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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Үзсэн тоо


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

    SomeoneSomeone8 цагийн өмнө
  • Background music sounds like Twin Peaks mystery song.

    ViniVini11 цагийн өмнө
  • 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.

    ViniVini11 цагийн өмнө
  • 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?

    King RoninKing Ronin12 цагийн өмнө
  • Would watch this whole video but goddamn it feels like Billy Mitchel is waterboarding me

    civota mu azcivota mu az13 цагийн өмнө
  • Check out this paper: You are saying the same thing.

    Binyamin TsadikBinyamin Tsadik16 цагийн өмнө
  • Wonderfully informative and fantastically interesting. Thank you kindly @PBS Space Time for making this.

    Dr.VDr.V16 цагийн өмнө
  • Please don't say "visa" versa.

    Make Racists Afraid AgainMake Racists Afraid Again17 цагийн өмнө
  • 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?

    Michael SanderMichael Sander17 цагийн өмнө
  • so... this means the Axiom could be used to support photon decay as an explication for dark matter?

    Inspiración OriginalInspiración Original19 цагийн өмнө
  • 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.

    BadgerBadger20 цагийн өмнө
  • 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.

    Charlie MeyerCharlie Meyer20 цагийн өмнө
  • 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.

    Kevin ReardonKevin Reardon20 цагийн өмнө
  • There are galaxies with barely any dark matter. They should map the total magnet fields for the galaxies, then compare the dark matter content

    Exoplanet ResearchExoplanet Research22 цагийн өмнө
  • Calling us out. Geez

    Clickmaster5kClickmaster5kӨдрийн өмнө
  • 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!!!

    Roman BuehlerRoman BuehlerӨдрийн өмнө
    • it appears to be the mic input... FIX PLEASE!

      Roman BuehlerRoman BuehlerӨдрийн өмнө
  • 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?

    Net TechNet TechӨдрийн өмнө
  • 17 minutes of man talking to himself in the mirror.

    Audacious ScoundrelAudacious ScoundrelӨдрийн өмнө
  • That Thing That Newton Wrote, is it a must read?

    ChefHomesteadMakerChefHomesteadMakerӨдрийн өмнө
  • 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?

    Marcin ZieminskiMarcin ZieminskiӨдрийн өмнө
  • Does any of this matter?! Thank you, you've been a great audience.

    Chrizzie 78Chrizzie 78Өдрийн өмнө
  • Maybe there is no Dark Matter, maybe there is many Dark Matters

    Brad BradsonBrad BradsonӨдрийн өмнө
  • 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?

    Tirlon BurkeTirlon BurkeӨдрийн өмнө
  • This channel still believed in inflation so I'm going to guess no

    Imgay AsheckImgay AsheckӨдрийн өмнө
  • 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.

    Frank JaegerFrank JaegerӨдрийн өмнө
  • I love your content Cosmic Jesus.

    Max JonesMax Jones2 өдрийн өмнө
  • 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 ?

    shipmaster3shipmaster32 өдрийн өмнө
  • 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?

    Cierra MistCierra Mist2 өдрийн өмнө
  • Anxious dark matter

    Manus ArtifexManus Artifex2 өдрийн өмнө
  • 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 📌

    Sister of GaiaSister of Gaia2 өдрийн өмнө
  • Wow - explaining an undetectable form of matter with another undetectable form of matter. Turtles all the way down? But I love this PBS program!

    weylguyweylguy2 өдрийн өмнө
    • *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!'

      Gareth DeanGareth Dean21 цагийн өмнө
  • Is this where all the perverted Globe Earthers hang out?

    mettaur01mettaur012 өдрийн өмнө
  • Maj kohoni? Nahe!

    Scoring digits, son.Scoring digits, son.2 өдрийн өмнө
  • 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

    PouncingAntPouncingAnt2 өдрийн өмнө
  • "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 😅

    Amari ReyneAmari Reyne2 өдрийн өмнө
    • 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.

      ZenothysZenothys2 өдрийн өмнө
  • a nerd channel and no 60 fps xD yr tittle has been revoked

    CheasyCheasy2 өдрийн өмнө
  • 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 .

    MtfMtf2 өдрийн өмнө
  • Really interesting episode

    Doldol DDoldol D2 өдрийн өмнө
  • Me: Officer, why am I being detained? Officer: 2:18

    frysebox1frysebox12 өдрийн өмнө
  • Great apes _are_ monkeys. Jesus Christ, these cosmologists..

    Lance TschirhartLance Tschirhart2 өдрийн өмнө
  • Do I come here just to feel dumb!?

    Manu VManu V2 өдрийн өмнө
  • Had to downvote after the first two seconds :(

    ArtArt2 өдрийн өмнө
  • 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.

    Bill McDonoughBill McDonough3 өдрийн өмнө
  • I guess it is official, we can't out-nerd Matt.

    Gabriel DesmaraisGabriel Desmarais3 өдрийн өмнө
  • Can you be straight and wear a pink shirt into a gay bar?

    KezKez3 өдрийн өмнө
  • How can observable time not affect observable mass

    Jason WilliamsJason Williams3 өдрийн өмнө
  • Did anyone read axioms and thought 'those damn matematicians'

    Nicolás CeledónNicolás Celedón3 өдрийн өмнө
  • Jargon that no one understands .

    gusthebroken2gusthebroken23 өдрийн өмнө
  • So I have a question... Do black holes change the topology of the fabric of space-time?

  • 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.

    Toni KotinurmiToni Kotinurmi3 өдрийн өмнө
  • You and the guy from Ancient Aliens are my heroes, so good information.

    Sammy SmithSammy Smith3 өдрийн өмнө
  • 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...

    Vistico93Vistico933 өдрийн өмнө
  • We can only need out to the fullest extent of our own universe.

    Nick MoraitisNick Moraitis3 өдрийн өмнө
  • Next video: Are VPN services dark matter?

    Mich aelMich ael3 өдрийн өмнө
  • Answer below: How many seconds before you are lost on this video?

    C AptC Apt3 өдрийн өмнө
  • What if dark matter is just an effect of dark energy pushing on gravity

    Ri4s coRi4s co3 өдрийн өмнө
  • 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?

    TheExpatpomTheExpatpom3 өдрийн өмнө
  • AHHAHA nerd all the way. Cone'd a phrase.

    Mainland Empire RecordsMainland Empire Records3 өдрийн өмнө
  • But Sheldon got his Nobel from Super-Asymmetry theory. (this is obv just a joke).

    Fundemort Grey Prime Defender of Truth and JusticeFundemort Grey Prime Defender of Truth and Justice3 өдрийн өмнө
  • I love this show. I started watching in 2018, and I haven't stopped since. Thank for you incredibly high value content.

    Mainland Empire RecordsMainland Empire Records3 өдрийн өмнө