Are Axions Dark Matter?

[@betacenturion237]

Hello PBS Space Time. I'm finishing up my REU with the Axion Dark Matter eXperiment (ADMX) with the University of Washington, and I just wanted to thank you for presenting axion physics in such a clear way. I was aware of the strong CP problem during the whole internship, but since I was focused on studying microwave cavities I never got the chance to learn more about it. This video helped me sound like a boss at the end of my presentation, and of course, the video was awesome regardless of the context it has to me. Just wanted to say thanks for helping me out.

[@cgraghuyt2085]

❤

[@Swagjay369]

Results?

[@InsertHandleHere968]

Sounds like this is an exciting time to be studying axions right now! Some really interesting stuff coming

[@lukesyrios]

I remember always thinking the Axion was one of the cooler names of all the theoretical particles. Kind of a let down that its named after detergent. Maybe we can get a Tide Pod particle next

[@ryanthurman92]

We’d have to find a way to convince children it wasn’t food

[@AntofFlame1113]

I was thinking the same thing Luke

[@Evan.the.Butler]

Tide Podticle

[@joshyoung1440]

God damn it, I need to stop coming to the comment section before finishing the video. I keep getting spoilers lmfao

[@joshyoung1440]

Anyways, I don't think we'll get a Tide Pod particle, but I do see a chance in someone naming a laundry product Quantum Pods or some such

[@keithkeller4546]

"If you're gonna nerd, why not nerd all the way?" Love it.

[@UltraBadass]

I have the feeling he wanted revenge for.. Something

[@FLScrabbler]

Verbing weirds language...

[@azurlake]

Omg... this is just feeding the troll! what have you done!!?

[@vealck]

Well, distinction between apes and monkeys is not present in every language. In polish they both can be called monkey. When talking more precisely, we say something that would translate roughly as 'chief monkey' to denote apes in particular.

[@djmcbratney]

@@vealck Yup. And phylogentically, apes are descendents of monkeys, so there's no way out on that front, either. In fact, some very dedicated traditionalists have occasionally tried to redefine either Old World or New World monkeys as not-monkeys to escape. The idea that we apes are not monkeys is a traditional hypercorrection even in English and based on the whims of nineteenth-century English schoolteachers.

[@FullModernAlchemist]

Matt. You are to physics what Bob Ross is to painting. You make me amazed and profoundly calm at the same time.

[@elicallaway342]

Wasn't Bob a mediocre painter at best, who only had a painting career because of public funding? Oh I do see the correlations to this show.

[@Ru-mk8lp]

@@elicallaway342 why so vicious?

[@elicallaway342]

@@Ru-mk8lp hardly vicious. Learned to paint watching Ross, when I was 8. Dumbed down science is why America is losing the science race. For instance Elon Musk making NASA look moronic. NASA is ripping off the taxpayers when some dork programmer could do it better

[@Shadow-In-The-East]

@@elicallaway342 I give you 3/10 trolling, please try harder next time.

[@mastershooter64]

@@elicallaway342 2/10 for trolling, you're not a good troll mate

[@Blubb5000]

I’ve heard some of the words he said before.

[@philipmumford7871]

I'm with you there. I know it's English but not sure I understood very much of what he was saying!!! Brain feeling a bit small today 🤪

[@Reignor99]

It helps to pretend that he's a friend speaking directly to you. I pretend that I'm the ruler of earth and he's one of my scientific advisers. Once I believe that his words are intended for *me alone,* my brain is tricked into paying more attention/grasping more, as if I were listening to a friend make a high rant. I find myself nodding and understanding more when I pretend this.

[@keeleehudson]

@@Reignor99 That's genius.

[@TheGauges420]

@@Reignor99 16:41 is for you. If you're going to nerd, why not nerd all the way?!

[@heyquantboy]

I hear the words, but when they're strung together- makes no sense.

[@LukeDupin]

It's refreshing to find a channel that's willing to talk about complex subjects without "pulling any punches". No simplified metaphors.

[@RiverGriffith2016]

I read the title of this at first as "Is Dark Matter Anxious?" and I'm not sure what to do with that question

[@matthewcaylor342]

Two questions, what does darkmatter have to be anxious about and is darkmatter sentient?

[@amafuji]

I would be anxious too if I was hiding and everyone was trying to find me

[@garanceadrosehn9691]

I first thought the title was "Are Axioms dark matter?", and wondered what that would mean to all of mathematics.

[@hope_youhaveagoodday]

Exurb1a will answer the question!

[@projectmanagement2356]

Did they prevent you from streaming nailed it in 4k?

[@sebastianelytron8450]

Read the title as "Are Axioms Dark Matter?" Based on how much I understood about them in advanced calculus, they might as well be.

[@yyeeeyyyey8802]

@@littlecousin5630 Perharps he's refering to the axioms that build the real numbers? The real numbers can either be built from rational numbers (thus being indirectly built from natural numbers) or they can also be defined by axioms themselves.

[@lonestarr1490]

@@yyeeeyyyey8802 Even if you derive the reals from the rationals, you need the cutting axiom of Dedekind to assure completeness of order.

[@yyeeeyyyey8802]

@@lonestarr1490 Dedekind cuts are a definition, not an axiom. When you build the real numbers with them you define what is a cut, define the real numbers as the set of all those cuts, and then show that such definition has all the properties of the real numbers. So no axioms are used, since all properties can be proven from the definition.

[@arislanbekkosnazarov9644]

Man, I was stomped at first. I thought to myself "Do they study theoretical particle that goes by the name Axion in just advanced calculus?". Then I read again, and yep, he was talking about Axioms, not Axions.

[@nathanlevesque7812]

I feel like the comment went over the heads of anyone familiar with advanced calculus.

[@T33K3SS3LCH3N]

> "What do you do professionally?" "I study laundry detergent." > "So you work for a soap company or?..." "I'm astrophysicist."

[@themoribundapathetic4530]

i w o u ld l o v e t o b e a n a s t r o p h y s i c i s t

[@billymonday8388]

cringe

[@nrv8013]

Wilczek is not the best expressing his ideas in words - but his jokes and sense of humor are fenomenal

[@themoribundapathetic4530]

@@nrv8013 phenomenal like pherones

[@nrv8013]

@@themoribundapathetic4530 that needs a Gerard 't Hooft fifth dimension

[@Rasecz]

I love episodes that explain how modern experiments are pushing the limits of the standard model

[@gamerkaue88]

"This particle can explain dark matter" Yeah, I've heard this enough times to know where this is going...

[@schokoladenjunge1]

Truly an issue. Dark matter candidates from modifications of theories are a dime a dozen, and same goes for new particles...

[@schokoladenjunge1]

Truly an issue. Dark matter candidates from modifications of theories are a dime a dozen, and same goes for new particles...

[@niqhtt]

Eventually it's going to be correct

[@scipioafricanus2071]

Yeah there are too many ifs in this axiom hypothesis. Seems more like researchers are grasping for straws.

[@Pauly421]

So true lol. So many clickbait articles too...

[@qwerty_and_azerty]

“If you’re gonna nerd, why not nerd all the way?” This is the deepest insight any of the infinite version of me have ever gotten from PBS Spacetime video. Nicely done!

[@TomTom-rh5gk]

It is a dumb idea. Nerds are people not machines and people will fool you when you lest expect it.

[@ThePunkPatriot]

This video, my level of understanding kept oscillating between feeling like I am starting to get it, to feeling like you are speaking Klingon.

[@Southpaw17]

"If you're gonna nerd, why not nerd all the way?" is a challenge that I'm sure will never be regretted.

[@lereff1382]

I get the feeling the editor messed up the framerate of the recordings for this episode...

[@luwn00bz]

Yes, very triggering. You can check "stats for nerds" from the video and see "dropped frames". Which is 0. Which means its not my end :D

[@koenvandamme6901]

Axions did it.

[@yootoob6003]

It's a PowerPoint slide

[@iainballas]

Oh good, not just me.

[@Ganerrr]

came here to look for this

[@mainlandempirerecords8724]

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

[@Gengsta88]

can we somehow give this man an oscar or an grammy or an nobel prize or anything like that becouse he clearly deserves it

[@js27-a5t]

Yeah, what's the physics of getting an Emmy, Grammy, Oscar, and Tony.... Is that a kind of entanglement?

[@ZeroOskul]

Wow! Big difference. You got a fiction editor to revise the flow of this episode! You opened in a way that set up the story arc that MUST end with "SpaceTime", and just as I realized that you began a narrative tale. Great presentation! I am 32 seconds in.

[@pharmdiddy5120]

Laundry detergent, dark matter, the biggest mystery in the universe... My missing sock is actually turned into dark matter by laundry detergent! I knew it!

[@silverblank1139]

You are not funny, fat man

[@archaurore3323]

Maybe it quantum tunnelled out of the washing machine (or drier)?

[@DavidVonR]

Laundry detergent will take the dark matter off your underpants

[@Motorfirez]

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 .

[@ozama630]

Great upload 👍🏾 However, Axion laundry detergent should be the sponsor of this video

[@garybarbourii8274]

They could never sponsor dark matter being left behind in your laundry

[@JohnSmith-un9fy]

Dark matter always fades my colors.

[@MP-wg8pd]

"Ten to the power of ten to the power of ten to the power..." I feel like I live in Whoville.

[@timothyswag3594]

"CP Violation" Hehe... That's illegal.

[@avrenna]

This comment right here, officer.

[@azmanabdula]

@@avrenna *Chris hanson* Why dont you take a seat

[@fivish]

Report it to the Jadoon!

[@MrHurricaneFloyd]

The term "CP" was used in physics long before it was used to describe that particularly rightfully forbidden type of information.

[@whimsy5623]

hehee funne

[@grebulocities8225]

I got high and then started watching youtube videos. They recommended me the PBS Space Time guy explaining to me one of the leading theories about dark matter, one that I had tried to understand but never really did. You win, KZbin algorithm.

[@tomkerruish2982]

15:50 Cube root. Space is three-dimensional. 15:54 Taking the square (or cube) root of a double exponential doesn't change it much. E.g., the square root of 10^10^120 = 10^(5×10^119) ~ 10^10^119.7, not 10^10^60-ish.

[@anonanon3066]

Why is this so low?

[@tomkerruish2982]

@@anonanon3066 Maybe I posted too long after this video premiered and so not many have seen it. Thanks for the compliment!

[@trollking202]

but the spac 6 dimensions if am not mistaken

[@sprydog3853]

Thank you, thank you, thank you. I love Matt and the factoid that I can feel my mind expand with every episode of Space Time I watch.

[@nashs.4206]

8:57 you mention here that one of the possible reasons why we can't artificially detect axions is because we can't produce strong enough artificial magnetic fields. However, at 9:37, you mention that CAST uses its own strong magnetic field to convert potentially incoming axions back into photons. How are we sure that the magnetic field that CAST produces is strong enough to convert axions into photons?

[@nafrost2787]

Well he said that nature does half of the work, and maybe because we don't need to invest energy in the creation of axions, we can invest more in just the conversion of them back to photons.

[@Skylancer727]

He stated the axion may be in a different mass range than expected. As such, CAST would need to be tuned to find them which is a costly process as you need new wiring and sensors for each mass range. It's the same thing as why LIGO can't detect just any collisions and why we are building bigger interferometers.

[@garybarbourii8274]

It seems like the creation side would be easier to tune. We could measure the total energy absorbed by the metal as we tune the magnetic field, looking for a dip in energy representing the conversion of photons to unabsorbed axions.

[@sc0or]

Gary Barbour II I didn’t hear what must be an energy of photons to convert them into an axion, but heard “a fraction of electron mass”. That could mean that we can observe relic photons passed nearby a magnetar. We know for sure a deviation is about 10^-5K. Any evidence of the conversion must be easily detected.

[@Carrotsalesman]

"How are we sure that the magnetic field that CAST produces is strong enough to convert axions into photons?" They're not sure. They're just trying their best dude.

[@TheAliceQuo]

"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 😅

[@_xplora_9374]

Hey, I believe that ghosts are made from axions. There, that might take any negativity away from u and on to me 👍

[@_xplora_9374]

@Zenothys that's quite an interesting theory, especially when considering the level of vibration used. It doesn't quite explain what I have personally experienced, but I'm very open minded in science and anything else for that matter. Hence I'm watching about axions 👍

[@OculusOfficial]

I like that the theory side of these very complex subjects is "easy" to understand and really illustrates reality in a beautiful way, I find the idea of particles being wavelengths in different fields to be really interesting but I could not imagine actually formulating maths to describe these ideas.

[@pizzamandhx]

I feel like sometimes the " ...spacetime" suffix is forced. Today it was much more elegant. Bravo!

[@RME76048]

For a moment I thought it was "axon" and thought, 'then the antiparticle would be a dendrite?'

[@fghsgh]

axon -> axion dendrite -> dendri-ite (pronounced dendree-ayt)

[@RJ-rf8fu]

@@fghsgh : ...Making the supersymmetric particles the sdendriite and the... saxion?

[@tugbatok9008]

this channel makes me wanna cry but also gives me an immense joy at the same time

[@Bassotronics]

I sometimes think that when a photon is produced, it’s non-electromagnetic counterpart the ‘Axion’ also gets produced with it. Massless, undetected but gravitationally inclined due to its mere existence.

[@adamk.4583]

If it's massless, it can't exert a gravitational force

[@Bassotronics]

@ *Adam K.* Tell that to the photon which in massive amounts turn into a Kugelblitz or however you spell that.

[@adamk.4583]

@@Bassotronics That's when energy is converted into mass via being concentrated enough. It's energy under very specific circumstances. Light on its own has no gravity.

[@moosemaimer]

In classical Latin, C is pronounced as a K. Remember, English is three languages hiding under a trenchcoat pretending to be an adult.

[@user-pp6wy9tb9j]

_"To Always go full N.E.R.D. or to Never go full N.E.R.D.?"_ _- and other seemingly absolute-therefore-false propositions_ (according to minds of a finite existential experience that is)

[@mbabaneamputee7725]

Ya never go full nerd everybody knows that

[@DennisMoore664]

​@@mbabaneamputee7725 Your comment m-m-m-mmm-m-makes me happy.

[@andromedanative6677]

Love nerds.

[@Vertolot]

Wow! Even though, the Consiousness influencing QM video is more to my liking, I am glad I did not miss this one. I went in it without a clue what an Axion is, but your explanation with the graphics was top notch. If only i was a kid way back in school, your content is really inspirational.

[@NewMessage]

I'm just waiting for them to discover the particle that makes sure all this is so overly complex, that the math seems tediously intractable, and mind bogglingly confusing as a whole for us average people. I hope when they do, they call it the Vogon.

[@kieranh2005]

In triplicate

[@BaronVonQuiply]

It would likely be a weakly interacting, low-mass, neutral particle with an affinity for poetry.

[@LithicMetals]

Well done Matt, very concise... so many great concepts packed into this amazing lecture.

[@jv8462]

"That thing Newton wrote" is a weird way to pronounce "Opticks"

[@charlieangkor8649]

i knows some Opticks Tricks. particularly, how to shoot a 10 Mbps full duplex Internet connection over 1.4 km using only a single high output red LED of the type used in car brake lights, in a DIY way, building the machine in a garage by inexperienced people.

[@davidkeen9016]

That's how we say it in Australia. You mean, you say something different in your country?

[@Sci0927]

do you mean: optics

[@null-0x]

​@@Sci0927 No, Newton's book on Optics is called Optiks

[@CLipka2373]

@@null-0x _actually_ it is called "OPTICKS: OR, A TREATISE OF THE REFLEXIONS, REFRACTIONS, INFLEXIONS and COLOURS OF LIGHT. ALSO Two TREATISES OF THE SPECIES and MAGNITUDE OF Curvilinear Figures."

[@stefanschleps8758]

PBSSpaceTime always produces an in-depth understanding of the fundamental methods in which our universe functions. But sometimes you hit the nail on the head in such an unerringly correct fashion that the episode sinply outshines other attempts by our peers in the fields of physics. This episode is such a one.Thank you. Bravo. Well done by the crew. Kudos to you Just remember, observation causes effect. Getting around that is next to impossible. But embracing it might just lead away from it. See you on the flip side. All the best.

[@motor-head]

You might want to re-evaluate your relationship with Nord VPN given their recent difficulties and their shady response to those difficulties.

[@tarekwayne9193]

In any event I was going to say that no product exists that can totally protect you from prying eyes. It's a mathematical impossibility.

[@motor-head]

@@tarekwayne9193 Nord VPN recently had a massive security breach and then tried to deny it. When that didn't work they downplayed it. When that didn't work they finally admitted what had occurred. Very shady way of handling a security breach. Nobody expects a VPN to totally protect you from everything. What I do expect is for a security related company to handle security breaches openly and honestly which is pretty much the opposite of how Nord VPN handled theirs.

[@tarekwayne9193]

@@motor-head I'm sure they'll lose and have lost a lot of business.

[@punkonthego]

Motor Head VPNs aren’t even a security tool. Https encryption already protects against middle-men which is what NordVPN claims they protect against. VPNs are only really useful to convince websites you have a different IP address and/or mask your current IP address. Edit: They are also useful to mask the name of the website you are going to from the ISP. ie. If you want to access something censored in China or torrent stuff without your ISP’s knowledge. Both are fairly niche uses that if you are in either situation, you already know why to use a VPN.

[@parnikkapore]

I only open a tunnel if I'm looking up something really lewd (mostly because of its bundled browser) or want to access something as another country (darn YT country blocks)

[@rowanbirch5391]

Matt's turning into a legend. Great job again.

[@BothHands1]

while i saw and liked this video four months ago, i was directed here once again by the wonderful person anton petrov, who reported today on a new discovery seeming to give credence to the axion's existence. it use i think a 10,000 ton tank of liquid xenon, and they had far more detections than theorized. there are several other explanations, but the axion seems to be far and above the most likely answer. i would love a followup to this video that includes these new observations. but i'm thinking you'll probably give it a few months for confirmation of the data before making a video. still, can't wait to find out if we've finally found dark matter.

[@betsapp8501]

Anton is so wonderful 🥰

[@zertilus]

3:36 okay wow, the strong CP problem really sounds like the intersection in which we need to keep a very close eye on. Our error, our missing connection, lies somewhere in the maths which cause this mismatch. I absolutely love it! I almost want to go to college to learn everything about these problems, just so I can help figure it out. It's so exciting and enticing, to see things like this unsolved to this day

[@armandsantiago3654]

I thank God for people that love physics. I most certainly wouldn't be able to dedicate a lifetime to it. Keep on making discoveries.

[@feynstein1004]

That's the benefit of sexual reproduction, my friend. Diversity in a population. It ensures that while everyone is similar enough to be able to reproduce with each other, everyone is still somewhat different from everyone else. And so we have physicists, musicians, bankers and so on. But I guess economic growth has played an equally important role in it too. I mean, if you have to spend most of your time hunting or foraging for food, you're not going to have much time to think about physics. We're really lucky that we don't live in a time like that.

[@pipari21]

Why would you thank god for the efforts that people are doing? Just thank the people directly. Also, which god? One of those paradox gods or the more "sensible" ones from ancient religions like animals or trees?

[@feynstein1004]

@Eero Huhtamo Damn, mate. Don't be that guy. It's just an expression 😂

[@mizzshortie907]

Love just getting home from work and binging this channel

[@RichMitch]

Back here from Anton Petrov. *hello wonderful person*

[@neropanti9702]

Rich Mitch same here, thanks to wonderful person Mr. Petrov.

[@tiborbogi7457]

Me too. Now I get deeper explanation, so my un-understandig is way deeper. So I am deeply happier. I became a nerd? :-) ;-o

[@manjsher3094]

This is not the place for that kind of commentary.

[@RichMitch]

@@manjsher3094 wot

[@manjsher3094]

@@RichMitch Matt O'Dowd channel, let's not let channels cross. May end reality as we know it.

[@DingBatDaniel]

Saying "Principia Mathematica" wrong but nonetheless getting the information across > Saying "That thing Newton wrote". The channel is great because it teaches. Do not stop teaching to please egos.

[@synapticimpulse7585]

I'm watching this with my cat Lenny right now... and Lenny is like: "Duuuuuude! This is deep!"

[@MrV1604]

I literally had an ad of a washing-up detergent play at the beginning of the video!

[@ajronmejden]

Hey there! Amazing show, keep it up, guys. I'd want to clarify one thing, though. In Polish, the letter 'W' is read/pronounced just like the letter 'V' in English (there's no 'V' in the Polish language'). So Frank Wilczek's last name should be pronounced just like you'd pronounce the English name 'Vilcheck'. Have a great day, science buffs! ;P

[@Jehannum2000]

Is there an English double-u sound ("wah") in Polish? If so, what letter is it?

[@ajronmejden]

@@Jehannum2000 Actually, there is! And it's a letter which, in turn, doesn't exist in the English alphabet. And it looks like this: ł I hope it displays on your screen properly. Sometimes 'exotic' fonts don't. But yeah, when found in a word, this letter is read like the English 'w'. Hope this helps :) Have a great day!

[@Jehannum2000]

@@ajronmejden It did display correctly. I have seen this letter in Polish text. I never would have guessed it sounded like W!

[@ajronmejden]

@@Jehannum2000 Great, now you know :)

[@koshaku]

Hey! This is the stuff I am researching right now for a Undergrad presentation. I love this stuff so much.

[@kamalkhan5305]

Are Axioms Dark Matter ? Maybe ! I like Matt O'Dowd's presentations.

[@olandyurai5437]

I am so happy I found this channel! Fairly sure I've watched every video twice and some of them 10x!!! I'm constantly pausing and going on a google wormhole lathered in critical thinking lol it truly gives me so much joy that words fall short!!!! Love that I can still watch PBS just like when I was a kid!!!

[@Uhlbelk]

The strong CP problem has a completely different meaning on the internet.

[@ZomB1986]

PhpBB's Control Panel is broken again! (and I knew a forum where they renamed it "Captain Picard")

[@robertstevensii4018]

Epstein something something something

[@Potoum]

Cheese Pizza problem?

[@tnspnk3]

Yeah. CP symmetry might be the title of a particular type of fetish video. :)

[@lartylab3391]

Congrats! This exceptional lecture indicates that you (unlike many others) really understand what you're talking about.

[@geekjokes8458]

I've been thinking about... kind of a similar idea behind the theta field: a bunch of constants dont actually seem to be well, constant - what if they are fields themselves? All of them?

[@BenoHourglass]

Then the universe as we know it could just fall apart at any time, I guess.

[@geekjokes8458]

@@BenoHourglass well... it's not a novel idea, vaccum decay is a known possibility (really unlikely but not stupidly so)

[@grebulocities8225]

What if it's just fields all the way down?

[@geekjokes8458]

@@grebulocities8225 what would that even mean?

[@BenoHourglass]

@@geekjokes8458 It's a take on "It's turtles all the way down".

[@krypton9984]

Genius. I pareticularly liked the answers to questions, but the whole thing was just gorgeous.

[@TGNXAR]

"If you're gonna nerd, nerd all the way." Translation: "GET ON MAH LEVEL!"

[@robnolte2547]

I'd be curious to know more about how axions could fit within the framework of what we expect of that as the source of dark matter. Could that help to drive additional experiments to confirm or deny their existence? Great episodes always PBS Space Time team :)

[@iainballas]

Next vexing question: Where did every 10th frame quantum-tunnel to? Srsly, I think the framerate on this video is a bit janky.

[@kukulroukul4698]

no is not

[@sogerc1]

Or maybe your device installed some updates while you watched the video.

[@tehbonehead]

CP violation causing a quantum tunneling effect. In short, DARK ENERGY.

[@robbradley1337]

Yep. It looks like a slideshow.

[@ShubhamRaj-mu8ol]

Maybe, just maybe a very rare quantum phenomenon occurred that converted all the photons from every tenth frame of the video you watched to axions. Probability might be extremely small but still greater than zero😎

[@dr.v645]

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

[@RolandTitan]

"Why not nerd all the way" i legitimately laughed. Thank youm

[@robertschlesinger1342]

Excellent video. Interesting and informative. Max Tegmark has authored some relevant papers. And thanks for the reminder to head out to buy some Axion!

[@SirAlanClive]

Phew, just in time - thought this was due yesterday? I was going into withdrawal there!

[@JackDespero]

I can vouch for the fact that Axion comes from the detergent. At least according to Wilczeck. He said so in a plenary talk in my research institute related to time crystals. He said that the name sounded very cool and he swore to one day give it to something. Apparently he had to invent some BS post event explanation so that the editor would allow such name, so something something axis something something, axions. He also said that we should be thankful, because the name that other people wanted to give them was pretty bad (I cannot remember it at the moment, but I remember thinking that it wasn't as cool as Axion). Thankfully he managed to convince everyone on the new name.

[@mysimpletoon]

Can you imagine how amazing it would be if this turns out to be true? If we perfect the technology, we could create axion telecommunications. You could send out a radio signal that gets turned into axions and then have a receiver that turns it back into photons and because axions can pass through everything you would get a zero interference signal.

[@b43xoit]

Hmm. Why not, if the conversion can be mastered. Hand it a modulated stream of photons.

[@Nurr0]

I understand less than I'd like of this channel's content, but jeez you do incredible work. I love your work.

[@arkadryan7484]

"That thing Newton wrote" ... I LOVE IT!!!

[@AnimeShinigami13]

Physicist: I sense a disturbance in the forces! Axion: Come to the dark side! of physics!

[@emilev2134]

Thanks for the amazing content! On the Penrose diagram, is the «infinite space» from the right corner different from the one in the left corner since they don't represent directions but rather space in itself? Like the infinite past and infinite future look intuitively different but not the «spaces» corners, are they in fact the same corner? Also, could we be in a black hole right now and what we perceive as time would in fact be that space flowing in the direction of singularity?

[@trollking202]

Your close keep at it

[@edmundlee4087]

Thoroughly impressed with this video, one of the best.

[@devrim-oguz]

I'm so early that the video is at 15 FPS. Wait a minute...

[@chadbaptiste4227]

The day Revolver Ocelot asks a question to SpaceTime, you know things of slowed down on the battlefield.

[@nafrost2787]

15:50 don't you mean the cubic root because volume is proportional to radius cubed and so radius is proportional to volume to the third root?

[@tomkerruish2982]

Exactly. However, it doesn't matter much, as the square root of 10^10^120 is ~10^10^119.7, while its cube root is ~10^10^119.5, not 10^10^60-ish as he said.

[@RobinDSaunders]

Also, all this is assuming that space on large scales is roughly flat. If it has negative curvature the distance can be much lower, although still far outside the accessible part of the universe.

[@nafrost2787]

Are you talking about non euclidean geometry stuff? If not than about what? If so than what kind of proportionality is possible in non euclidean geometry?

[@RobinDSaunders]

That's right, space in general relativity is curved not flat (non-Euclidean), but on large scales the curvature might average out to produce something that's roughly flat - or it might not. Some previous episodes go into more detail on this. If, on large scales, the curvature of space is negative and roughly constant, then on those scales the volume within a given radius is an exponential function of that radius, instead of being radius to the power of dimension as with flat space. In principle you could have something in between, such as an effective power law where the power (or "dimension") gradually changes between very different length scales. For example, some approaches to quantum gravity suggest that spacetime could be "2D" on the very smallest scales.

[@speedplane]

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?

[@jessstuart7495]

Could you do a video on quantum spin and relativity, and how spin gives bosons and fermions different properties?

[@danchisholm1]

I typically understand less than 2% of this show. but am addicted and have watched almost since its inception.

[@mozkitolife5437]

Me: aha, hmm, aha, yep. Nope, don't get it. Basically watching it to hear him say spacetime at the end.

[@Carrotsalesman]

He gets a lot of that comment haha. Maybe just try and break it down for yourself after a few watches if you need. It's especially difficult if you haven't seen the videos he references, but binging them can help get you an overall grasp of the big picture, which in turn will help ya at least follow the concepts he proposes if not the math. He's actually really good at explaining things I reckon. I have a lot of "wow, yeah that's awesome, I get it" moments.

[@matthewcreaks2147]

For me even if I don't understand half of it, I still find it super interesting

[@willd4686]

It's okay to not get it. I sure don't. I'm a computer programmer and it's taken me years to get to the point where I understand enough of the fields terms that I can learn higher concepts. Just keep trying and you'll slowly gain an understanding. This guy's probably been to school for this stuff. I like to rewatch / relisten to videos and podcasts. Helps me pick up what I may have missed.

[@robertschlesinger1342]

Excellent video. Many papers covering the video topic may be found at arXiv.org .

[@TheVergile]

science: we found a new particle/force/field/effect/metal genre science: is it dark matter??

[@mpeg2tom]

Principia was probably called “princhipia” by Newton when it was written. In Classical Latin, "c" was always pronounced as "k". Since Medieval Christian times, the pronunciation of "c" before "e" or "i" became “ch”. Only in the 19th Century did Latín scholars outside the church go back to classical pronunciation.

[@clueless4085]

Always wondered about this. Cool info!

[@user-pp6wy9tb9j]

InB4 *The Axion Axiom™*

[@recklessroges]

Nicely played, (you beat me to it.)

[@themoribundapathetic4530]

y e s

[@gregmerritt9366]

The aneurysm trying to understand the subject matter was a small price to pay for the epic pedan call-out at the end.

[@grinians]

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.

[@seven9399]

👌🏾

[@fghsgh]

In classical Latin, yes, but Newton didn't live in 100 BCE.

[@mad-marc90]

Please update the „Space Time!“ playlist. I need it to sleep. Thx! You are great!

[@hyperedwin]

I love this show! Thank you!

[@sebastianeleven3634]

Me too!

[@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!

[@garethdean6382]

*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!'

[@weylguy]

@@garethdean6382 130 years later, the aether theory is still awaiting confirmation.

[@garethdean6382]

Pretty sure it's been solidly disproved. But hey, flat Earth has made a comeback too.

[@feynstein1004]

Wow, so many new particles to discover. We need bigger particle colliders 😂

[@Poultryphile]

Would the duplicate universe have a duplicate Matt presenting another, equally awesome, Spacetime show?

[@earth14rocco36]

Short answer: maybe Longer answer: how much infinite time do u have...

[@MrMakae90]

I want to live inside PBS Space Time. No better content for physics online.

[@whheaattzmayne3183]

When you say "to the power of" more than once for the same number, I feel nauseous.

[@theonlytrue8t88]

When I watch PBS SpaceTime on Valentines Day and am sleep deprived, I Write stuff like this: -Quantum Love 0- -Time... to travel „You are not here!“ says the voice from the Navigation tool, while marking my position with an X. „Typical...“ I sigh so loud my ears might start bleeding. So neither there I am... Just lost in a time between the spaces. Remembered only by future dreamers long forgotten. They look like you and I, in the Review mirror of my Not-Delorian. Dancing in the Starlight, that in the end might just have been an incoming truck. I curse causality for making time as it always has been. No chance for us pushing further to go back and help you against whatever came your way. Fixing your past before you would have known that it would break. So you would not be scarred by the sharp edges. Even if this means making me obsolete in your life. A footnote in the diary you then never could have written. At least like this, I could sleep in knowledge of you never having loved me to begin with, a price that's worth to carry with me. Alas... not even my mind belongs to me. So how could I change the past by going forward on this path of shattered chances? How much I ever wished your tears would flow backwards, to turn your frown upside down. It was never meant to be. My rage without a target to hit. Nothing to kill but time itself. This goal is just unreachable, like a Star that explodes backwards in Time. So vast and simply... impossible. I cannot accept these facts and keep fighting against a past where I am, Not as now I will never be... ...and you not even known to me. Still: I'd burn a Galaxy to keep your pain away. to never let it happen again for a first time. But as all of us: You cannot stop to run. Because time always just falls in step with you. Might as well make the best of it while the metronome keeps ticking. My heart beats 32768 times a second. So by all that it has done, my heart should be; with all the rights of Mass/Matter conversion, just be stone. Your presence softens it a bit. By bit, by bit, by bit. Trying to change the past is a goal just made for fools and errors. To shape the future by the Actions in the now is a task for heroes. With a sense of wonder, how you ever got so strong. Not wanting for the past to change at all. Just packing your Backpack on your back to never look back. I focus my Rearwardview on my Backtracking Machine.Put it from driving backwards once more and never, into reverse to return from the past into the now. To see my yet. And all that is; still, not done in it. 88 miles per Hour into my here, seems so slow compared to you. Walking with confidence inside yourself, while I stumble between the strings of a past reality. No one knows what path you will choose, once a fork has been presented. Your lifepath is like, the most beautiful double slit experiment! But am I, with you entangled? Your Love, in some of the times. just a particle. Cannot touch it, to my dismay. Sometimes your love was, and may be, a wave sweeping me away. I do not mind. As long as you find laughter on your way.

[@briancrane7634]

I need to dig a few tons of salt out of my personal salt-dome deposit to take with these new ideas...

[@Jossandoval]

So, if the Axion actually exist, you would be left... Salty?

[@polwayirbla]

Two questions: 1. You talked about mainly two experiments: the light shining through a wall and the helioscope. Why did you not comment on axions being generated at colliders? Is the interaction too small? 2. In the limit plot you show at 10:50 only the coupling to photons is scanned. Why not consider the coupling to gluons, quarks?

[@garethdean6382]

1.) The interaction would be quite common, but very hard to tell apart from the creation of high energy photons like gamma rays. A collider can only really identify a particle if it breaks down inside one of the detectors in a unique manner. 2) The photon-axion conversion is the only really simple reaction, so other couplings are ignored. They exist but don't really impact what we can look for and don't matter if the photon-based experiments find nothing.

[@fiskfisk33]

ugh NordVPN...

[@FuttBucker42069]

fiskfisk33 it’s what helps keep the show alive 🤷🏻‍♂️ I like learning. Don’t you?

[@Balorandy]

@@FuttBucker42069 they're not a reliable service. they had a data breach recently

[@TNThot]

@@Balorandy which also proved they dont store data. I would argue it makes them more trustworthy than any other major vpn provider out there.

[@LeonMRr]

Matt, at 15:51 I believe you meant that the distance would be the cubic root of 10^10^123 (or 90), which would be 10^(3,33*10^122 (or 89))-ish times the radius of the observable universe, which I believe means Rick has invented just an ultra-overpowered teletransport gun.

[@nosuchthing8]

Wow, what a trip. Have to review this again. Love the fact that a constant can be transmogrified into a field, and then call into existence a particle because thats how fields and particles work.

[@georgethompson1460]

Could make for a cloaking device, turn the light you emit or reflect into invisible axions.