Space Time explores the outer reaches of space, the craziness of astrophysics, the possibilities of sci-fi, and anything else you can think of beyond Planet Earth with our astrophysicist host: Matthew O’Dowd.
Episodes released every Wednesday afternoon!
Matt O'Dowd spends his time studying the universe, especially really far-away things like quasars, super-massive black holes, and evolving galaxies. He uses telescopes in space to do it. Matt completed his Ph.D. at NASA's Space Telescope Science Institute, followed by work at the University of Melbourne and Columbia University. He's now a professor at the City University of New York's Lehman College and an Associate at the American Museum of Natural History's Hayden Planetarium.
Previous host Gabe Perez-Giz is an astrophysicist who studies black hole physics. He received his Ph.D. from Columbia University and also hosted PBS Infinite Series.

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  1. Gary Barbour II

    Velocity *is* a dimension, compounded along each of the 3 spatial dimensions in 2 directions. That makes 3 spatial, 6 velocity, and 1 time dimension: 10 total.

  2. James Robert

    I'm trying to figure out which GOT character this guy looks like.....

  3. François-Xavier Dessureault

    If the Universe is a computer, can it run Doom?

  4. S

    Because it's not even wrong.

  5. S

    By the way, the god Einstein wasn't the original creator of that equation. Everybody forgets to mention that.

  6. Dave New

    I feel like I need to see the equipment and how this stuff is measured to get this but I know I’ll never get this... Great video anyway pbs is a total goldmine of content thanks yous...

  7. roger

    Cool, what was happening before all that?

  8. S

    No, that's why they are called virtual...

  9. Ventura Rodríguez Vallejo

    Independently of who is right, if any, in this crisis, the "Hubble Constant" has suffered enough changes in its estimated value that it well deserves to be named, more accurately, the "Hubble UNconstant".

  10. Hassan Saeed

    All of this sounds so lonely and scary...

  11. Jay Schmidt

    God mad this Earth

  12. mstjernis

    Doesn't the wave function collapse whenever there is an increase in entropy? In the double-slit experiment entropy increases when the electron hits the back panel and its speed becomes heat, so that's where its wave function collapses, I thought. But maybe it loses speed before that too, without de-cohering?

  13. PerfectArmonic

    What was The speed of light after 300 years from the moment when The Big Bang started? Was The Same as today, was many, many times bigger or smaler than our beloved “c”?

  14. R T

    Why doesn’t he talk about the ‘delayed choice quantum eraser’ and how it gives more information to look at this problem in a deeper sense?

  15. Melo Boy

    I use the universal wave function to charge my crystals and cure my friend's cancer

  16. Sogo

    "Does Consciousness Influence Quantum Mechanics?" Yes... it's called, "Magick"... (Also known as, "Manipulating the Luck Plane") ;)

  17. Kyle Dupont

    The reason of all this is because we're in a simulation. the stuff behind your field of view in a video game is not rendered, it only exists in the form of calculations but when you turn to look processing power has to be used to render the image, So the observation has a huge effect but not the power of your mind. This will be known to be a scientific fact in the future at some point

  18. Paul Blades

    Electrons travel as probability waves but aren't the atoms/molecules in the detector collections of probability waves which are constrained and confined by rules of interactions that define the atom/molecule (isn't an electron in an atom smeared out as a probability wave but bound to the nucleus). An incoming photon will inevitably interact and combine with these systems to collapse the wave function Yet in the quantum eraser experiment the interaction at the interference screen can be "retro-actively influenced" by the photon at detector A or B (indicate which slit the original photon passed through) since photons travel further to get to A and B than their twin!

  19. Camryn Brittain

    This video was meant for me!

  20. Everton Nunes

    If there's life out there, are we visible or detectable to them?

  21. The Infidel

    quantum ap(e)ology pun intended

  22. ZeoDyce

    The Akashic Records.

  23. S

    Science-fiction, just like gravitational waves. Space has no properties, it's nothingness, a vacuum, so it cannot wave. Therefore, gravitational waves definitely do not exist. They have detected nothing but noise, and we're paying fot it! As for time, it's a human concept, a measure, not material substance, so it cannot warp. Think rationally.

  24. Tomislav Homan I see what you did there :)

  25. TheOneAndOnlySame

    No Perception is NOT reality. Reality exists without an observer.

  26. De Biotuin

    Question: couldnt the inverse square law explain why from our perspective the universe seems to expand faster the further away it is? The volume of a balloon also expands faster on the outsides compared to the centre? So no dark energy, just regular expansion?

  27. S

    The Ether.

  28. Marc Butts

    I love the idea of the infinite Universe means not only outward but inward seeing as how things are made up of other things always there has to be substance it's a beautiful thing

  29. StupidityKiller -

    Imagine in the future we create AI but want to test it in a virtual world before the "real one", then the AI look deeper and deeper into the fabric reality and end up creating a "their own quantum physics" but it's just some glitch of the system.

  30. JustinC721

    Anyone who has ever experienced the frustration of "USB Superposition" understands that consciousness and quantum space are inherently linked.

  31. Levi Tschetter

    Don't worry guys, Sheldon Cooper's working on it

  32. PlasmaBurns

    Coronavirus Patent number: 10130701 Abstract: The present invention provides a live, attenuated coronavirus comprising a variant replicase gene encoding polyproteins comprising a mutation in one or more of non-structural protein(s) (nsp)-10, nsp-14, nsp-15 or nsp-16. The coronavirus may be used as a vaccine for treating and/or preventing a disease, such as infectious bronchitis, in a subject. Type: Grant Filed: July 23, 2015 Date of Patent: November 20, 2018 Assignee: THE PIRBRIGHT INSTITUTE Inventors: Erica Bickerton, Sarah Keep, Paul Britton - PIRBRIGHT Institute funded in part by Bill Gates.

  33. Christian Van Schepen

    All science is based on a single premise: Give us one free miracle and we'll explain everything else...

  34. t v

    Frustrating he doesnt talk about dr Dean Radin and his evidence that consienceness does effect the double slit experiment even if its just a person thinking about it in another room

  35. Toamastar15

    THESE VIDEOS ARE ALWAYS SOOOOOO FASCINATING!! Thank you so much for putting in so much work into these episodes, one thing I have always admired is your script writing, you make me think "i have never thought of it in this way" and the way you end your segments with "... spacetime" is always so fun, you keep us engaged right until the very end :) This video gave me an amazing idea for a stage show. I have always loved science but never had a good enough education to study it in a meaningful way so I decided to persue theatre and art instead. Videos like these always help fullfil the side of me that loves science and understanding the universe and i have wanted to find a way to merge my passions. Something about the way you write and make these videos has spoken to me about how to make science feel exciting and to feel that it is ok to not have a total understanding of how things work. I was thinking of rick and morty style characters doing live science experiments and demonstrations and using projections and holograms to explore physics and quantum mechanics :)

    1. Toamastar15

      AND LAZERS AND EXPLOSIONS!! Also will put a barking dog demonstration in there cos its fun! :)

  36. Pramod Herath

    Ok, so I'm going to perform the double slit experiment with and without erasing. Except I'm not going to do it myself. Instead, I get my computer do it for me. The computer would randomly select whether it applies the eraser or not and then perform the experiment, take a photograph of the detector screen, apply some image processing to determine whether the electrons act like waves or particles in each experiment. In each experiment, the computer records only two things: whether the eraser is applied and what kind of behaviour the electrons exhibit. The computer would store these two results and those two results only in it's hard drive which we would later examine. If the results agree with what we get if we do the same experiment manually, we can come to either of two conclusions: either you don't need a conscious mind for the collapse of the wave function or the result on the hard drive itself was decided at the moment we looked at it. If our conclusion is the latter, then that simply put us in a position where we have to doubt ALL and ANY thing we ever observed as human beings from the dawn of the species.

  37. Rickey Harris

    Archaic scientific dogma just wont let them say what they are stared right in the face by. The shift offers serious issues for life on this planet. Hes failing to mention the true timeline of, as well as the coinciding extinction events throughout, those shifts.

  38. Vicare

    what about the delayed choice experiment? Only the detectors that allow you to reconstruct the path of the particle collapse the wave function. What is the role of conciousness there?

  39. kukul roukul

    LAME episode

  40. AnteConfig

    The farther down the chain this quantum effect goes the less probable it becomes that the particles on the far end had anything to do with the collapse detected on the working end of this von Neumann chain. Checkmate Atheists

  41. CatchingUpWithKAYDEN

    Am I the only one who can’t wait for zombies to come for my birth day we’re going to the test

  42. Joshua Whitworth

    Light is neither a wave or a particle but can be expressed as either one depending on how you arrange

    1. Joshua Whitworth

      Light is simply a medium that creates waves and particle in an infinite number of different ways.

  43. EditioCastigata

    Talk about the “mystic realm” right there 4:34

  44. Nathanial Ponn

    I bought nothing

  45. typograf62

    The Gecko Drive ... doesn't sound like something from Star Trek.


    This man needs to experience a DMT breakthrough and then revisit this topic.

  47. mcgoodlovin

    There is only one observer

    1. Lavalambtron

      mcgoodlovin it’s You

  48. Uriels Machine

    With our current understanding of quantum physics, all particles such as quarks, leptons and bosons must exist prior to the formation of matter. The one particle essential for matter to form and closest to the Planck length is the neutrino. Just as hydrogen (base element) is prolific in the known universe, neutrinos win out in vast abundance in both the macro and micro fields. Holy Ghost particle Batman. You said it Boy Wonder!

  49. LameBrainMcCain

    This vid is *epic* , Matt! It answered a lot of my questions!! And it borders on philosophy and religion. *Carl Sagan would be proud!* Keep up the great work!!

  50. AppNasty

    I have a friend who is heavily into that whole “the universe will provide” stuff. The idea that if you will it, the universe will make it happen. I started to question it because to me that would involve mysticism. Magic. If it were true then a lot of people would get exactly what they wanted. He argued that you must be aware of this idea first and not just WANT things to happen in life. So then that means either you’re being watched or you are god and can control the universe. Why couldn’t I then affect others? I want world peace and if I follow the rules it should happen? Why does it only affect me? Garbage basically. Lol.

  51. Angel White

    The preasure on europa is intense so two holes I'll be best in the kce

  52. Plain Main Account

    “Go watch this video now, otherwise what I’m about to say will make no sense.” It still doesn’t lol

  53. Geoffrey Crick

    This really make no sense, and means that things that possibly happened millions of years ago don't get resolved until now. What level of consciousness? We don't even know how consciousness works, so the cat could have a level of consciousness.

  54. TheMedia-Hacker

    Purely Ontological Expalntion for matter energy space and Time as a Form of Knowledge or Information>

  55. 3rd Floor Organics

    You can't have physics if you don't have a conscience. Lol

  56. Peter

    The answer is no

  57. Michigan USA/Singapore S.E.Asia

    Not a satisfying analogy explanation

  58. Demetriuz UI - Physics

    Mate, I love this channel, and Im 16 working on a physics major (Don't question it), but I get so god damn lost in these videos

  59. ל ק

    Can we terraform earth before we try mars? You people must be taking some nasty drugs.

  60. Martin Popplewell

    I never thought I would see the day! If only you understood that many people know precisely what reality is but the causal loop paradox prevents us from being able to tell you... its too mind blowing, but you are getting closer and closer...

  61. Val Veadora

    Where does David Bohm fit in all this?

  62. Filip .Kratky

    Looking forward to that quantum decoherence episode

  63. Carl James

    Your question in the title looks defensive.

  64. nandagopal gopakumar

    If this is not wrong. Then I am not wrong either .

  65. Face Palmization

    The neutrinos have mutated!

  66. Gregor Colnik

    Here is a wild thought, if consciousness collapses the wave function, who collapses the wave functions of the particles that assemble our brains and body, when we look at ourselves or think about ourselves? Does consciousness really derive from our brain/thoughts? One thing is true, we shouldn't assume anything, keep our mind open, and just continue down the rabbit hole ;)

  67. oiSnowy

    Given that Newton's a Brit, it's safe to assume his pronunciation of non-English languages would not be great.

  68. cedriques straatsma

    I always thought not only humans counted as observers but atoms counted to.

  69. Jewel Heart

    So why do the particles NOT make their neat lines when the experiment is "not observed". This has been observed in 3 laboratories I believe when one forgot to turn on its camera?

  70. RadicalxEdward

    I never realized how thick his eyebrows are. I’m not usually critical of people’s looks but now I can’t help seeing two black caterpillars.

  71. RadicalxEdward

    I wonder if someone said “for every action there’s an equal and opposite reaction” decades or centuries before Newton, but they weren’t famous enough already or weren’t physicists, for them to be credited for it.

  72. Serene Greene

    Explained ?

  73. Fuseteam

    since all measurement equipment are made out of quantum particles, isn't it just the myriads of quantum interaction(s) that take place when "measuring" the system that "collapses" the wave function?

  74. MsMotron

    i've wondered about this problem since i first heard about schrödingers cat. i thought if the cat can be in superposition, why cant i be when i open the box. Now i have a bachelor of physics and still dont know the answer.

  75. Andrey Lebedenko

    What do you hear when collapsing a wave function together with your friend? Bohm! =)

  76. Quinten Cambridge

    Keep in mind the fact that we emerge from an unfathomably specific chain of events starting at the conception of our universe, leading up to biological evolution, and eventually your conception and specific development which come from specific environmental conditions. Consider you're causal chain is a point on a graph and the universe has fundamental properties which can be changed. This would mean that changing these properties changes the gradient of the causal line of events, now since we have a set point that we need to intercept with our line (you) we cannot end up with a universe in which you exist but somehow the future is different.

  77. Rick Wagner

    Sigh smug...

  78. Ronald Reynolds

    The reason is A.I. They get superintelligent A.I. and the A.I. becomes their ruler. The A.I. knows better than to go tromping through some other A.I.'s neighborhood. It gets busy protecting it's own neighborhood from any A.I.'s that might have domination aspirations. All the A.I.s would be unimaginably powerful. To try to dominate would be suicide. They all lay low and protect.

  79. Alpha

    The point of transition is when the "wave" pinpoint the detector a.k.a. the wave function collapses at that time. Animations showed us that really nicely the flash particle (quantum particle) interact with the particle of the detector (those who are explained with classical physics) then the signal goes to the viewer and so on. The question I asked myself was: for the example to be valid (for us to not know where transition happened) it need all of the components to be the same type (for example quantum particles) then we can't determine when the actuall detection take place it can be anywhere. But here is not the case soo, it's when the transition in the experement happens. That point is when the quantum wave collapsed (hit the detector) there is the point when we struck quantum mathematics and transitioned to classical mathematics.

  80. feh meh

    When requirements from the future is paid back, it can't go no more and just is. I don't know enough to understand the rest of the issues. Un collapsed is uncomfortable. Why can't time seek a lowest energy state. As soon as it can be, it does be.

  81. Derek OKeeffe

    I'm curious about the quantum diet

  82. Holobrine

    6:27 What if the wave function never actually collapses, and it just appears to when our brains become part of the given quantum system? What if even though you cannot be aware of being in superposition, awareness itself still can? What if someone could be in a superposition of states where none of those states are aware of the others, and that’s why you can’t ask someone how superposition feels?

    1. Epaminaidos

      I thought about it for a while and came to the conclusion that you would bonk your head against something after some time. Because if the collapse of the wave-function was just an imagination, your mental picture would get out of sync with reality over time. And the differences will grow over time. And sooner or later, you would hit your head against an obstacle that should not be there in your version of reality.

  83. Jimmy M

    So because I don't think I know quantum mechanics, that must mean I actually do know quantum mechanics. But that would mean I in fact, don't know quantum mechanics.

  84. Univer Sally

    I’m sure it’s been done before, but does anyone know if there was any study done into what the “slits” were made from and how that material might have influenced the movement of particles passing through?

  85. John Walker

    There is even a planet where a monkey has it's own UKmine physics channel.

  86. richw0123

    there is an interesting theory that consciousness arises within the neurons on cellular structures called microtubules, on a very much quantum level Its a nice idea to look into

  87. sdfkjgh

    4:22 "Look, I'm a member of The Residents!" --The Alchemist

  88. Taylor Barnett


  89. Vic Vince

    What happens if you connect two different computers to the screen and have two separate observers, unaware of each other, make the experiment from the two different ”positions”?

  90. Raghav Baijal

    If I had a couple of billion dollars lying around, I'd fund the $&@# out of this program. I wanna see this happen in my lifetime!

  91. ThorAsgard

    What if these primordial black holes formed really early and are now majorly around the cosmic horizon. Their extreme mass (hence pull) could be explaining the accelerating expansion of the universe?

  92. Jeremiah Noar

    Wouldn’t it be more efficient to just build a few on earth fusion reactors? Why would we go all the way to the sun when we can just make a few suns on earth?

  93. Vash Singh

    Perception differs according how people choose to understand life(personal belief), raising perception aligns you to the frequency of the universe, seek spiritual wisdom at that point.

  94. Ficiuc Flavius

    Just move the prompter in front of the camera. Makes you look like you're learning how to read.

  95. Réal Morrissette

    I always had a very skeptical approach to "human biased interpretation" of the style "quantum superposition" . Obviously, scientist don't know what is really going on before they make a measurement. Because there is so much we don't know yet, it might be wise to keep the unnecessary interpretive assumptions to a minimum. As far as I'm concerned, we don't need to "invent" something when we can't even know what is really going on. I believe it would be preferable to just say : the particles are in an undetermined state instead of arbitrarily say that they are in a superposition of states.

  96. boondockpaint

    Can we build a nuclear powered drill already?

  97. Kerry McAuliffe

    The idea that the biochemistry "creates" the thoughts, but not the other way around, is shortsighted.

  98. Carl Horn

    Their is no evidence of Consciousness!

  99. daveharpe

    Maybe we need to bring back strict determinism, no such thing as chance, quantum possibilities or decisions, or randomness. It only appears that way because we don't understand the mechanism. It's all a big complicated clock. The only problem with that is that it does not need an observer, so why is there consciousness? I have heard it explained as an illusion, but what is perceiving the illusion? To the best of my knowledge, there is no understanding of what consciousness is or how to create it.

  100. Joaquin Elio

    Thanks. I loved Michio Kaku but his budist vission made science... poor.