Why We Might Be Alone in the Universe

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    Why does it appear, that humanity is the lone intelligence in the universe? The answer might be that planet Earth is more unique than we've previously assumed. The rare earth hypothesis posits exactly this - that a range of factors made Earth exceptionally unusual and uniquely able to produce intelligent life.
    In upcoming episodes we’ll be exploring the anthropic principle and its two main versions - the strong and the weak anthropic principles. The strong anthropic principle tells us that the observed universe must be able to produce observers - including the contentious idea that this predicts the existence of universes beyond our own. But in today's episode we’re going to focus on the weak anthropic principle. 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 why intelligent life is incredibly rare in our universe.
    Hosted by Matt O'Dowd
    Written by Matt O'Dowd
    Graphics by Leonardo Scholzer & Adriano Leal
    Directed by: Andrew Kornhaber
    Executive Producers: Eric Brown & Andrew Kornhaber
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    Published on 9 days ago


    1. PBS Space Time

      Hey Everyone! So this is our first episode released in 4K. Hope you enjoy the upgrade.

      1. Zoltan Matey

        the universe is big enough to have repeating type of evolutions arrise on different places

      2. Element Zero

        *Brigham richins* Soooo close to being right. Buuuuuut wrong. It did eject radiation but in axis directions, up and down, creating bubbles above and below the galactic core. NOT throughout the galaxy. It didn’t spread through the whole galaxy, it didn’t trigger any technological explosion in our history or potentially wipe species out. Radiation is detectable and slowly decays, if our planet was exposed to a MASSIVE dose around the same time that Sagittarius A-Star burped and irradiated us, we would have corresponding data which matched the event to radioactive decay here on earth.

      3. Matt Roberts

        Do you have tweeter I have something to show you

      4. Callum Booth

        @Valentino Popa right you are!!!!

      5. Abdullah Shams

        Awesome Upgrade

    2. Shane Mackinnon

      Hello fellow 👽 frens. Cracks are showing in the matrix. Big ones. “When the human race learns to read the language of symbolism, a great veil will fall from the eyes of men. They shall then know truth and, more than that, they shall realize that from the beginning truth has been in the world unrecognized, save by a small but gradually increasing number appointed by the Lords of the Dawn as ministers to the needs of human creatures struggling to regain their consciousness of divinity.” 👁‍🗨👁‍🗨 "Eyes Open, No Fear"

    3. CornerTalker

      Raised on Star Trek and Star Wars, I WANTED to believe that varied assortment of civilizations around every corner of the galaxy, but the more I read and think, the more I believe in the Rare Earth Hypothesis.

    4. RisingDawn

      Please for a moment, step back and consider how absurd the naturalistic worldview is. Naturally, people don't want God in their thinking. They want to be the god of their own lives. But you will never find fulfilment if you continue in your rebellion against your Maker. He is rich in mercy and compassion to all who turn to Him, no matter what you might have done. Jesus Christ, the eternal Son of God has come that you might have life. This is the mystery of God... God was manifest in the flesh and dwelt among us. He gave His life for us that we might gain eternal life. The work God now requires of you and me is to believe in the One who was sent. Come to Jesus Christ, the One whom you have most likely blasphemed time and time again. Come to Him in humility and faith, and you will find truth and the promises of eternal life.

    5. easyguitarsongs

      "I happen to be in this rare place where I don't vaporize, asphyxiate etc.." I think u got that backwards... you were not dropped on this rare planet from some external location that picked the right planet for you. You emerged out of the planet like an apple emerges from an apple tree. The apple can't say "well, what a coincidence that I just happened to be attached to a tree that gives me all the nutrients that I need, doesn't devour me before I bloom, and doesn't grow upside down so I can get sunlight and air to grow." u evolved to breath oxygen because ummm.. surprise.. oxygen happens to be in the atmosphere of where u evolved. Right? You are made of 70% water. Why? because the planet you evolved on is 70% water? We are not a separate entity from out planet. We are part of this earth. If we are removed from this earth, we will wither away and die like a fish out of water.

    6. sonnydey

      Na, it's more like why are we alone in our corner of our galaxy few 100 light-years around us? And a galaxy domination is just too hard.

    7. Danny Lackie

      Such a load of complete horse pucky!! Obviously this channel and it's sponsors are on the payroll. We are NOT alone and never have been. Don't believe me, fine, just watch Dr. Steven Greer or even better Emery Smith who still actively works on black budget programs for Uncle Sam.

    8. K君 harekelas

      Life on other planet may not need to be big, even if they are big, they may not need to be intelligent, even if they are intelligent, they may not need to be curious enough to explore the universe. I believe life is common in the universe, but life like human beings may only be us.

    9. Troll Master

      Network of string loops = Aether

    10. Bob Dole

      Extremely unlikely, considering we have never left our solar system.

    11. Wesley Grace

      I just wanna know how do you tilt a sphere?

    12. Seamus Howling

      Lies! PBS is the latest causality due to filthy Russians!!!1

    13. r m

      The greatest scientists is our own real god. If everyone realized just how unique and special we are maybe all life would have infinite value. I'm smart enough to say that there is something or one Jesus who is my creator and so much smarter than I can even comprehend. Wow just wow.

    14. LtCol Pulaski

      @11:54 Not just "intelligence" but intelligence in a life-form with binocular vision, with the ability to move over most of the planet surface, land as well as water, and with the capability to grasp objects and with the fine motor skills to manipulate them. In other words it doesn't matter how intelligent elephants and dolphins are or become, neither are ever going to be capable of inventing silicon chips and building particle accelerators, telescopes and rockets. In fact I don't see how either could even invent the wheel, so without a significant and also likely extremely improbable set of skills and qualities, intelligent life is going be unable to communicate its existence to us, and would be unaware that we are looking for it. Imagine the world 5 million years ago - teeming with life, but no complex machines, and no understanding of the universe. There may be thousands, or millions, of such planets in the Milky Way, teeming with intelligent life, but without the evolution of a sapient monkey, there isn't going to be anything in the universe for us to communicate WITH.

    15. Abel Valdez

      Ah so Jupiter is like Earths bouncer from weirdos and murderers

    16. Nikolas Honnef

      Thanks Jupiter!

    17. Clyde Frog

      Imagine being so narrow minded that you think the only way to live is exactly like we do. Maybe aliens dont need air or water and breathe gas fumes and drink liquid mercury??

    18. Frank Zappa

      "The Universe is pretty big place. If it's just us, seems like an awful waste of space." - Carl Sagan.

      1. Frank Zappa

        @Ethan Steel ". . . and ?" - Me

      2. Ethan Steel

        @Frank Zappa "Continuously quoting others get irirating fast. And is pointless." - Ethan Steel

      3. Frank Zappa

        @Ethan Steel “I'm sure the universe is full of intelligent life. It's just been too intelligent to come here.” ― Arthur C. Clarke

      4. Ethan Steel

        @Frank Zappa Or at least some sort of evidence.

    19. Mike G.

      The only life out there is Ultra Terrestrial. We are alone in this space/time. 👽

    20. John Maelius

      No matter how much they try to push this.. I will never believe we are the only intelligent beings here

    21. BFjordsman

      Is this SFIA for normies?

    22. ChrisBrengel

      Great video, thanks. Please be careful with the term "intelligent life". You probably mean "technological life". Dolphins are intelligent but they can't make telescopes or radio transmitters.

    23. NS C

      Narrow definitions of intelligence and life when universe is so vast and mysterious.

    24. patchris07

      Or or or we are alone because their is a God. Just throwing that out there to infuriate the Atheist and Secular crowd. Because you know the “G” word riles you up into immature closed minded insult spewing machines. LMAO!

    25. Misterlikeseverythin

      I think the great filter must be the evolution of intelligent life. It took billions of years for eukaryotes to evolve and out of all the millions (maybe billions) of species over the billions of years exactly, 1 speciest evolved advanced intelligence - humans. I would put chances of species like humans evolving in about 1 in a billion at best. So our Galaxy is basically full of planets that have prokaryotic cells, some that have eukaryotic cells, even fewer that have algee-like creatures with photosynthesis-like reactions, a lot fewer planets with complex multi-cellular organisms and fewer planets on which these organisms evolved intelligence rather than claws, teeth, size, camouflage, speed.

    26. MrDreihornn

      I now want to drill into the Moon and look into its centre

    27. Lya Naylo

      is that UFO 1 music in the background :D ?

    28. GEOindustries0

      Donald Brownlee, not Robert as stated.

    29. Al Rats

      The Rare Earth Hypothesis is clearly the most compelling "solution" to the so called "Fermi paradox". In fact, there never was a paradox to begin with. The fact that all life on Earth today share a common ancestor shows how rare it is for life to emerge and sustain itself long enough for intelligent life to develop. Even planets with only single celled organisms are probably extremely rare. Those who think there may be life elsewhere in our solar system are retarded in my opinion.

    30. Wario Andretti

      When did Peter dinklage start doing youtube

    31. PCFanatic LetsPlay

      Over the billions of years, there is certain to have been plenty of intelligent life on plenty of planets, but most likely never any life close enough to other life that can breach the vastness of space to come in contact... It's just very, very, very rare that two life supporting planets with intelligent life would exist close enough to come in contact, and actually exist at the same time. Mars could have had life before the time of Dinosaurs on Earth that died off and were obliterated from the surface of the planet millions of years before we even began to realize we weren't the center of the universe.

    32. James Gleeson

      There is intelligent life out there but they just flew past me. This means they don't really care to know me and I walk alone and enjoy here and now in the best way I can.

    33. Baigandine L

      They seem to tend to assume this other complex life has an interest in colonizing the galaxy.

    34. Thomas Busse

      wait a second, and I mean this seriously - suppose we were a universe simulation from light energy beings and the Earth was constructed by giants and placed in a zone where intelligent life could develop. The ancient megaliths that show advanced technology could be seen a sort of fine tuning - a whittling away of material to create a habitable Earth. The planet was constructed or at least refined. It explains so much.

    35. Flat Earth

      Space is fake thats why we are alone. Except for the evil demonic fallen angels of course.

    36. moobslikejagger

      Nope. The Earth, and the circumstances that have led to the proliferation of life being possible, are indeed super rare. But people who argue this aren't fully understanding how vast the universe (even just the bit that we know about) is.

    37. Alistair Aldridge

      Good stuff super interesting altho I suggest you 'can' the tunes they are a distraction to many people who like their facts sans the muzak. thanks.

    38. Essa Athar

      Why are we looking for alien life in planets which are Earth alike (or in the goldilocks zone)? Why are we looking for planets which can hold water on it's surface? What if alien life doesn't need the very specific elements to exist, like we do?

    39. Johnny Two Hands

      If there's really no other life out there in the universe then we are even more responsible to keep life going. It puts so much more pressure on us as a species to get things right as we advance and evolve. Because if humanity fails, that's the ball game. Life could be extinguished for billions of years to come, maybe forever (or as long as the universe has left to exist in the state its in now. Its a scary thought and one that leaves me kinda depressed to ponder. Finding out we are truly all alone in the universe could have drastic effects on our religion, art, culture, and society as a whole. If we do ever find out that is indeed the case I think the people that figure it out should maybe consider keeping it to themselves. IDK, maybe by then we'll be ready to hear it.

    40. The Seal in Black

      PBS just made me lose my cool...... they are completely wrong and fascist

      1. Element Zero

        *The Seal in Black* I’ll give you the wrong aspect on simply the moon speeding th he earths rotation up but Fascist?... Let me look that up.... okay I found this! Noun “an advocate or follower of the political philosophy or system of fascism”. Or “a person who is extremely right-wing or authoritarian” Or “a person who is very intolerant or domineering in a particular area”. So how and at what time stamp or stamps can you cite as them being “Fascist”? Or is this just hate bait?

    41. Omar Gonzalez

      And yet we have these billionare assholes trying to speed up the pipe dream space travel is instead of taming their fucking greed, and value what we have here on earth.

    42. SVM

      We haven't explored and understand our own planet yet, why waste time thinking about life outside of it!

    43. Nils Eik

      Love the videos, but i still think this new background music overlay takes away from the experience. Atleast lower it in volume. Hope you'll consider. Thanks

    44. codenameicarus

      I wrote this essay/review of Ad Astra for Jacobin magazine, which delves into the same themes, but from a perspective of the emotional consequences of realizing we might be alone in the universe: www.jacobinmag.com/2019/09/ad-astra-review-james-gray-arthur-c-clarke-space-intelligent-life

    45. Evan Eats

      Time and space only exist in our mind's they are not real, space has no properties Nikola Tesla the inventor of the modern world said this. Magnetism give's volume to the entire Universe. Mother Nature is more simple then 1+1=2. Centrifugal convergence and centripetal divergence, force & motion, inertia and acceleration. There was no big bang nor first cause. Nature and totality is more simple than you ever dreamed imaginable. But we human's have to quantify and make everything overtly complicated. Mother nature does not work how we like to think she work's. The simplicity of the Universe is more simple than 1+1=2, it's beautiful to understand this and see it in one's mind. Magnetism = Loss of inertia and the creation of space I.e. which gives volume to 100% of Nature. Di electricity or Electrostatic's Force and motion inertia and acceleration. The golden ratio from macro to micro everything is self seeking. A magnetic field is a torus and a hyperbaloid. Same shape's on the back of a pine cone, the spiral's of galaxies, flower's, facial symmetry everything in Nature follow this perfection of unity. Two most fundamental principle's of Totality Di- Electricity Magnetism force and motion inertia and acceleration, Centrifugal convergence and centripetal divergence. Mother nature is more simple than you've ever dreamed imaginable. But modern science make's it out to be something over complicated which is further from the truth. It's beautifully simple.

    46. Horny Toads

      The Peekaboo Analogy! Everytime i close my eyes & youtube / my browser you all cease to exist. My consciousness has created you all and you all serve a unique function ... you all truly exist only for my pleasure! I have giveth life and shall taketh away! But your existence is not weaved out of thin air. There is science behind it! Your existence is much like a covalent bond where I have given you all a life but it exists because I have given you a purpose! Truly, it can be summarized that In a way I am your master and ur all my slaves! so *KNEEL & BOW BEFORE ME YOU TURDS!* b4 i decide i should *Restart* my laptop!

      1. Horny Toads

        i think we all refer to the creator as Him for simplicity. And the term 'He' is NOT a male form & is neither a she! Frankly as humans we lack the capacity to really truly comprehend what God is.. for those who say there is no God, I feel like they are not looking at the evidence which is clearly all around them. While some debate the holy scriptures are all wrong and inconsistent; To them i say its a book of SIGNS not Science! Humans have made changes to the holy books, thats no secret.. however the essence of His message is well preserved; He has clearly instructed humans to continue to learn adapt and evolve! God didnt snap his fingers and the universe become.. No, he used science to make the cosmos! Now its up to us as humans to decode his secrets and follow his path where we become our better selves

      2. Ralph Goreham

        Interesting analogy. Actually the creator does have a people today who have "bowed before" Him. (The creator is neither male or female but for simplicity I referred to "him" as such).

    47. Sacred Oracle

      People who think they are the body have no idea about ETs. People who know the true layer of reality (Mind) are in a cosmos full of divine intelligences... Truthfully, a highly educated person is likely to be dumber than an ant when it comes to the nature of reality.

    48. Sacred Oracle

      Try meditation...

    49. john white

      I think the reason we have not seen anyone else, is that space is really, really big. All the math I have seen is that there should be at least 10 planets like Earth out there but again since space is really big and we have not been looking that long, we have not seen them.

    50. D B

      Earths are not rare, we had three in our solar system. The reason life reaches a bottleneck is diseases, no species has yet beaten the race it’s in against the microbes.

    51. xnonsuchx

      The jury is still out whether Earth has intelligent life.

    52. Jaren Williams

      the desire to find something else is what creates something else

    53. fredocorleone

      Interstellar travel is probably impossible anyways with all the various asteroids crossing between the stars...look at a star...it's blinking for a reason...stuff is passing in front of it throughout its great distance from you. So even if we do develop fast forms of travel, the potential vessel will probably smash into something. A piece of dust could destroy an entire vessel if it's traveling at a high speed.

      1. rent a shill

        Stars twinkle because of the atmosphere. The atmosphere acts as a lens, bending the path of light passing through it. At the same time, the atmosphere is moving - updrafts, downdrafts, and wind. The combination of the two means the atmosphere acts like a lens that is being constantly jiggled around at random. This makes the stars twinkle. Not "asteroids crossing between the stars" Outside the atmosphere, stars don’t twinkle

    54. Savage Coconut

      Wtf the moon 🌝? Helped regulate our planet, here I thought it to be eye 👁 watching us. Is it true we only see one side of the moon?

      1. Savage Coconut

        Wario Andretti I’ve heard that theory too.thanks

      2. Wario Andretti

        Yes and it's also 400 times smaller than the sun and 400 times closer which is why they appear the same size in the sky and it is also hollow and rings like a bell when struck. They say it shouldn't even exist

    55. Ginger Nut

      We are not intelligent. We are bacteria on a rock.

    56. Self Discipline

      I just cannot believe people are still atheists. The more science finds out, the more we look in awe at the 10/500 chance that we exist. With no answers, science just dances around a creator, and makes wild claims that make Noah's Flood, look like a gentle stream.


      why do you think that the environment needs to be suitable for life, why not the other way around?

      1. Sass Hole

        @Ethan Steel ha yeah, exactly

      2. Ethan Steel

        @Sass Hole Or the Vacuum of space. Or hell, even in the sun?

      3. Sass Hole

        If that is the case, why hasn't life evolved on the surface of Mercury?

    58. BigDaddyCool42

      We are made from the most abundant elements in the universe. Might not be rare. Universe is just so big

    59. Venom Supreme

      Actually there are 14 galaxies containing life bearing planets. This is very well documented.

      1. Ralph Goreham

        Sorry but nonsense. Reference please.

    60. Deep Ashtray

      We might just be alone in the universe because intelligence is an evolutionary dead end.