of these stars that could possibly destroy the ability of any _potentially_ habitable planet to support life long enough to evolve complex life forms.
Taking this into account, some researchers have postulated that only perhaps four to eight stars in our own galaxy could have life on them at any given time. Or even less.
As far as intelligent life is concerned, even given those huge numbers Dr. Becky quoted, it is _not impossible_ that we are the _only_ planet in the universe to have evolved intelligent life. However we have a grand total of points of evidence of one, so we can't even begin to speculate about the likelihood of life (much less intelligent life) on other planets. It could be common. It could be unimaginably rare.
great comment (imo)!
it's interesting that the only example of intelligent life that we have is us. which is actually a little surprising considering that life on earth existed for a couple of billion years already. and multicellular life existed for at least a couple of hundred million years.
so intelligent life must be extremely rare.. as you said, we only have one example of a planet that has life, but if we assume that it's representative (it may not be, in either direction, but hey, it's what we got xD) the likelyhood of intelligent life on a planet with conditions that sustain life could be 1 over the number of species that have ever existed here on earth.
and viewing it as a likelyhood could be misleading, since we know that certain lifeforms can't be intelligent (it takes a brain to be intelligent, and plants don't have one, and no matter how much time they are given to evolve, they won't develope them... only animals seem to have the "potential" for intelligence and again, even there it only happened once)
@@kapa1611 Totally agree. And like Hawking said life is just a chemical scum, no big deal anyway.
@Betatroll "radio capable" is a very practical definition of intelligence here xD
YOU ARE AMAZING! Thank you for sharing this at a level laypeople can understand
The best thing about Dr Becky is the BLOOPERS.
Just showing that she can and will make fun of herself.
đđđđ
Just watched the Nova series part five that was all about Black Holes. Congrats to Dr. Becky for being one of the guest commenters! She was even the last commenter as the show ended! It was a terrific program & I learned a lot about Black Holes. đđđđđđđđđđ
I've always been of the mind that it's more than likely that life developed "out there" somewhere because life developed here, and it seems that nothing in the universe happens once. Probably the biggest (or more commonly implied) question would be whether or not the alien life would be either intelligent or anything we'd recognize as life. I have a feeling a lot of people are going to be disappointed if the first aliens we meet are bacterial.
I agree
That's more or less a guarantee. Evolution of true multicellularity is one of those things that might be considered a very hard step in life. Our version of it anyway. It's expected the large majority of planets with life would consist of "bacterial" mats. That's still the find of a lifetime, though!
Perhaps the real question isn't "is there intelligent life in the universe?" but rather "are we considered part of intelligent life in the universe?".
Earth has experienced 5 major Extinctions and several minor to medium Extinctions due to various reasons, such as Oxidation events, Volcanic eruptions, Rogue Asteroids, and Ice ages, Viral and Bacterial, plaques. If Earth lacked tectonics. deep Ocean Thermal vents, the existence of Fungi, White Ants, Viruses, Bacterium, and trillions of mutations, etc.. Without most if not all of these major and minor extinctions, events, mutations and life, and our moon, I assume that we would not be here. To imagine that something evolved remotely similar to us on another Planet is beyond my comprehension.
Bonus comment.
I hope to leave the world the same way my grandfather did; quietly, peacefully in his sleep, not screaming and crying in terror like the passengers in his car at the time...
I just can't raise any enthusiasm whatsoever about finding single celled life elsewhere. I would expect it to be relatively common on Dr Becki's 100,000 planets, but of no great import. I couldn't care less. Anything higher than sponges or jellyfish would certainly be of interest, vertebrate animals extremely interesting but extremely unlikely.
Best answer to this question ever!
Love your videos! New subscriber!
Hi Dr. Becky, I just saw you on the latest episode of NOVA đ€Żđ€Ż. It was incredibly interesting and thanks to your videos, I was able to recognize and understand most of the concepts that were talked about. Anyways, it was a great surprise to see you and I hope you have a wonderful rest of your week :)
Thatâs awesome! Hope you liked it, it was fun to film đ„ł
"Do aliens exist?"
Abductee: Yes
Lmao
"Did you communicate with them?"
Abductee: No my dream ended soon
No joke, people are having terrifying encounters and others ridicule them - they can't believe it, can't handle the implications. The most important thing happening on Earth, happening without acknowledgement from the general public. Please read The Allies of Humanity
@@bdlfontaine3240 If a civilization has the ability to travel faster than light there are a whole host of other fairly straight forward assumptions we can make about them. Including but not limited to a much more thorough understanding of biology, and a much more thorough ability to decode and decipher any systemic signal they might come across. There is absolutely ZERO reasons for them to abduct humans and stick implements up their bum. There would be much more efficient ways for them to go about getting the info they want without direct interaction.
These crackpot stories about abductions are just as dumb as religion, and they bear every hallmark of being conjured up by small minds who do not realize the contradictions in their own statements so we end with stupidity like "An all power full God who knows everything, can do everything and transpires time itself.. but you can't eat this apple! And you must treat him like a self obsessed power tripping king with a fragile ego or you'll be punished for AL eternity!"... AKA a depiction of a ruler who is like the ruler of the author of the story....
Same with these abduction stories: They're so full of "If humans were aliens, what would they do?", but conjured up by simple minds who have no concept of science, sociology or even biology.
Also, why is it that it's always drunks, loners, the socially challenged and people with mental diagnoses who gets abducted, and never Stella from the nice neighbourhood? That is not very good sample material if they want to understand humans (and can travel faster than light, but have no stealth technologies....?!?).
Humans should build automated space ship, that visit other planets, and obduct the species for scientific studies. (including the necessary probes and cloaking technology)
Fascinating subject! I need to reread my copy of Sagan and Shklovsky's "Intelligent Life in the Universe."
Well, you're my new favorite astrophysicist
Thank you, a hugely interesting summary of these incomprehensible numbers.
I'd attend her lectures without fail. Well done Dr. Becky.
Smart lady. What a mind. Thank you for your vid. Stay in the game your presentation skills are excellent.
Enlightening young and mature minds.
You touched on a perspective that I had forgotten when doing estimations for the probability of life. In star life and time in the Goldilocks zone. One thing that has frustrated people and scientists alike is the stark lack of evidence, the universe is so vast and yet a resounding silence is observed. Life seems to be very improbable at a biochemical scale, so improbable that it might imply a mechanism other then random chance is responsible for the inception of life. Where randomness is only a key that turns in a self organizing lock rather then expecting order directly from chaos. The size of the universe implies that the dice can be rolled enough that even the Extremely unlikely event of a self replicating molecule sufficient to spark evolution into complex life could happen millions of times and we would see evidence of it. But with numbers under say 1e20 it becomes unlikely and when itâs a scant 100000, itâs nearly impossible. And that would explain why we canât find any evidence.
Thereâs life but not as we know it. Thanks Dr. Becky for your stream. Martin đ
"It's life, Jim, but not as we know it".(Dr. Leonard "Bones" McCoy of the USS Enterprise)
Perhaps life doesn't have to be organic and exist in similar scales and dimensions to us. Maybe we're separated by those, as well as by distance and time? Just thinking that we may be pre-judging the answer, but within those confines, an enjoyable and informative answer. Thanks, Dr Becky!
If it is not as we know it, we wont recognize it anyway.
Wow, my mind is blown!!! Great stuff Dr Becky
Beautiful breakdown from a beautiful astrophysicist
A great and informative video, thanks.
Absolutely loved the video. Any thought on doing another to include the issues we would have regarding time. I also believe there are other civilizations out there, however, them being around at the same moment in time? Well thatâs a whole new ballgame.
11:23 I firmly believe that life must exist somewhere out there in the vastness of space.
I believe in Batman
while I believe in the flying spaghetti monster
@@elck3 Praise be the Flying Spaghetti Monster! Always a joy to meet a fellow Pastafarian.
100%
I donât know how many of you were around in 1950-1960s but there were so many sightings of strange hovering craft that there were local civil defense meetings about how to respond to their presence . Iâm not talking about swamp gas or ball lightening. They were metal they hovered for hours sometimes irregardless of wind or weather conditions. this has been suppressed and forgotten over time. I am pretty certain they are here already and may have been here for some time.
Very good Dr. Becky
We may be alone in this Galaxy. I read that our moon keeps our spin stable otherwise you would have wild annual temperature swings instead of the mild changes we have. Also we have an extra large iron core courtesy of the moon forming Collison which gives us strong magnet field radiation protection. So don't we need to add to the many exclusions, having a huge moon via an early planetesimal Collison ??
Not mention Jupiter and Saturn being tidally locked, so the gas giants didn't drop closer to the Sun. Lots of things are responsible for life on Earth that may not be true for other planets in their Goldilocks zone.
I agree. Too many people are way too willing to think that aliens are next door. It seems that all skepticism goes right out the window when talking about aliens.
yeah, we have to be very proud that we exist. its incredibly rare. lots of factors alligned for a life to emerge. life is beautiful and we have to cherish it.
I think you are right on about this. Our existence depends on so many things that have come together in just the right way that it's possible WE are the only "intelligent" beings. Watch Dr. David Kippings video about this subject, he gives a good argument for this possibility.
@@bigedslobotomy I'm convinced Valarie Jarrett is a Reptilian.
I'm so impressed about your love and knowledge about astronomy!
Which I share!
As an 55 year old man from Sweden, you are a light in the sky for me. And many others, I imagine.
Keep it up, my "friend"!
So true
Thank you Benny!
I read the also chapter of your book and I am watching this video.
What I feel like is important here - live took a lot of time to evolve on earth. During this time, earth was really active and it existed in the correct distance from it's host star with an atmosphere, magnetic field and active tectonics (volcanoes) and weather (lightning). How many of those exoplanets do have these conditions for long enough to have primative amino acids to develop and even proto cells, bacteria.... So I am glad you included it.
I loved the video. I sent it to my grandsons. They love your videos.
What is an astrophysicist's favorite key on the keyboard? The space bar!
The bartender adds way too much "foam"...
Suddenly I feel like I've been in the Total Perspective Vortex.
The answer to everything is 42
Thanks Doc nice presentation
Hubble deep field changed my view of the Universe!