Why We Might Be Alone in the Universe

Why We Might Be Alone in the Universe

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It’s so crazy that I just happen to be in
one of the rare places in our universe where I don’t instantly asphyxiate or freeze or
vaporize or dehydrate. … Just lucky I guess. Actually, it turns out that our very privileged
perspective on the universe from Earth’s comfortable biosphere may tell us a lot about our reality. And perhaps resolves the Fermi Paradox. It shouldn’t be surprising that we live
on a planet that can support our existence, in a universe that can produce such planets. The anthropic principle tells us that we shouldn’t
expect to find ourselves in some random corner of the multiverse – there’s an observer
bias. In upcoming episodes we’ll be exploring
this principle and its two main versions – the strong and the weak anthropic principles. The strong anthropic principle tells us that
an observed universe must be able to produce observers – and we’ll get to the implications
of that soon – including the contentious idea that this predicts the existence of universes
beyond our own. But today we’re going to focus on the weak
anthropic principle, although it’s anything but weak. It says that we must find ourselves in a part
of the universe capable of supporting us. For example, in a planetary biosphere rather
than floating in the void between the galaxies. This may seems tautological, but accounting
for this observer selection bias is important to understanding why the universe looks the
way it does from our perspective. And the weak anthropic principle is much more
useful than that. When combined with the apparent absence of
alien civilizations, it may tell us that intelligent life is incredibly rare in our universe. To get to this, let’s think about what it
means to be an intelligent observer. Your mental experience of thinking about these
questions … exists. It’s happening right now. Your type of mental experience – your type
of being – could be incredibly rare – even unique – and only be possible in very unusual
environments. But you’re having that experience – you ARE
that experience. So no matter how rare these you-supporting
environments really are – by definition you’re in one. The weak anthropic principle places no limit
on how rare those you-supporting environments are. For example, if there’s only one life-bearing
planet in the galaxy, or in the universe, you’re going to be on it. The rare earth hypothesis posits exactly
this – that a range of factors made Earth exceptionally unusual and uniquely able to
produce intelligent life. This hypothesis was inspired by some striking
observations about our home planet, which I’ll get to – but also by one other piece
of evidence. Or, rather, a lack thereof – the fact that
we see no evidence for aliens. The Fermi Paradox notes the apparent contradiction
between the massive abundance of potential opportunities for technical life to have emerged
and spread through our galaxy and the apparent lack of galactic civilizations. Now, we’ve talked about the Fermi Paradox before,
and some potential solutions. But let’s consider the possibility that
it is exactly how it seems – technological civilizations are exceedingly rare – and maybe
that’s because Earth is an exceedingly rare planet. The solution to the Fermi paradox is often
expressed in terms of one or more great filters – extremely difficult or unlikely steps in
the development from barren planet to visible technological civilization. Such a filter might be after our own stage
of development – climate change, nuclear obliteration, whatever – still waiting out there to wipe us out. But the Rare Earth hypothesis is a little
more optimistic – it states that planets capable of spawning civilizations even at our own
level are very rare. The idea was named and brought to popular
attention in the book by Peter Ward and Robert Brownlee in 2000. It highlights a series of remarkable qualities
of planet Earth that may have been needed for life and intelligence to arise here. Let’s take a look at them. Actually, let’s start by something that
is NOT rare about the Earth. Earth-like planets are common. And by Earth-like I mean rocky planets about the
size of the Earth in orbit around stars very similar to the Sun at the right distance to sustain
liquid water on their surface – in the so-called habitable or Goldilocks zone. The Kepler mission has revealed there should
be 10 billion or so in our galaxy – 40 billion if we permit other star types. So, billions of potential starting points for
life in the Milky Way alone, even if we restrict ourselves to boring old carbon-based water-loving
planet life. That’s billions of planets stewing for billions
of years – if only one civilization had a tiny head start on us then it could have colonized
the galaxy by now. Unless Earth has special qualities that mean
true Earth-like planets are much rarer. Let’s think about what Earth’s has got
that seems critical for life and that could be unique. If we see that even one other planet has some
life-critical quality, then we know that that quality could be relatively common. But if we’ve only ever seen that quality
on Earth then it could be hugely uncommon – and the weak anthropic principle says it’s
still not surprising for us to find ourselves on one of the very few planets with that quality. We’ll start by comparing planets of our
solar system, because our ability to probe extra-solar planets is still in its infancy. Broadly, Earth has two qualities not shared
by the other rocky planets in our solar system: 1) it has a very dynamic interior and 2) a
very large moon. Earth’s solid iron inner core spins suspended
in a molten metal outer core, and this motion generates a powerful magnetic field that protects
Earth from dangerous space radiation and solar storms. Above Earth’s core is a solid mantle which
still flows due to its heat. This drives plate tectonics on the surface
– plates of Earth’s crust float around and are periodic drawn back into the mantle, or
subducted. This results in shifting connections between
ecosystems. And that may have been a critical driver of evolution,
promoting biodiversity. The periodic subduction of tectonic plates
recycles nutrients from the crust into the mantle and then back into the atmosphere through
volcanic activity. Without this biogeochemical cycle, many life-critical
elements may have been lost to the biosphere long ago. So Earth’s dynamic interior seems to be
life-critical in multiple ways. By comparison, Mars is tectonically dead and
Venus is at best tectonically weak – certainly neither have protective geomagnetic fields. We don’t know whether tectonic activity
is rare in exoplanets, but it may be. Which brings us to the moon. Earth’s moon is ridiculously gigantic – no
other rocky planet in our system has anything like it. Its size and also its composition and orbit
suggest that it formed when a Mars-ish sized planet collided with the Earth right after its
formation. The debris thrown up during this collision
became our moon. Now, this could be an incredibly rare scenario,
even galaxy-wide. It may also be that our moon and the event
that formed it was critical to the development of life. That impact likely gave Earth its rapid rotation
rate – with short nights essential for photosynthesis, and also its axial tilt. A moderate tilt could be critical if seasons
are an important driver of evolution. Too large a tilt and seasons become too extreme
for life to thrive. Earth’s tilt seems just right – perhaps
even rare. That impact may even have kickstarted Earth’s
extreme tectonic activity by fragmenting Earth’s early crust into moving plates. And the moon’s later tidal influence may
also be an important factor in enhancing ongoing tectonic activity. And a final possible result of our weirdly
large moon is that it enabled the first appearance of life. It may have enabled abiogenesis. One hypothesis for the first formation of
life is that it evolved in tidal pools, with complex chemicals and eventually proto-cells
emerging as a primordial soup sloshed in these pools, baking in the sun. Without a large moon tides are half the size, so fewer tidal pools. More recently, alternative hypotheses for
the location of abiogenesis have gained favor – particularly geothermal vents on the ocean
floor. OK, so Earth is weirdly dynamic and has a
weirdly giant moon, but there’s more. Our entire planetary system is pretty weird. We’ve only figured this out as the Kepler
mission wrapped up its census of other planetary systems. Our solar system has a huge range of planet
properties – from the tiny rocky Mercury to the gigantic gaseous Jupiter and Saturn. In contrast, the planets of most other systems
tend to be all around the same size as each other and planets as large as Jupiter and
Saturn are pretty rare – only around 10% of systems. And yet Jupiter in particular was probably
pretty important for the development of life. That planet acts like a gigantic gravitational
vacuum cleaner, absorbing a lot of the debris left over from the formation of the solar
system. It no doubt sucked up many comets and asteroids
would otherwise have hit the Earth. If we’d had a significantly higher rate
of mass-extinction-level impacts, perhaps evolution would not have progressed so far. Perhaps life would have been wiped out entirely. There are a few other possible rare Earth factors – we
may have an unusually hospitable atmosphere and water content and may have been lucky in avoiding
various cosmic catastrophes like gamma ray bursts. But the final thing that may make Earth a cosmic
rarity is the path taken by evolution. Perhaps life is extremely common – or at least
extremely simple life is common. Perhaps the great filter is one or more extremely
improbable steps that happened in the evolutionary transition from single-cellular life to complex
life, or to intelligence. Just one example of this: the evolution of
the eukaryote cell. This seems to have been a freak evolutionary
incident, in which two much simpler cell types fused – one absorbing the other, perhaps in
a failed attempt at dinner. The absorbed cell became mitochondria, an
energy power house that allowed the new chimerical cell to massively increase its complexity,
ultimately leading to the first multicellular organisms. There are many factors that shaped Earth’s
formation and development – what if the Cambrian explosion had never happened, or the asteroid never wiped out the dinosaurs, or an extra asteroid wiped out our ancestors? There are lots of ways that it seems Earth
got lucky. The question raised by the rare earth hypothesis
is just how lucky were we? Many of Earth’s life-critical qualities
or development steps have not been seen elsewhere, nor do they seem to have happened more than once – at least yet. The weak anthropic principle allows that these
singular events were phenomenally unlikely – we simply can’t assign them larger probabilities
until we get more evidence – which ideally means seeing them happen more than once. It’s very possible that a combination of
extremely unlikely factors means it’s extremely rare for planets to spawn intelligence. The Fermi paradox surely has a solution, and
that solution may be that the galaxy is as empty as it looks. We find ourselves in the only place we could
be: gazing out from our rare earth into the untamed, unpopulated reaches of spacetime. We skipped comment responses last episode,
so today we’re covering two episodes – loop quantum gravity and time travel. Easy peasy. A few of you wondered if there’s a connection
between the loops of loop quantum gravity and the closed strings of string theory. The answer is not really. The strings of string theory have a somewhat
physical interpretation – the fact that they can hold energy and vibrate and exist in space. But the loops of LQG aren’t really physical at all. Which brings us to the most common question
– what actually ARE the loops of loop quantum gravity? Well, crudely, they’re a mathematical way
to describe the geometry of space – which means they aren’t in space, they sort of ARE space. Or at least familar 3-D space emerges in an
abstract way when we think about a network of these loops. But that doesn’t mean the loops are physical,
they’re just a way to parameterize the quantum-scale geometry of space. Where we transition from the abstract to the
physical is not at all clear, and, honestly, hurts my head. Dig into spin networks and spin foam if you
want a headache too. Serenity Receiver asked about the experiment to test Loop Quantum Gravity So LQG predicts that light of different wavelengths travels at very slightly different speeds. And this was NOT observed in the light from a
distant gamma ray burst, which presents a challenge for the theory. So why does LQG predict different speeds of
light? Well, if space is quantized on tiny scales, then
we expect the very shortest wavelengths of light to be slightly perturbed by these quantum
cells of space – sort of like traveling through cracked glass – they interact with the edges
and slow down. Wavelengths longer than this quantum scale
can ignore this fragmentation and so travel at normal speed. There were some good questions on the Typler
cylinder – that’s the infintiely long cylinder that you can travel around to end up back
where you started – in both time and space. Some One asks if a circle in 2 spatial dimensions
would allow for closed time like curves. Actually yes! I saw this in at least one paper. Time travel is easy in flatland. Troy Henry asked if a torus would serve as
an infinitely long cylinder – well the answer is, sadly, no. The cylinder has to literally go on forever
in both directions. At the beginning of the time travel episode
I invited future time travelers to show up on set. None of you did. But several of you got onto the comments to say
I forgot to post the address of the studio one year from now. But I have to ask – why did you wait until after
that episode to tell me that? Surely as time travelers you could have reminded
me in the loop quantum gravity comments the week before. I’m suspicious. Or maybe Stephen Hawking’s chronology projection
conjecture prohibits anyone from remembering to post addresses to time traveler parties. But Guy Frost has a better explanation – YouTube
won’t survive into the far future. I guess when it goes offline you can blame that
invitation.

100 thoughts on “Why We Might Be Alone in the Universe”

  1. After researching, reading, and watching the articles and medias. There is no life outside besides the planets and creatures. We are maybe alone because of galaxies colliding or dying

  2. How about the theory that we are far from alone but aliens just don't want to make any contact with us?
    They have observed us and concluded humans are an absolute bunch of assholes to be avoided at all costs.

  3. Fermi Paradox doesn't take in consider different life forms. Wy should life be carbon based? Or maybe life exist in 5 dimensional space ? We can only philosophize from earth perspective.

  4. There's a few things that I wonder when considering this.

    1. The exoplanets that we've discovered are far enough away that we are seeing, at least, only the light from several thousand light years (I think the closest Earth like planet is 1,120 light years away iirc.) It's possible that can't see life around Earth like exoplanets because of how far in the past we're seeing these objects.

    2. Because of this, I'd have to consider the age of these planets. While I can't find anything conclusive on how old any of these planets are, it could be possible that they are similar in age to Earth, therefore, they might have developed on a similar time scale. This would lead me to wonder if its possible that intelligent life on those planets would be around the same age as us and therefore they may well be around the same technological capabilities as us.

    3. We also have to look at how societies form and how they can actually prevent technological advancement. It is possible that an exoplanet that is the same age and developed on the same timescale, could produce intelligent life that has not advanced beyond a certain age due to things like religious influences. We always expect that intelligent life would always be more advanced than us, but it possible that said life could be around the same evolutionary point, but who's civilizations haven't developed as quickly as ours.

    I might be completely off base here, but its a thought.

  5. Hello, The ARK/Aederus Foundation Has Arrived To Say That You're Not Alone, But The More Evolved Species Have Just Hidden From You At The Moment, Although We Do Sometimes Visit, Albeit Rarely.

    If You Want To Communicate With The More Friendly Ones, Please Head To The ARECIBO Dish And Point Towards The Large Magellanic Cloud.

    There Are Passive Trade Routes There, And As Of Recently, They've Set Up Newer Rudimentary Starways And Trading Docks, Waiting For Human Spacecraft, Although They've Only Learned Latin At The Moment, As English Is Too Hard For Them To Learn In A Decent Amount Of Time.

  6. I think there's a cycle where civilizations need a power source which subsequently ends up threatening their civilization and they have two pathways forward: Go extinct or develop technology advanced enough to control a planet's ecosystem.

    More civilizations probably fail than succeed, but would those civilizations want to make contact with a lesser advanced species? Maybe not. Maybe so. We've only had the means to reach out from our planet for like 90 years.

  7. Life might seem rare from our perspective but we remain yet ignorant of what we dont know. There could be other than carbon based life forms and paths along our evolution seem important since we cannot imagine any other paths. The theory completely ignores that.

  8. Also, speed of evolution is a factor. Just a little slower and the ageing sun would have made earth uninhabitable to life before we evolved. It took something like 4bn years of evolution to produce humans and we only have 0.5bn years or so left before photo synthesis, and advanced life, ends.

  9. I disagree there’s other shit out there maybe not intelligent life but there’s life all we are is elements carbon H20 sulfur etc… Life on earth can survive in the -100 degree weathers of Antarctica all the way up to the infernal deserts that can be up to 150 degrees. Also withstanding deep sea pressures and tardigrades can survive in volcanos and outter space.

    I don’t understand why millions upon millions of stars that are much bigger and brighter, with unique characteristics our sun doesn’t have, couldn’t harbor life, every star has a Goldie lock zone I don’t think it’s too insane to think that 1 of billions of stars doesn’t have a mud ball like ours

  10. Humans: Are we alone?
    AGI: 01000111 01101001 01110110 01100101 00100000 01101001 01110100 00100000 01100001 00100000 01100110 01100101 01110111 00100000 01111001 01100101 01100001 01110010 01110011 00101110 00101110 00101110

  11. If Earth and the steps that have happened so that life can thrive on Earth is really that rare to the point to which everything in the night sky is basically window dressing then we might as well be living in a simulation.

  12. … and the fact that Hebrew when numbered and named has lots and lots and lots of "coincidences" – https://haimshore.files.wordpress.com/2014/02/haim-shore_coincidences-in-the-bible-and-in-biblical-hebrew_feb-2014.pdf

  13. Love these videos! I disagree, however, with a lot of these 'rare earth' type scenarios. All these factors are needed for OUR evolutionary tree. We shouldn't entirely bind ourselves to that notion.
    Life uh, uh, uhhh, find a way!

  14. Based on some reading such as Darwin on Trial, there is no hard evidence supporting theory of evolution. This episode seems to describe evolution as extremely unlikely.

  15. How can this be a sound theory when science abhors’1’ thing? If a finding can’t be duplicated in a lab by others, the finding is dismissed. ‘1’ of anything in nature is absurd. Sure, in theory, ‘something’ started something, unless it was multiple things coming together in the same event and some of those things clearly stuck. Has anyone considered maybe the reason we don’t see alien is because anyone who can go between the stars can also navigate time, so all technological savvy race goes back. The Fermi paradox needs to add temporal anomalies wiping people out or putting them out of our sphere of influence. Science has slowly minimized human by pushing us further from the center of the Universe, and yet this seems to put us right back at the beginning. Hubris much?

  16. There are more then 2 billion galaxies, there must be life of all kinds out there somewhere. Either its impossible to travel faster then the speed of light or their is no reason to or both. If you could make all the energy you want at no cost to the environment you live on, and you had powerful telescopes to view you dont need to travel a long distance to get to a place you can see and feel where you are.
    Another thing I never hear anyone say, may earth, our solar system, our galaxy is a boring place compared to the other Billions out there. think of it this way, if you could visit a place on earth would you go to Hawaii or the South Pole?

  17. Very misleading "computer model" about the formation of the moon. Moon rocks show the earth & moon are NOT related. Scientist don't how the moon exist in it's present state. There are lots of theories, but no cigars. PBS lives in denial concerning the overwhelming evidence of intelligent design.

  18. Basically its saying “between letters” that 8KM of poor people should be thankful that their existence even if it’s miserable because is very rare.

  19. A very stupid hypothesis. We cant see further, therefore we place that as a limit? Thats not scientific. And by the way, evolutions doesn’t need seasons. Evolución was shaped by seasons. Not your best episode

  20. I believe it is almost impossible to find another earth like planet. But I believe in aliens. There is science beyond our imagination. Aliens may not breathe oxygen. They could have had a different evolution.

  21. If we can prove multiverses and alternate universes, which we have. Then extiction is just an illusion. The dinosaurs didn't get wiped out. They simply moved on from this system.

  22. I am no scientist/astronomer/cosmologist guy.

    but, isn't the Fermi Paradox pretty wrong in thinking that we would see alien life if information only travels at the speed of light? Civilization for us roughly started about 12k years ago. Even if we were somehow giving off radio signals at that time, that's literally 1/10th of the Milky Way galaxy. That is a very very small area that's going nowhere fast still.

    Not to discredit the idea that we may actually be alone, just an observation.

  23. Many life forms are not at all dependent on the moon in any way in their current state. Extrapolating that to also cover "formation" is a bridge too far, however. Personally, I've always seen the Universe as a budding collection of spacetime where we level up on the Kardashev scale and colonize systems. There is no need to look for other life if the aim is to create it.

    Let's strap a Dyson sphere to the sun and put a thruster on it..

  24. oh god I hope that there are aliens out there that also feel existential anxiety and shiver at the thought that they are all alone in a giant dark empty place. It would be so funny if we finally meet each other and realize that now at least we are together in this large and empty universe to feel our existential anxiety for our inescapable demise in this giant void.

  25. Before I watch this…I just want to point out that the US government and multiple news sources had a video earlier 2019 that said we might not be alone…with video proof.

  26. There is plenty of evidence of extraterrestrial life on this planet. You cannot possibly miss it by doing research.

  27. Actually we're not alone, well in my opinion. There's life in different dimensions actual beings just like us but far more advanced then us in everything. Talking about through teaching, understanding life, technology, and so on. What we call "aliens" how you think they travel back and forth so fast in a blink of an eye.. theres portals and have technology to travel within it.

  28. Pluto also have a moon that is large relative to its own size. This means that large moon formation as a result from collision is not so rare.

  29. Genesis 1:26

    Then God said, “Let Us make man in Our image, according to Our likeness; and let them rule over the fish of the sea and over the birds of the sky and over the cattle and over all the earth, and over every creeping thing that creeps on the earth.”

  30. can you make avideo to tell
    us what is the mean of (we should measure to give result for the universe ) in quantom I mean …. if I measure and dont tell any one dose this the result for everyone exist

  31. we are not alone. like every country has its laws, maybe other civilizations need other type of life sustaining conditions to exist. maybe their periodic system of elements is completely different. maybe they eat diamonds. who knows. oh wait…we have those. well.. why ant can live his life without ever saying hello to me, am I so alien to him? or is he saying hello the whole time, I just can't hear him. firstly, we need to respect every being on this planet, then we can say we are ready to find intelligent beings on other planets.

  32. Maybe we are just a small bubble and live on the cell of another cell. Maybe we are a cancer that has found a way to transfer our disease faster and faster as we grow immune to whatever it is we are attacking.
    Maybe we are part of a bigger atom. Maybe we are not even real and we all are just spirits in our own hell.
    Or maybe there is a God and as we get closer to self destruction our maker will save us from ourselves.
    I mean think about it. We know nothing really. Because today there are over a hundred genders. For 50 years I was taught there are but 2.
    So as the genius people confuse the masses and try to confuse our youth in school each day, denying science of years ago and teaching this new nonsense why in Gods name would we believe anything you try to teach?
    Here is common sense truth.
    There are 2 genders. Male and female. Woman and man. Him and her. No matter what you do to your body to prove otherwise. There is sound science.

  33. Back at the time of undeveloped Sci-Tech that we believed we weren’t alone in the universe, since then there were more and more facts proved that we might be alone all the time…

    Sad

  34. I dont get too wrapped up in all this. There is a very high possibility that we will never be able to confirm life on other planets. There might have been a civilization 50 light years from here… 500 million, a billion or several billion years ago. There might be a flourishing civilization right now a billion light years from here… but there is no way we would ever know. With the distances so unbelievably huge and the limitations imposed by the speed of light… I think it will remain a huge question mark for at least the foreseeable future.

  35. Plot Twist. The so called Aliens people swear to have seen are in reality future humans that came from the future to study us because we are indeed alone in the universe.

  36. What about the Young Universe Hypothesis? I like to think that Earth isn't necessarily 'rare', but that our universe is more or less too young to have spawned enough intelligent civilizations for us to come into contact with. We may not be the only life in the universe, but until the universe gets old enough to play host to multiple intelligent civilizations in close proximity to one another we most certainly are alone. Hell, for all we know we could be among the first life to arise in the universe.

  37. What if all the advanced civilizations just escaped the simulation and are off having fun up in the metaverse?

  38. People who think we are unique in the universe have little sense or are narcissistic or think humans are sooooooooooooo important. Get over yourselves. We know VERY little about the universe and the next alien encounter could be right around the corner. Imagine the culture shock and rethinking of major religions when that happens. Several million or billion alien civilizations could rise and fall without any of them knowing the other existed. The distance between the stars and the time frame when one civilization becomes space faring and dies out before another one close by does the same means the chance of bumping into one another is very remote.

  39. Counterpoint: the probability of you being born is 1 in 400-550 trillion, give or take. You are exceptionally unlikely to have been born. And yet there have been 7 billion of you who have been and counting. This is obviously metaphorical and my command of math is not strong. But unlikely things happen on a distressingly regular basis.

    This is a medicore earth theorist just dropping a thought.

  40. There is no possibility of time travel because you would have to replace all the transactions of energy that occurred during the spans of time. There is only one time it is the now.

  41. Let's assume we are not special in any way, here on our planet. We need an abundance of elements created by supernovae to evolve so we could not have come much earlier in time. If other life in our galaxy is as common as us and evolves much as we do, then looking for life results in us looking back in time as when any EM radiation from that life will not arrive until well into our future.

  42. More and more geologic evidence suggests that the extinction event at the end of mesozoic era was caused flood basalt activity (Deccan Traps), Chicxulub impact was only the cherry-on-top. Back when I studied goegraphy it was only an exotic idea, only the permian event's main trigger was named tectonic activity with confidence. Also, let's not forget about snowball earth among the extremely rare evolution enhancing effects, which is also turning into a solid theory in the last 15 years.

  43. We have listened to the results showing the universe is flat. A paper published today in Nature Astronomy claims to have reanalyzed old data and found the universe is closed with 99% confidence. Really? Would Matt please comment? paper: https://www.nature.com/articles/s41550-019-0906-9

  44. Perhaps intelligent life does exist but they are incapable of actualizing due to their body type like, say dolphins. Their behavior remind me of human tribes but they have no way to manipulate the world around them like we do with our hands and so are evolutionarily stunted.

  45. There is already proof that objects are seen in our skies and oceans that can outmaneuver anything we can produce. Even admitted by the government. Why is other life in this enormous universe even a question?

  46. We don't really understand quantum physics in any sensible kind of way, we don't know what 'dark matter/energy' is, we haven't even scratched the surface of discovering what's in our own oceans or brain. Saying there is no life out there except for us or that intelligent life is rare is just a 'guess' at this point, and quite frankly given how much 'we still don't know' about our own universe it's a terrible guess. Grab a table spoon from your kitchen drawer, then go out to any ocean on the planet and fill your table spoon with ocean water. Do you see any life in your table spoon? No? Well, then I guess there must be no life in the ocean or life in the ocean must be really rare based on your observation. We know absolutely nothing about life – or lack thereof – on other habitable planets because we haven't observed them up close let alone our own oceanic moons right in our back yard! In terms of radio signals, perhaps we're on the wrong channel or using a sort of technology that hasn't been invented yet or maybe we're the first ones?!

    Great video, and it's obviously important to discuss differing theories, principles, and ideas. Too many people in the comments have already drawn premature conclusions based on 'guesswork'; remember we haven't observed habitable planets 'up close,' but we do know they are plentiful! They're just too far away.

    In terms of intelligent life, we really have nothing to compare 'our intelligence' too; save for dolphins, or octopus. It might just be, that our intelligence isn't even that intelligent at all compared to other organisms in the Universe and I find it quite hubristic of us to assume that we will be able to communicate with a more intelligent organism or other extraterrestrial organism in general . We can't even communicate 'effectively' with some of our more intelligent species right here on earth. Not only that, but we may be surrounded with intelligent life or complex organisms in our galaxy, but we're just oblivious to them all the while they see us, but are non interested in humans in the same direction that we (most) humans aren't interested in ants. Think about it, ants are a super organism, they dominate their domain, they are intelligent (in their own way) and extremely good at what they do "in their realm; their level of existence. All the while being utterly oblivious to our level of existence/realm and have absolutely no way of accessing or even comprehending our way of life. How do we communicate 'the internet' or the way a 'beer tastes' to an ant? It's impossible. It just might be that it's also impossible for us to access the realm of a highly intelligent super organism that is above us – or somehow exists in and comprehends the world of 4th dimensional space – due to the limits of the human brain.

  47. Isn't the rare eukaryotes theory pretty much debunked? Mitochondria and chloroplast actually trace their beginnings to multiple separate jumps in our past, so if it was possible several times on Earth why not elsewhere? Chloroplasts are especially weird, they not only jumped directly to plant symbiosis, some plants have actually symbiotic plants inside which contain all chloroplast, making them double eukaryotes essentially…

  48. Wasn’t it Fermi who said, essentially, we are either alone in the universe or we are not. Both are equally terrifying. I tend to take the more…optimistic view. Both are equally awesome. If we are the only civilization in the universe we will certainly not be the last. If we happened once the odds of us happening again are counter intuitively a little better.

    There is only consciousness. Oblivion is untrue. There can only be I. I am here. I perceive while being perceived. How Strange it is to be anything at all.

    We live during the era of Star Birth. When the follow on civilizations come in a few trillion years they will never know we existed and if they theorized that there was an Epoc of Stellae birth and death, we can forgive them for thinking that life was impossible during this time.

    When we die the next sun we see will be a red dwarf.

  49. If life existed in another planet it is very unlikely they would look like us maybe bacteria as a base but unlikely to develop a brain
    so intelligent life is 0.000000000000000000001% chance.

  50. Bs. So with how our government works and kills anyone with unknown knowledge. And seeing how anything identified gets fucking kidnapped. You really think aliens would even come to earth. Fear exists everywhere. Their fear of dying and being used as test subject limit their probability of coming to “visit” .-. Earth is ass and disgusting. Aliens should just blast it.

  51. Whatever we THINK can happen is POSSIBLE to happen because we can THINK that it can.
    If we think that mice can survive in the vacuum of space, then somewhere in the Universe, it is possible. The Universe would not allow us to think it if we weren't a product of it. 😛

  52. well we're just going through our great filter, we could call it donald trump, making sure we don't make it through climate change, there problem solved, eat this fermi paradox!

  53. Billions x billions of galaxies with trillions x trillions of stars… so laws of average don't apply anymore? Someone please slap him!!

  54. this is ludicrous nine cents, and while I like this guy, this video is a complete waste of time. we already have several high-ranking government officials admitting we have ongoing contact, so please take the tired tripe out to the trash. let’s reiterate, the idea that we are alone in the universe is utterly ridiculous, And unbelievably arrogant

  55. I think the fact that no civilization have bothered to take over the galaxy yet has nothing to do with whether or not they exist, but whether or not interstellar space-travel is even possible on large scale. If anything it disproves time travel, worm holes, warp drives etc.

    Another thing i wanna point out is that uncommon does not equal alone. Yes life can be extremely uncommon but the chance that there is only 1 instance of a planet with life is highly unlikely. That's because everything in the universe is created from the same laws of physics. Two galaxies, regardless of distance or whether or not they even lay within the same cosmic horizon, will appear the same way, and they will contain similar solar systems with similar planets. Planets with similar rings and similar asteroids etc. There is no unique place in the universe, according to the cosmological principle. This means that you should think of life instances not as a number, but as a density. The odds might be near 0, but the odds of hitting 1 instance with those near 0 odds is border line impossible.

  56. Let's say that only one in a trillion planets identical to Earth have intelligent life on them. That means there would be many many thousands or millions or billions of intelligent-life-holding planets in the universe, but they're just so far apart, we might as well be alone. The observable universe is HUUUUUGE.

  57. Just saw the post of a *looped universe*…

    Keep guessing, I will enjoy my life not worrying about the one thing that I can be sure of…

    If I can't see proof, it's just not true…
    Yes the hypocrisy of science and the scientific cults..

  58. Whenever anyone comes up with an explanation based on we are unique, it eventually gets debunked. So this is also unlikely I think.

  59. There are many species of life on this planet in the most inhospitable areas. To say seasons matter doesn't take these species in to account. These creature are not effected by seasons at all.

    We would not have mammals if it weren't for the mass extinction events in earths past. Life is inevatable in our universe. Intelligent life needs a reason to evolve. Without mass extinctions life would not need to evolve beyond it's most efficient state.

    Take fish for example. Without mass extinctions there would be no reason for life to evolve to fill the voids in the rest of the world and fish wouldn't of evolved. Life would of settled in with no real rush to change. Look at sharks. Their evolution has slowed to a crawl because they are perfectly efficient for their environment.

    As for, if alien life evolved before humans that life would colonize the galaxy. What your not taking into account are several factors.

    1. They could have destroyed themselve just like we are right now.

    2. Being more advanced due to evolving earlier means they would have had more time to learn spreading like a virus isn't the most intelligent method for growing. They could of discovered better recycling methods. There are many reasons they don't need to spread.

    That bias you mentioned about our perspective is clouding your mind. Do not place human ideas, behaviour or concepts on unknown life. That life will prove you wrong.

    3. Being higher on the advanced civilization tier list than us, means they can do what they want and we wouldn't even notice. Our detection methods would not be enough. What if they don't want us to see them? Don't presume motives of life we haven't met.

    It's foolish to say we're alone, especially when we can't get off this planet. Sending drones is a slow method and Voyager just reached interstellar space. Presumeing there is no life out there is like declaring an atom doesn't exist, because you can't see it with the naked eye. It's there else nothing would exist.

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