Are Axions Dark Matter?

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    What does the strong nuclear force, the fundamental symmetries of nature, and a laundry detergent have in common? They’re all important parts of the tale of the axion - a tale whose end may take us beyond the standard model and solve one of the most vexing mysteries in astrophysics.
    Hosted by Matt O'Dowd
    Written by Matt O'Dowd & Graeme Gossel
    Graphics by Leonardo Scholzer & Adriano Leal
    Post Production: Yago Ballarini, Max Willians, Pedro Osinski
    Directed by: Andrew Kornhaber
    Executive Producers: Eric Brown & Andrew Kornhaber
    The story of the axion is a classic physics tale: intrepid scientists delve deep into trackless mathematics in search of answers to a mystery. And there, against all expectations, they find the hint of a completely new and unexpected denizen of the natural world. In this case the mystery was a subtle inconsistency in the behavior of the fundamental forces. And the unexpected discovery? A brand new particle - the axion - which, while not proven to exist, may explain a much more famous conundrum. The axion may explain dark matter.
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    Published on 8 days ago


    1. Someone

      I think a better term for "symmetric" is.. Bipolar.

    2. Vini

      Background music sounds like Twin Peaks mystery song.

    3. Vini

      The standard model / QFT is slowly reaching its limit. Extrapolating from already existing equations will eventually just make you go in circles. You need some genuinely new ideas.

    4. King Ronin

      My question is why is a chiral neutron predicted to have an electrical charge? The positive version of an electron and a negative proton should mathematically produce a neutron of the chiral constituents but of similar basic properties?

    5. civota mu az

      Would watch this whole video but goddamn it feels like Billy Mitchel is waterboarding me

    6. Binyamin Tsadik

      Check out this paper: You are saying the same thing.

    7. Dr.V

      Wonderfully informative and fantastically interesting. Thank you kindly @PBS Space Time for making this.

    8. Make Racists Afraid Again

      Please don't say "visa" versa.

    9. Michael Sander

      To me, PBS Space Time is single best physics channel for folks who studied college-level physics, but didn't quite make it to (or through) physics grad school. Agree?

    10. Inspiración Original

      so... this means the Axiom could be used to support photon decay as an explication for dark matter?

    11. Badger

      I think axions and the theory itself could for the most part be replaced with formative causation as an account for dark matter/energy or other potential issues in our simulations.

    12. Charlie Meyer

      A proton-like composite particle made of Axioms could get a lot heavier! A "Protaxion" might even move sub light speed despite its superluminal parts.

    13. Kevin Reardon

      Dark matter only exists because we are memorized by the three body problem. The Moon and Earth are gravitationally locked, which is the same effect you see with the outer stars of a galaxy. There is no dark matter, there are gravitational rings on the outer reaches of a galaxy.

    14. Exoplanet Research

      There are galaxies with barely any dark matter. They should map the total magnet fields for the galaxies, then compare the dark matter content

    15. Clickmaster5k

      Calling us out. Geez

    16. Roman Buehler

      let me nerd away in my own world: that noise... what's that noise?!?!?! in ALL your videos, it's driving me insane and i have to focus hard on what you say... there's the music in the background, and there's you speaking, but there's also a noise, probably peaking around 600-800hz all over the videos... is that intentional by the editor to avoid hearing fatigue because of too clean sound? -> better way would be to use light audio compression on the voice track... is that because your recording environment is so noisy? -> with your budget you really should get better accoustic padding and isolation... is your editor hearing impaired and he never noticed? -> run some analysis on the sound output, find it and fix it, please!!!

      1. Roman Buehler

        it appears to be the mic input... FIX PLEASE!

    17. Net Tech

      Off topic, I know it is mathematically and physically possible to add positive mass to a point of spacetime but I'm curious if it is mathematically possible to add negative mass to a point of spacetime. A blackhole adds mass to a singular point by consuming mass increasing mass and gravity bending spacetime one way but is it mathematically possible to do the opposite creating negative mass effects to bend spacetime the inverse way?

    18. Audacious Scoundrel

      17 minutes of man talking to himself in the mirror.

    19. ChefHomesteadMaker

      That Thing That Newton Wrote, is it a must read?

    20. Marcin Zieminski

      There are 4 fundamental forces, and lots of different particles. How do scientist now which particle interacts with different forces? Ex.axions interact only with gravity and weak force, my question is why they interact only with those two forces, ? What is the mechanism behind it? Are there any laws which tell us that any given particle will interact with any given fundamental force?

    21. Chrizzie 78

      Does any of this matter?! Thank you, you've been a great audience.

    22. Brad Bradson

      Maybe there is no Dark Matter, maybe there is many Dark Matters

    23. Tirlon Burke

      You recently did a show on infinite universes and possibly the infinity of our universe. If either is the case, shouldn’t there be a wormhole we could traverse somewhere accessible on planet just waiting for someone enterprising to push a monkey through into a magnitar and one for us to travel somewhere slightly more pleasant?

    24. Imgay Asheck

      This channel still believed in inflation so I'm going to guess no

    25. Frank Jaeger

      I believe that in Latin the letter "c" is always pronounced as the letter "k". So the second way you pronounced it would be the most correct.

    26. Max Jones

      I love your content Cosmic Jesus.

    27. shipmaster3

      Do you think that there is some relationship between the photon energy and the strength of a magnetic field needed to convert it? or is it just a sufficiently strong magnetic field is needed to any photon into an axion regardless of energy ?

    28. Cierra Mist

      If the spin of a black hole can rip away its event horizon revealing a "naked singularity", would all the mass that's in the singularity come exploding out? Maybe the big bang was an event like this?

    29. Manus Artifex

      Anxious dark matter

    30. Sister of Gaia

      If you take the remove the first 5 00000 from the quantum vacuum number measurment of the Universe. It would explode 💥 and we would not be here 📌

    31. weylguy

      Wow - explaining an undetectable form of matter with another undetectable form of matter. Turtles all the way down? But I love this PBS program!

      1. Gareth Dean

        *Currently* undetectable. The hope being of course that we CAN detect it Nobody's sitting in bed going 'Boy, I hope we find nothing tomorrow!'

    32. mettaur01

      Is this where all the perverted Globe Earthers hang out?

    33. Scoring digits, son.

      Maj kohoni? Nahe!

    34. PouncingAnt

      Excellent. Sounds like Axions are an elegant solution to at least two big physics problems. Which leaves the question, Why might they not be? Is there anything besides the lack of experimental evidence to justify the title of the video being a question rather than a statement? (Of course, experimental evidence is a requirement of the scientific method, but.. you know how when they hype a particle, then you go and see the particle, and it's not as good as you were expecting...) P.S. A lot of people thought that about the Higgs.... But I thought it was a massive success. P.P.S. Sorry

    35. Amari Reyne

      "The universe may be truly spatially infinite" Even though I already had that idea in my head, hearing the words out loud from someone else really melted my mind. There's so many things we will never even begin to understand before the heat death of our own part of the whole universe. I mean, we used to think the milky way was the whole universe. And we were calling Andromeda an "island universe" What's to make anyone think the universe we observe isn't just one of... Billions? Trillions? Infinite? Universes. Guess we will never know 🤷‍♂️ I havent slept in 27 hours, go easy on me if you reply 😅

      1. Zenothys

        Amari Reyne You have a healthy skepticism and an inspiring curiosity. No reason to worry about responses imo! To give my two cents, space is only as large as needed to contain all possibilities (which I believe isn't infinite, but does inflate fast enough to redefine infinity to some larger number the instant the previous number is defined), and once you hit the "edge" of space, space becomes _time_ and more or less travels back to the Big Bang via the "beloved" Bogoliubov transformation.

    36. Cheasy

      a nerd channel and no 60 fps xD yr tittle has been revoked

    37. Mtf

      I used to watch these videos and then, frustrated for not being able to understand, go to the pub . Now I 've thought better and I go to the pub BEFORE watching the videos and suddenly they are crystal clear .

    38. Doldol D

      Really interesting episode

    39. frysebox1

      Me: Officer, why am I being detained? Officer: 2:18

    40. Lance Tschirhart

      Great apes _are_ monkeys. Jesus Christ, these cosmologists..

    41. Manu V

      Do I come here just to feel dumb!?

    42. Art

      Had to downvote after the first two seconds :(

    43. Bill McDonough

      Matt, just to 'nerd all the way': the great apes (or Hominidae) are a Family within the infraorder Simiiformes... the monkeys. So strictly, all apes *are* monkeys. Catarrhini 'Old World' monkeys, in fact.

    44. Gabriel Desmarais

      I guess it is official, we can't out-nerd Matt.

    45. Kez

      Can you be straight and wear a pink shirt into a gay bar?

    46. Jason Williams

      How can observable time not affect observable mass

    47. Nicolás Celedón

      Did anyone read axioms and thought 'those damn matematicians'

    48. gusthebroken2

      Jargon that no one understands .


      So I have a question... Do black holes change the topology of the fabric of space-time?

    50. Toni Kotinurmi

      Doing physics in univ, for example speed of light (yeah, 30 years ago...) tests with rather strong lasers etc it was OK if we hit within 1e10..15 - just as long as we explained where error marginals came from. That latter part is more important than hitting target. So come on... If you measure something, do it again and again in different ways until you say it's inaccurate.

    51. Sammy Smith

      You and the guy from Ancient Aliens are my heroes, so good information.

    52. Vistico93

      An infinite universe means I would have an infinite number of tries to get my life right though only in an infinite number of them will I start off with memories of my previous attempts to do so...

    53. Nick Moraitis

      We can only need out to the fullest extent of our own universe.

    54. Mich ael

      Next video: Are VPN services dark matter?

    55. C Apt

      Answer below: How many seconds before you are lost on this video?

    56. Ri4s co

      What if dark matter is just an effect of dark energy pushing on gravity

    57. TheExpatpom

      If axions, assuming they exist and are the dark matter physicists have been looking for, are produced in the core of fairly unremarkable star like our sun, is the next question why the stars in those dark matter free galaxies that have been discovered haven’t been producing axions? For that matter if loads of axions were produced during the Big Bang wouldn’t we expect them to end up in the same regions and structures as ordinary matter, and for there to be no galaxies without them? Or is there a possible answer that’s the subject of a future video?

    58. Mainland Empire Records

      AHHAHA nerd all the way. Cone'd a phrase.

    59. Fundemort Grey Prime Defender of Truth and Justice

      But Sheldon got his Nobel from Super-Asymmetry theory. (this is obv just a joke).

    60. Mainland Empire Records

      I love this show. I started watching in 2018, and I haven't stopped since. Thank for you incredibly high value content.