Honestly man, your knowledge, presentation, and most importantly, your narration skills, are otherwordly. The latter is what keeps me glued to the screen and never notice when minutes fly by. I'm infatuated.
In terms of narration, apart from Brian Cox so far the only one who can convey the awe of science as succinctly. Really love the shit out of these videos!
Prof Kipping, I hope I can get to the point to be able to financially support the work you do, as the sheer amount of enrichment and education I’ve gotten out of your channel is immeasurable. Till then, thanks to everyone who can and does support, and thank you doctor kipping for continuing to bring us these amazing videos
Thanks to GroundNews for supporting this episode! Head to ground.news/CoolWorlds to save 40% on the Ground News unlimited access Vantage plan with my link. Let me know if you think Earth-like conditions are common or rare, how special do you think we are??
This video seems to go against your paper 'An objective Bayesian analysis of life's early start and our late arrival'. We are orbiting around a third generations star. There has been a ton of time and space for life to develop into civilizations if life is easy to form, yet we seem to be alone.
Ground News is a good sponsor. I like them. I use them. Good information -- good information _sourcing_ -- is essential for being a participant in democratic society.
LUCA is usually "last universal common ancestor". Lowest doesn't really make sense because lowest suggests the earliest, presumably somewhere back in the fuzzy weirdness of abiogenesis
LUCA means all life descend from this ancestor, it doesn't mean it's the first, just that this ancestor is the ancestor all modern life descend from. LUCA is not the first self-replicating molecule.
To me, the terrifying solution to the Fermi paradox is that life is common but so short that the chance of two civilizations noticing each other are infinitely small. We pop into existence that would be noticeable and disappear so quickly that anyone watching our solar system blinks and misses us.
Or... The rare earth hypothesis is true... And complex/intelligent life is extremely, extremely rare in the universe, because you need goldilocks conditions fore life to evolve to that point. Maybe Earth conditions are so extremely rare, that we are alone in our corner of universe. Despite life being so easy to thrive.
@@ianthor22 I’m afraid that solves nothing. If a civilization was broadcasting for 300 years, you still have 300 years to detect it when the waves pass by you. The fact that they travel forever does not help at all.
There are thousands of possible solutions. Coming up with solutions isn't the issue. The issue is proving them. This, just like every other possible solution, is totally inconsequential.
@@ianthor22 Our radio communications are only detectable at 1 ou 2 light-years away from Earth. If we were trying to actually send a signal to outer-space, that could change the numbers significantly. But at best we would be able to deliberatly send a detectable signal to a hundred light-years planet. By the way, our galaxy has a radius of 52 850 light years.
This is why it's usually best to resort to Bayesian inference to decide statistical probabilities. The human mind is not good at interpreting statistics and can easily fool itself. Then we have various cognitive biases to deal with.
Long form content that I watch multiple times to catch all the nuances. Man, don't ever change. You are one of the best things online, not to say on RU-vid. Thanks.
I'm glad you finally raised those caveats at the end: just how "earth-like" (this is likely a multi-dimensional "parameter") must a planet be for statistics like these to be calculable? Moreover, we can't exclude the possibility that some verrry different variety of life may arise & evolve in a similarly different environment. We can't begin to address these questions until we've surveyed a multitude of exoplanets in great detail. Or at least until we find microbes on Europa or Enceladus. At the other end of this, I agree with Steven Hawking that encountering an exo-civilization is dangerously inadvisable, as the likely disparity in level of development may mean that one will overwhelm (e.g., destroy) the other, or that the greater will regard the lesser much as we currently view colonial insects, or corals. 🦖? 🐒? 🦜? 🐠? 🐝? 🦂? 🦠? (?!)??
Your voice is perfect for this stuff, the cadence is unmatched and really emphasizes on peoples curiosity, and affects the ability of our attention spans to really get in and watch it all the way through. Thank you, keep up the great work.
Seriously RU-vid.. stop putting ads in mid-sentence. When it comes to science and lectures this is ridiculous it takes away from the content. Thank you Dr for another excellent experience.
RU-vid premium is actually worth it. Content is so much more enjoyable without ads and your video views support the content creator just as much as if you had sat through the ads.
Since RU-vid started making the advertisements more and more punitive, I consider it a moral imperative not to reward that with payments. Customers... Demand better.
Man I consider myself lucky to get to hear you talk. Thank you for the way you approach topics and your honesty while presenting facts. You are one of the best modern educators out there.
I am not of a sciency background but love astronomy and astrobiology and sciency things..I really found myself not understanding the technicalities of the video (frustratlng) but watched and tried to grasp as much as possible..thats the sign of a good teacher, to inspire..this is indeed exciting stuff!
Not necessarily. Bacteria cause infections, but have you ever heard of an archaean-caused disease? Archaea are extremely common yet the only health conditions associated with them tend to be imbalances in the already extant microbiome. Granted, archaea are more closely related to eukaryotes (and multicellular life) so maybe alien microbes would be pathogenic, but considering alien microbes would have nothing to do with our own biological processes then it would probably only be sheer coincidence if they're harmful.
Pathogens jumping hosts happens but between mammals. Anything more different just isn’t compatible. If the world doesn’t have multicellular life they aren’t adapted.
@@yannicmodritscher4646 True only for viruses. A bacterial form of life could adapt to more or less any environment with a supply of nutrients - e. g our bodies. It would then very likely produce chemicals toxic to us.
@@MarshmallowRadiationThat's weird, I was pondering earlier today how we were taught back in the day that archaea were simple bacteria, and that viruses were one of the five kingdoms in taxonomy. How things change.
@@yannicmodritscher4646There are these recently unearthed mimiviruses that have allegedly caused upper respiratory infections, but they don't seem to be infectious.
Complex life has had multiple hard resets through extinction events just in the past 600 million years. It's just not something that can ever be calculated or predicted in a sample size of one.
Another thing. COMPLEX multicellular life only has about a 700 million year history. So much had to evolve, AND atmospheric O2 had to sufficiently increase to cause more bioenergetic pathways to evolve. In addition, what if a large meteor had NOT impacted Earth 66MYA? Would we be here now??
Need to be looking more into Earth's evolution, it's like looking for a needle in a haystack with no haystack until they know more about how life emerged here let alone anywhere else.
@@simoncove1 Possibly, though primate brains are legit just built different so probably not. Though we would certainly see non-avian dinos adapt to the glacial conditions of today’s Greenland and Antarctica, so that’d be cool to see
@@yancgc5098 small mammals did exist tho even back then so maybe anyway…. Might be inevitable give a planet like earth and long enough. Also yeah the continents allow ecological niches but yes let’s face it…. Who knows?!
Saving this for bed. Thanks in advance for another thought-provoking video. Just finished watching this. I firmly believe that life started quickly but developed slowly. Things like the boring billion were necessary for the development of more complex life. A great channel for the evolution of life is The History Of Earth.
Three thoughts: 1) Evolution rate is quite variable. The coelacanth, sharks, and alligators are all examples of life that have changed very little of hundreds of millions of year. Human could considered the fastest evolution rate since we have clearly definited intelligence yet have not beeen around very long (relatively speaking). The real trick of there being other intelligent, and even space faring, races is what factors sped human evolution and what would the maximum for those factors be? Even on a planet with a shorter life span or less ideal conditions an intelligent race could evolve if the evolution factors were strong enough for force it without reaching extinction levels of stress. 2) Planetary life span is only being calculated based in non-interferrence. If a species becomes intelligent enough and aware of issue affecting the planatary life span, they could take actions to reverse or slow down the dying process, gving them time to evolve and advance more. 3) Even if life on the surface of a planet becomes overly stressful, it could move underground and still develop to become intellgent and spacefaring. Basically, life finds a way.
I think what you've done is just rule out life around F type stars, which we kind of suspected anyway. But you also don't rule in K type stars which give around 10 times more time than G types. Also one of the great filters would be Eukaryotic life. It may be that 3bn years of Prokaryotic life could be anything from at the earliest, an average or a latest event before the first Eukaryote.
Another assumption is that evolution would typically take so long before sparking into complexity. What if some environments push evolution hard so it has to adapt a lot and often? Between the two assumptions and the sheer number of chances out there, I think life, even intelligence, might still be common enough. I did find his point on the window that life has to do these things very eye opening when I first ran across it, and while his point does lean on our experience alone since that's all we have, it could be valid enough to reduce many chances across the galaxy.
Great presentation. One problem is that due to the inverse square law of radiation it is very unlikely that we could ever detect a signal from them. Basically think of stars that we can detect planets around. The sun is the transmition power and the planet is the modulation power. The reciever is a telescope. What is the most distant star we can detect planets around?
Nothing excites me more on YTube than a new Cool Worlds video. This doesn't disappoint. A dream vid would be David in conversation with Brian Cox. Guaranteeing a million views!
@@ksh95If you knew almost nothing of the universe this assumption should be pretty logical to make. It shouldn't have blown out minds when learning it is a fact
IMO: any reference to Earth is (largely) irrelevant. All that really matters is if there are other planets with the key features needed for life to start in the first place. We simply can't answer the likelihood of such via reference to Earth.
My argument is still that the problem with the Fermi Paradox isn't how common life is, but how can we detect it? If our best means of detecting exoplanets and exomoons is watching for a dip in luminosity in its star, how exactly are we going to figure out that life exists there? If a planet is 200 million light years away and evolved life 100 million years ago, how could we possibly ever detect it? Yeah, we look for radio signals, but how do we know aliens would even use radio, or communicate via sound in the first place? What if aliens evolved a system of visual or written communication only? What if they communicate via chemical signals, like many microbes do on Earth? That's really my problem with all of these equations, we are operating on the assumption that intelligent alien life would look something like us, but there could be any number of hidden variables changing things. I simply can't accept that Earth is the most unique planet in the entire universe, that sounds like hubris to me. The probability that life does exist but we don't currently have the technology required to detect it seems much higher to me. Call that wishful thinking if you want.
To be fair, as David has pointed out many times, there really are two variants of the Fermi Paradox. What he calls the "weak" Fermi paradox is why we haven't observed aliens. What he calls the "strong" Fermi paradox is why aliens aren't here among us right now. That is also the variant that Fermi himself was originally referring to. Why the Earth isn't an alien colony. There has been plenty of time for expansionist aliens to colonize the entire galaxy, and it seems very unlikely we wouldn't be aware of it if Earth was currently an alien colony.
There are a range of chemicals not produced naturally that we could snoop in an Exo Atmo. That's strong evidence for intelligent life. But I agree with you. There are hundreds of different amino acids yet all life uses the same 21. What if life evolved using a different suite? It might turn out radically different.
That last sentence you wrote about the probability seeming higher to you is a fallacy though, that’s just a total guess that feels more right to you, but has no mathematical backing
I think we would notice if aliens had colonized Earth and were living here. We would also notice if aliens had started building Dyson swarms around all the stars, or were tearing them apart for materials. In fact we probably wouldn't exist in both scenarios. That is the Fermi paradox. There has to be a rate of life. There is no reason that number can't be incredibly small. Like one in a trillion, or one in a trillion trillion. The fact life exists on Earth gives us 0 information. If life didn't exist here, we wouldn't be here to observe it.
Its a rare earth, but we have half the planet fighting the other half because one persons book of fantasies has the chosen one be born in a mud hut in an area now inhabited by another group. Very sad.
But this would mean that the probability of developing technology is an even bigger filter than I thought before. Because, if life has really sprung up even earlier than assumed previously, it means that the period until technology was developed elongates as well. And that means the act of getting technological is even harder than we might otherwise think it already is. And for the search for intelligent life that might mean we're actually now less likely to find some, because of how rare it now seems to be.
Short answer: very, very far away. I find it stunning that few people tend to grasp the implication that the vastness of space brings. Even if one assumes there are a million civilizations roughly equivalent to ours (at our stage of development) spread throughout the universe, the distances involved makes contact highly improbable, if not completely impossible at any stage.
@@siubhan2047 some communicative discord could be possible , we can't for see tomorrows tech , same goes for traversing the galaxy , physics is ongoing we nowhere near answering or discovering everything
@@CoolWorldsLab - I can't think of any reason why a sterilising impact would be necessary. Indeed if life was not present then I don't see what sterilisation means!
@@sja45uk I will posit that i am a creationist so it's not my forte (yeah i know, creationist in a evolution topic), but one of the major ideas for how life could have been sparked seems to usually require intense heat events, a lightining strike, volcanic vents etc, there's no reason to think a impact event wouldn't be able to do that as well, especially if there are ways for elements to form we haven't discovered yet, for example, earth is a rare planet with phosphorus, there's no guarantee that phosphorus or some other element could form under the rare conditions of a sterilization event impact, as it's unlikely we'll be able to even test those conditions for a long time what would happen in such of a event is only something we can make educated guesses on..
Great video. But isn't there still one factor you haven't addressed that could kill the theory? Namely, the likelihood of abiogensis. It is entirely possible that abiogensis is so incredibly unlikely that it literally never happens, except here on earth. And since we don't even know, really, anything about abiogenesis, we cannot possibly discuss its likelihood. The only stance we can take is one of utter agnosticism.
This brightened my day no end! I need to start a new sticky note now. I've been out of the loop for a bit due to caring for my mum, but I need to get stuck into things again! Thank you!
What I never understand is; If we all have one common ancestor, such has been proven. Then this means life has only begun once in 4.5 billion years. Evidently making it extremely rare! Surely answering the Fermi paradox.
We have two - at some point mitochondria were taken into single cells as a symbiotic relationship, although the details are still debated on. If we had two at one point, there could have been more that simply didn't survive later changes. Once life became prevalent its activities would make further chemical replicators nearly impossible due to competition. Life on a blank canvas may start early and often. We only have one example so far to work with.
There was an emergence of life on earth before us. Look up the Ediacaran geological period. It was about 630 million years back. All we have are the fossils but it's pretty wild
If the existence of life prevents newly formed life from gaining a foothold, then abiogenesis could happen every 10 million years, but every time after the first time, it would get eaten immediately.
No, life could've started many times. For all we know, it keeps starting all the time, just never gets anywhere and disappears before we discover it. Also, life eradictes life and traces of life. On our planet, there's also geological "life" that complicates things.
Professor Kipping, in the past especially your public lecture on the Cool Worlds Classroom Channel did a superb job in convincing me, it is likely we might be alone in the galaxy and even the universe. Like you said yourself: As the arguments in this video are only valid for an exact copy of Earth, this new discoveries about LUCA are interesting, but don't change much as we have still now idea how common "Earths" are. Thanks anyway for the entertaining and informative video!
I sincerely hope so too. If there's 'anything' that seems 'living' would indeed *change everything.* My gosh, what a tremendous finding. But then again if not, that's fine. It pushes back the hope of finding something back a bit. I really appreciate his approach to this subject. He holds reservations about finding something as if, it's gonna happen every time and every place. I'm in the same camp. Looking close into the actual mechanics that would enable life to start. All very fascinating to me.
I hope it does not. I would love it if there is life on other planets, but it would be best for us if there is no life in the solar system even a basic one. That way we will be able to expand and use the resources of the solar system to prolong life on Earth, including sentient intelligent life. Clearly, we could be gravy Aliens and just go to Europe and exploit the water and use the same reasoning used for abortion (even better because it won't be a clump of cells) but it will be divisive. Also as the activity of the Sun increases we may need to move.
Hypothetically if the Europa clipper or another project discovers independent simple life but we don't have an estimate for when that life started, how would that impact the model?
They will going to make a new copium stuff because they still want earth/our solar system be special, but the thing is, more likely life/intelligent life is everywhere, like in Three body problem
This model is just for earth-equivalent systems so it wouldn't impact but it means the universe is surely teaming with at least simple life. Honestly the problem I have with extrapolating this model out to the whole galaxy is we still have yet to even find an earth like exoplanet.
What I'm taking from this, is that LUCA arrived very, very early, which means it took even longer for an advanced species to evolve from that. Which shows how hard it was to evolve and how long it needed on a relatively stable cradle (Earth). This just diminishes the chance of advanced alien civilization emerging, as it takes even longer, even though basic life appears to arrive easier.
Prof. Kipping, if indeed we have about 900 mil years left, surely there's enough time for you to make a video/podcast about Quasars and Magnetars, right? 🙃
Well we know lots of things but when you learn one thing there's more things to learn. That's more accurate if you know nothing there's nothing to learn. 😅
As a biochemist with an interest in the origins of life I do not particularly care if life elsewhere achieved a 'technological civilization' state, but rather on the origin of what we call life, and in understanding what life is. I would issue a challenge that we can ask biologists and biochemists and most will not be able to produce a description of what life is that is truly universal, and not just relevant to terrestrial life. If the microfossil record is correct, i.e. it really represents structures that were 'alive' 3.7 billion years ago I would completely agree that life is not fussy. How long evolution takes, and the paths that it ends up in are irrelevant. It is only important for us humans from an antropocentric perspective, where we want some life, somewhere in the universe, to converge on a technological civilization, but as a biochemist that criterium is really not relevant. Having said that, I think that as life's complexity increases also its frequency decreases. As a system that is in a continuous state of non-equilibrium thermodynamically, it will also require conditions that must be stable over an extended period. The higher the complexity the narrower the range of fluctuation of environmental parameters that are compatible with that complex life. Sure evolution will enable change, but evolution also working on a species and not individual level, it will also require long periods of time of stability.
That's a great point. If we consider our own impact on our environment right now, our chances of lasting 900 million more years at this rate are slimmer than the Plack length on a vegan diet. I take it you're familiar with Jeremy England's 2014 paper on the emergence of life as a highly efficient distributor of heat? I quite like that hypothesis.
It's not merely because we're chauvinistic about technological civilization that we look for it amongst the stars. It's more the fact that we ourselves ARE a technological civilization. If we hear nothing, if technological civilization is fleeting enough that it is undetectable on cosmic scales, what does that say about our future?
@@Stadsjaap - I strongly doubt any one complex life could reasonably be said to last 900 million years as numerous extinction events seem to prove but there always seems to be another to take up the batton
@@sja45uk I completely agree. The extinction events in Earth's past completely remodeled the biosphere as a consequence. In the absence of those, Earth's life makeup would be very different. As to life's origin, and life in general, biochemically I see it as a series of events (chemical reactions or physical changes) that as a result of a continuous energy flux tend to optimize the thermodynamic exchanges with the surrounding environment. Jeremy England is one of the latest in a line of physicochemical scientists who have been looking at this problem as such (Ilia Prygogine being one who in the 50s and 60s) started looking at dissipative structures and non-equilibrium thermodynamics). That is how I see life, from a biochemical perspective). Yes, there is much we do not know, but I think some of the researchers are on the right path. But it is something that we will never know for sure, how it originated on Earth. The best we can hope is understanding its principles and perhaps reproduce it (microscopic) in controlled conditions.
The early collision hypothesis is the only way we come up with a large moon like we have. The likelihood of a Planet having a moon as large as ours is extremely unlikely for many reasons.
@@altus3278 The likelihood of a planet having a moon as large as ours is 100% *given we've seen it in reality*. Bayesian statistics gets you like that.
I think it was also mentioned in one of the Kurzgesagt's videos - that there was at least over a hundred million years old period during our Universe's cooldown where ALL OF IT (except proximity to stars and nebulas) was in safe temperature zones. In the end it went from extreme hot to near absolute zero, yet that "Universe being warm swimming pool" period wasn't insignificant. If you only think that life with its simple startup formula could cling onto rocks EVERYWHERE across time and space then not believing in Universe full of life is quite weird.
Note that Stromatolites are fairly advanced lifeforms that have developed the ability to glue themselves in place and have everything they need for survival delivered to them.
If 1 billion people bought a lottery ticket, and one of those people won, would we entertain the claim that the lottery was easy because they won it first try? now have a 1 person on 1 billion planets buying a lottery ticket.. that's how i see "life is easy because it happened quickly"
Bad comparison. I think a better one would be imagining a billion people buying 100 tickets, and when one goes home to open them, they win first try. Would you not think that winning is pretty common?
That is because you're ignoring a significant rule in this discussion that scientists usually factor in 'we aren't special'. We have no reason to believe we are special, with regards to a lottery you would have reason to believe you are special as lotteries by design must rarely payout to winners else they will lose money.
I have to confess that I'm not sure I accept that life occurring very early necessarily implies that it's likely to occur. Certainly if there were many planets like ours, and life always tended to occur early, that would be compelling. But with exactly one data point, it seems like "maybe it just happened to occur early here - regardless of the odds of life occurring". Am I missing something?
OK - I went back and reviewed it. I feel at least a little less silly now. I think we're talking about different things. You're describing the rare Earth hypothesis - which is certainly a valid consideration. Not only may it be important to have a planet extremely similar to our own, but perhaps it also has to go through some of the same changes as Earth. What I'm asking is a different question. Perhaps abiogenesis would be a very common thing under perfectly ideal conditions. But perhaps not. It could be an astonishingly improbable event even under the best circumstances. I think the notion that it occurred early on Earth is used to "prove" that it's a very likely event under the right conditions. But I'm not sure we can make that leap based on a single case. Perhaps it's an incredibly unlikely event that simply happened to occur quite early. If I'm right, we would only be able to know this if we saw how quickly it occurred on many ideal planets.
5:10 Abiogenesis has to be the most common occurence in the universe. My spouse is adamant it takes place even in completely closed off sterile systems the moment you take your eyes off of them. For example, if you forget to put away the milk cartons to the fridge the nanosecond you come home from the store, they are apparently immediately teeming with life and need to be thrown away.
That is not abiogenesis. Abiogenesis is life coming from inorganic molecules. If you had pure chemicals in a sterile container, life arising from that would be the first documented ocurrance. There are pre-existing microbes even in pasturized milk
She's not wrong, but that's because life is already present. If you mix vodka with a juice of some kind to an ABV of 9% and leave the container open, you'll get a nice vinegar just from bacteria in the air. Or if you leave the juice out on the balkony, you'll probably get a wine. Life is fascinating.
Given perfect conditions the genesis of life may be easy, but I still think that the likelihood of perfect Earthlike conditions are prohibitively rare. SO much had to go perfectly for the Earth to be where it's at right now and to be so protected from constant asteroid bombardment, and to have a sun that wasn't too deadly for the ecosystem, as well as not too close to any stellar killers like supernovae or gamma ray bursts, and there had to be enough asteroid bombardment to deposit enough water onto the planet to support the development of life, and the planet had to be big enough to keep enough of an atmosphere but not too much, and the tilt had to be good enough to allow for a proper water cycle, and so on ad infinitum. Earth, is just super, incredibly, rare.
We have no idea if any of this is significant, required, or rare, or if we're just retroactively finding connections, as our pattern-seeking brains always clamor to do. As David says in this very video. We have to live on *a* planet that supports life, but that doesn't mean there's any special significance to how that planet is. It's like assuming only white people can win the lottery because the one lottery winner you've encountered is white. Well, they can only have one skin color. Doesn't mean there's any significance to what skin color that is. All Earth's configuration tells us is that this configuration does support life. It says nothing about whether this configuration is required, and definitely not whether it's rare.
I know that many would not want to talk about supernatural factors but has anyone also considered the fact that besides life on this planet, we have the perfect conditions for PERFECT total solar eclipses? I ask anyone to calculate the odds of that occurring anywhere else in the universe of 200 sextillion stars
@@Erikaaaaaaaaaaaaa You need to pay more attention to Organic Chemistry. The complexity needed for life requires Carbon Chemistry, and the environments where Carbon Chemistry can dominate are extremely limited. Liquid water, no ionizing radiation, stable temperature range, etc, etc. All of these variables must be maintained for Billions of years. It's just the science.
"Incredible rare", well, nobody knows how rare. But it's not unreasonable to suspect pretty rare and yes, maybe indeed incredible rare. What we dó have a reasonable estimation of is the amount of planets in the known universe. An INCREDIBLE amount. Soooo.....
@@ksh95 We have absolutely no idea that carbon chemistry is required for life. For example Gerald Feinberg and Robert Shapiro have shown how one could use a system of magnetized particles as an alternative to DNA. In other words, we don't even know for sure that *biology* is required. You are building your entire thesis on a series of unproven assumptions. You might be right, but just like OP there is no way to know whether you're retroactively finding patterns where there are none or whether you're actually onto something.
funny how when they're called patrons or super subscribers nobody bats an eye, but when someone calls them "executive producers" (the holywood term for "patreon" support in the 20th century) you get suspicious. It's just monetary support, ya dingus
Confusing. First you show us how likely it is that live starts everywhere. Then you say you don't believe it because of your beloved rare earth hypothesis.
I love David and adore this channel, absolutely no shade meant to him. But yeah. This is the exact reason I got a bit worried a few months ago when he started talking about how he's started coming around to the idea that life is rare. He has argued so thoughtfully about the value of staying agnostic to avoid forming a prior belief that will bias your interpretation of any future data, including in the conclusion of this video, but I think it's hard to dispute that's kinda exactly what's happened. Using that thought experiment of dissolving chemicals in water he formed a prior belief that alien life is rare.
Professor, you can't be so optimistic. In the end, we are too far away. Too far away from anything. But, what do I know? I guess the way ahead is more important. A journey that is above the destination. Inspiring video. Waiting for the news with using your scope of choice. 😉
I.ove that you include the phrase "right now" when you say that radiometric dating is the gold standard. Even in more or less thow-away sentances, you include the possibility that our knowledge and kethods are limited. Just. Cooool. 🖖😄👍
Another explanation for the early onset of life is panspermia. A smaller planet like Mars would presumably cool down and become habitable quicker.Even interstellar panspermia can not be completely ruled out yet. That could make single celled life reasonably common in the galaxy but still possibly extremely rare in other galaxies.
It’s logical to assume that it’s highly likely that life is all over the universe given how many galaxies, stars, planets etc. exist. Many people’s egos are too big and they want to feel special, so they deny this. Sad!
What’s sad is that you’re forgetting all the necessary conditions that brought life to Earth. A high number of galaxies with stars and planets does not mean life is everywhere, as I pointed out in my post. The probability of conscious life in a galaxy is far less than one planet per galaxy; it’s actually 1 in 200 quadrillion stars (or 1 followed by 18 zeros after the decimal point, 0.000000000000000001). YES, we are that rare-to the point that we could be the only ones in the universe. It’s math and statistics, not ego. Stop listening to Neil deGrasse.
No, that is not logical because you're using unknown factors. That destroys logic. It makes no sense to say that the value of A is greater than the value of B because the value of B is unknown. I think it's arrogant for you to say that I must assume that your assumption is correct or else I have a big ego. We have absolutely no clue what conditions are required for life. We don't know that life is native to this planet.
@@jorgen7180 You’re making the classic mistake of taking a cup full of water out of the ocean and assuming that sharks, whales, octopus, turtles etc. don’t exist in the ocean because they are not in the cup. And NDT is a total nut job in my opinion. But you’d never be able to say that to him because he never shuts up.
You could have done the math for lower mass G type stars. Theyre similar enough to our sun, but can last upt o 30% longer giving intelligent life more time to evolve.
The question is, how is this first lifeform got created (the transformation from a nonliving thing to a living organism). And how this lifeform knows from the very beginning that it also *has to* reproduce, to not just die out. It does not know the concept of death, since it is the first one in existence. Just from this problem alone, i am sure we are unique in the whole Universe.
ok 1. 'first lifeform' we don't know probably just chemistry 2. 'it also has to reproduce', It does not know the concept of death 'first lifeform' can reproduce naturally just by following the laws of chemistry and physics. no need to have any concept for reproducing or will to reproduce. the death is the same.
@@vask3863 RU-vid is disgusting as usual removing comments for no reason. 1. We don't know how 1st lifeform was created. Probably just chemistry. 2. The reproducing can occur naturally just by following the laws of chemistry. No need to have a concept or will.
I will always hold the basic opinion that based on sheer number or stars and planets (Trillons of Galaxies) in all of the observerable universe there is other life out there. But, with that said what they are and various kinds that is the bigger question. If you want to use humans as intelligence as your base line, which I think is very questionable, but never the less. If that is your base line for intelligence life in our observerable universe, I do not know. But, if we don't try to figure it out then it is called giving up. I guarantee answers are to be found but it takes a very long, long time but there are many answers to found out there, guaranteed!
A few things to consider. Evolution requires change. A static planet I don't believe is sufficient to evolve complex life. So, this brings up the question of how many exoplanets in the Universe are in the "correct" range from their sun, have a tilt, have a satellite (i.e. moon) and experience catastrophic events? My guess is about a few thousand in the entire Universe. A very small number.
But you can't be sure we are the only intelligent beings on your timeline. Numerous civilizations might have come and gone and we'd see no sign of them after a billion years. When that 900 million year mark comes a civilization would probably not know we had existed.
I have always hoped life would be common in the Universe but there really wasn't much hard science to prove it either way...lot's of life or none? This new look at the statistical likelihood of life forming and evolving gives me some much needed hope, great vid.
A part of me says that life may not be as common as would like to think. The more we discover, the more we find that the Universe is an incredibly hostile place.
Something I've been thinking for a while too, is that we might be late in the game because of odds. There's the period called "the boring billion", where not much seems to happen, then suddenly something stirs the soup. Maybe things could go either much quicker or much slower, depending on geological events taking place or just a lucky microbial anomaly happening at a different moment.
Thank you for another solid analysis. The only factor that I didn't hear mentioned, but may still influence the result, apart from the Earth, is that there are likely planets out there with much longer 'life spans' than ours.
If the big bang theory is correct and everything was condensed into a singularity, would the contents of that singularity become correlated/entangled itself? Inflation occurs and stretches every wave potential into the fabric of reality? If that were the case, or even if reality is an emergent property from those interactions, wouldn't that render the speed of light to only the speed of light?
A relatively recent study has proven that nucleotides could form in ocean spray, and subsequently join together under certain conditions. I'll hunt down the paper.
I think we've grossly underestimated the difficulty in sentient life arising. Many science-nerds want life to be out there, and that has influenced/biased our thinking. It does freak me out that it has taken the entire life of the universe so far, for radio-communicating life to arise on this planet. If we don't see simple, independent life on the other plants of our solar system, I think the "life is not fussy" argument is probably wrong.
The most compelling explanation of the Fermi Paradox is that we are the oldest extant civilization in the galaxy (i.e. we're the first that is still surviving and possibly just the first). The universe is young. It has taken 1/3 the age of the universe for Earth to go from formation to hosting a civilization. The overwhelming bulk of the elements more complex than H or He that eventually collapsed to form the solar system were generated by stars that exploded half or more than half the age of the universe ago. The concentration of higher elements increases over time(I dislike using metallicity for this). It will have have initially been too low for the chemistry necessary for life. We don't know how long it took for these concentrations to grow high enough for complex life to be a possibility. The first possible abiogenesis is less than 13.8 GYA, but the elemental concentrations likely crossed that line somewhere between say 13 GYA and 7 GYA. The reason I don't like to use metallicity is that supernovae don't necessarily create all of the elements needed for complex life/civilization, or not in sufficient abundance. Some of those elements (I hypothesize) are primarily generated in kilo-nova explosions from the collision of neutron stars. Those take much longer, and produce less material than supernovae. They require binary systems with two stars in the correct size range to create neutron stars, and once they live their main sequence lives it takes a very long time for them to spiral down towards each other before they collide. The requirement for a sufficient number of kilo-nova explosions to seed the interstellar cloud with enough of certain necessary elements pushes the early bound of possible life further from the beginning. Also, the earliest minimum-necessary concentrations of heavier elements would be in regions of the galaxy that are much more active, and likely much more prone to planet-sterilizing events over the course of the billions of years that are presumably necessary to go from proto-planet to civilization. Those systems likely do not have had the luxury of the amount of time Earth has had to allow a civilization to develop. Per the video, Earth has a habitable period of 5 to 6 billion years and it took us 4 billion years to generate a civilization. That's a very large fraction of the time available. If the time to develop a civilization is typically only a fraction longer than it took us, or there are few planets with such a long period of stable habitability, then we may well be the first.
As a computer scientist, Giga Years Ago has to be one of my favourite units, really puts this in a more relatable way for me. Or rather shows me how incredibly long ago that is, truly fascinating how a simple change of wording can hijack that part of my brain that's been trained to deal with these numbers in apparently a very particular way :D
I find the metric system a good way to the tell kids about age. Just take a 2 m measuring tape. Each mm represents a year, 10 mm may be the Childs age - mine is 75 mm. And Jesus was born just after the end of tape (well maybe) - and if you look 63 kilometers the same way, that's where the dinosaurs went extinct !! (Ok not the birds) and about 4700 km away the earth was born !! Distance can be thought the same way - but 1 mm to 1 km creates much to big items a golf ball is better there. If a golf ball is the earth, the sun is 50,5 m away and be nearly 1/2 m wide (47 cm) and the nearest star would be 13.570 km away WOW. !!
Here’s the best part: it only needs to happen once. With sufficient advances in space industry and habitats, most any Star with enough junk around it can host a civilization. Obviously, the best-behaved and longest-lived ones are most desirable, just like land on Earth.
Very inspiring, so the question that popped in my head was: how does the condition of the planet influence the speed of evolution? Maybe because we have a moon and a Jupiter we get less asteroids. Our orbit gives a large habital zone all year etc. If conditions were different than maybe life would have had more obstacles to overcome and evolution would take longer. Maybe too long to get to technological life and there are lots to of planets with extremofile micro organisms.
Another very interesting video-- it's always nice to see you taking a quantitative, Bayesian approach to updating your beliefs based on new evidence! I would use caution when putting so much stock in these results though; the hypothetical dates of life's first and last appearance on Earth are in constant flux, and the publications in the description do not represent proof (nor do they claim to). I think it would also be wise to specify that the odds ratios you provide assume that the Sun's increasing brightness over the next several billion years is what would limit the advent of intelligent civilizations on other planets. However, there is another theory called the "Gaian bottleneck" which supposes that planets like Earth start out habitable, but their continued habitability is contingent on simple life arising and altering its environment, similar to how life on Earth has done. The novel "Death's End" by Liu Cixin even mentions a similar notion near the beginning, though it takes the idea in a very different direction when exploring the Fermi paradox. I will try to summarize the Gaian bottleneck as I understand it: in the absence of life, an Earthlike planet's habitability may quickly deteriorate, leaving a harsh environment for any life that evolves later on. This "late life" might then: (1) need to (unconsciously) spend additional time and resources improving the conditions around it, leaving much less time for intelligence to arise; (2) keep conditions from getting worse but also not make them better, making the planet unsuitable for the evolution of complex life; or (3) be unable to stop the deterioration and go completely dormant or extinct. The advent of intelligent life like ourselves would then depend sensitively on when simple life first arises, perhaps enough to explain a mere 200Mya delay, and the remaining habitable time after today would cease to be a factor. Obviously the number of possible factors and caveats involved here mean that this hypothesis does not lend itself so readily to the clear, quantitative approach that you are so effective at employing, but I think it's still worth considering.
What makes a big difference here is that there is strong evidence that the precursors of life are very common throughout space within space clouds. Combine that with where microbial life can not just live, but thrive, where we find life super deep in the Earth's crust, through all layers of the ocean, within all layers of the atmosphere including extremely high altitudes and being blown some distance into space while still alive, from the hottest Earth climates to the coldest, from very base to very acidic environments, from the driest to the wettest, etc. This means that the probability of microbial life is extremely high and we will likely find some on Mars, the Moon, Venus, Mercury, the moons of Saturn and Jupiter, etc. The bigger question will be whether any of this microbial life we find on other planets and moons will have evolved past some extremely primitive form. Clearly we see no signs of like like Earth has on the other planets and moons.
Even if high functioning, technological species are exceedingly rare, the potential offered by a universe full of even the most basic life forms is unfathomable.
Really superb video. It's my first time watching content from you and the way that you structured this showed that you're not only familiar with the scientific process but with scientific writing too. I am curious, in this video you presented the idea that life on earth could have started remarkably early. There is an argument for the fermi paradox that I personally believe, that life on earth is not a rare occurrence per se, but an early occurrence. The idea posits that earth formed cosmologically very soon after the last generation of stars went supernova, which deposited heavier elements throughout the universe, which are essential for life on earth. Then with the idea in this video of life forming on earth basically as soon as it could, earth could be one of the first if not the first planet that harbours life. Then, as the universe gets older, life will become much more common than it is today. Did you have any thoughts about this hypothesis?
