Sound Waves from the Beginning of Time

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With the subject heading: Negative Mass Challenge Question
Invisible to the naked eye, our night sky is scattered with the 100s of billions of galaxies the fill the known universe. Like the stars, these galaxies form constellations - hidden patterns that echo the reverberations of matter and light in an epoch long before galaxies ever formed. These are the baryon acoustic oscillations, and they may hold the key to understanding the nature of dark energy.
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Previous Episode: Why String Theory Is Wrong
• Why String Theory is W...
Hosted by Matt O'Dowd
Written by Matt O'Dowd
Graphics by Luke Maroldi
Directing by Andrew Kornhaber
The field of cosmology - the study of the universe on its largest scales - was once the least precise in all of astrophysics. The impossibly vast distances made accurate measurements near impossible. But as our telescopes and our techniques improved over the past few decades, things are now different. We live in the era of precision cosmology, in which we know to stunning detail the properties that govern the very birth, evolution, and end of our universe. We talked about one of those properties in a recent episode - the Hubble constant - and about a growing conflict in its measured value which hints at strange new physics. Today we’ll talk about another measurement that may help resolve this crisis: the baryon acoustic oscillations. They the fossils of the first sound waves in the universe, imprinted in the distribution of galaxies on the sky. And in these patterns we can read the expansion history of the universe.
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سلطان الخليفي

[@jureculic9737]

Hi I am 13 year old from Croatia and I want to thank you for teching me all of this, I want to become theoretical physicist and if I do it I want you to know I am very thankful♥️♥️♥️

[@pere3965]

Follow your dream kid 👍 Good luck.

[@zorgius]

Juki Cuki Respect.

[@You-are-right-but]

Physicists change the world and our understanding of the universe. You will do this too. 🙂

[@FilosSofo]

Fight for this dream with all your being. Fight until you are out of strength, and then fight much, much more. For us, seekers of knowledge, the light of wisdom is the light of life.

[@TWJfdsa]

Keep in mind what these videos teach is not necessarily correct there are many competing theories. Check out the Thunderbolts project. Good luck

[@femmedracula6857]

About that last comment - the fact that you know this material inside and out and are able to present it in relatively accessible language is why this is in fact my favorite KZbin science channel.

We can't tell whether he knows the material inside out, at least not from the video. An actor can spout a script just the same.

[@Mohammad__M__]

@ I wonder why we have professors at university instead of some actors. much more time and human resource efficient!

@@Mohammad__M__When I was at uni the professors also answered ad-hoc questions. But you are right that for the bulk lectures you don't need a full on professor. You don't even need an actor. A video recording of a professor, or even just a book can be good enough for that part of teaching. The stuff we can't replace as easily are the tutorials. But those are usually run by teaching assistants.

[@toesauce1665]

@ the host is an astrophysicist or cosmologist, one of those two

[@39anonim]

"Regular sized Tyrion Lannister" really made my day :D

[@KnightsWithoutATable]

And what's wrong with looking that way?

[@bentopalchemistfranklin7797]

@@KnightsWithoutATable Did he say something is wrong with it??

[@KnightsWithoutATable]

@@bentopalchemistfranklin7797 It could be taken negatively if it is referring to the character in the book since his nose gets cut completely off during the battle at the Mud Gate instead of just a full length cut across the face.

[@Sam_on_YouTube]

@@KnightsWithoutATable It's clearly Peter Dinkledge that he looks like. The character in the book has two different colored eyes, half a nose, and overall is just a mess.

[@beskamir5977]

Yep, now that he mentioned it I cannot unsee it.

[@Hauthorn]

I think my favorite thing Matt ever says is "In reality...". It means so much more in this context than its usual every-day use.

[@poppers7317]

In space, no one can hear you scream. Baryonic matter in the early universe: "Hold my beer!"

[@tomc.5704]

And for thousands of millions of years, they went unheard. T'was only long after those baryons had collapsed into flaming orbs of fusion and inescapable gravitational singularities that anyone heard those famous last words.

[@uniisnor]

@@tomc.5704 First words, the universe was a baby after all.

[@thehellyousay]

🤦

[@thehellyousay]

@@uniisnor *belch* "wazzat? Waddafuck?... Aw shit, waddafuckin mess! Honey....?" The real first words because the universe is just some inter-dimensional drink's diarrhea.

[@butterworth1359]

and Saturn. have you heard the sounds coming from Saturn? It's... Quite terrifying..:(

[@IuliusPsicofactum]

We can say they have a very sound model for the galaxies distribution.

[@KrisCadwell]

I'm calling dibs on The Baryon Acoustic Oscillations as a band name.

[@TheCimbrianBull]

If it was an Australian band "oscillations" would be "Ozcillations"!

[@Pining_for_the_fjords]

@@TheCimbrianBull That made me laugh 😂

[@TheCimbrianBull]

@@Pining_for_the_fjords My pleasure. Cheers, mate! 😀

[@SLAUGHTYBAUDFAUST]

That sound very much like a prog rock band name

[@jackassplus]

Only if someone in the band is named Barry.

[@nolanwestrich2602]

I was in the middle of another video, but then Space Time uploaded.

[@BulmaSoft]

Me too.

[@SquirrelASMR]

@@BulmaSoft then what!

[@Haplo-san]

lol, same. I was watching the video about Planck's constant.

[@CamTechBricks]

+1

[@wigleboy]

I reference the old episodes as well as rush to see the new ones.

[@TheExoplanetsChannel]

*Congratulations for reaching 1.5 million subscribers!*

[@Dr_Kenneth_Noisewater]

Regular-sized Tyrion Lannister got me. 😂 Well handled.

[@Andyg2g]

This is my favorite Space Time episode yet. Great from beginning to end. The final comment at the end got me lol

[@frederickoscarrobinson3933]

That cracked me up also.

[@Thulahdanlauss]

Thanks for making so much sense, i'm actually starting to understand what the CBR actually is and what it means to physicists. From someone without any science background, you have my thanks Space Time :D

[@johnmontgomery560]

How confident are we that the fundamental constants of nature are the same at every place and at every time ?

[@ericeaton2386]

As confident as we can be! Every observation ever has indicated that. Since we're not omniscient of course, it's possible that they are not, and there are actually several theories that contemplate changing constants. But so far literally all of the evidence is in favor of their universal consistency.

[@klumaverik]

How many times has he said "Forged in the first minutes after the big bang." Throughout all of PBS Space Time.

[@Vulume]

I mean those were the most important moments in all of, space time.

[@donaldharlan3981]

OMG it means he likes young ones, because the other hosts like dark matter!

[@demandred1957]

I don't think he ever exactly repeats the outro sentence. It's usually a on topic, random, sentence that ends with "space time".

[@BenjaminCronce]

I can't remember, but my liver does

[@Wallach_a]

Someone post a supercut and link us please.

[@dazzassti]

Can you imagine having a beer down the pub with Matt. Lol he'd never get home. Top bloke.

[@LaunchPadAstronomy]

Another brilliant production. I want to be like you guys when I grow up.

[@SolaceEasy]

Peter Pan

[@grahamhill676]

You made it man

[@ranieremenezes3897]

Hi Matt, I have to say it was amazing. I'm in the half of my PhD in astrophysics and BAO was always an issue for me. You make it so simple. Thank you. Missing Space-time journal club. Cheers

[@TheAngelsHaveThePhoneBox]

Wow, I'm so early that by the time you read this comment, it will be redshifted into microwaves.

[@kukulroukul4698]

:)))

[@koenvandamme6901]

*puts frozen dinner on phone screen displaying this comment*

[@SrmthfgRockLee]

;о

[@Raletia]

@@koenvandamme6901 Disappointingly, I don't believe the light coming from his sentence would generate enough microwaves when redshifted to even excite any water molecules.

[@Vasharan]

No fair using a TARDIS.

[@flymypg]

I really love these sequences of chained episodes, each building on one or more prior episodes. It adds a drama all its own, somewhere between a detective story and a love story. The comment coverage at the end really keeps the circle closed and tight, reminding us we're all part of this story.

[@unleashed93]

Can we take a moment to appreciate that a pretty in depth physics channel has 1.5 million subscribers? Momentous in my opinion. Great job Matt and crew!

[@supersonictumbleweed]

Wouldn't trade Matt for anyone :)

[@scudder991]

Love this topic, love this channel, and really really like this astrophysicist!

[@jojolafrite90]

Ha ha. thanks for mentioning J P Petit. Yes it is speculative, but I kind of like the idea. It has a certain elegance.

[@rileythornton2000]

The only thing more beautiful than the ability of astrophysicists to unravel the mysteries of the cosmos is your ability to deliver those understandings to non-physicists.

[@musicisbrilliant]

This guy ends on a savage note! Ha. Love this guy.

[@mauorel]

That's it! Im casting you on my Intergalactic Game of Thrones spinoff

[@Anyox17]

I've been binge watching your quantum physics videos and now I'm literally not sure if I truly exist or not like bro this is terrifying

[@MegaParrotMan]

In quantum physics you both are, and are not :)

[@zack_120]

Now this has become one of my favorite sci channels on YT.

[@AshleyKitto]

Another great episode. Thank you for sharing knowledge made for the lay person.

[@Chisuz]

one of the best episodes in my opinion. such a brilliant piece of science explained so well... love pbs spacetime! thank you for bringing to us an understanding of what theoretical physics has been achieving...

[@pinnacleexpress420]

you think 5:50-7:00 was explained well ?

[@olivercharles2930]

@@pinnacleexpress420 Yes.

[@olivercharles2930]

@@pinnacleexpress420 goofy ahh pfp

[@pinnacleexpress420]

@@olivercharles2930 as if a times new roman O is better

[@olivercharles2930]

@@pinnacleexpress420 It is.

[@RME76048]

Wow. Now *that* was seriously... illuminating. On many episodes of Spacetime I often play it two (or more) times to digest everything, but this one made perfect sense the first go round.

[@nunyobiznez875]

Those sound waves from the beginning of time are actually the sounds of a very loud stoic deep voice, with lots of reverb effects, saying, "LET THERE BE LIGHT", followed by a much fainter secondary voice saying, "...And then there was light".

[@philipmylan5075]

Ah, yes, the baryon acoustic oscillations! I've been hoping you'd do a video on this!

[@laetitialalila7390]

Last time I was this early, sound travelled at half the speed of light

[@phoule76]

haha! (just "sound", like "life", no article b/c it's in general)

[@laetitialalila7390]

@@phoule76 Thanks! It was 1 a.m. and I was really tired, but then, Space Time uploaded!😁

[@immortalsofar5314]

Keep going to a few moments *before* the big bang and you'll hear "A-one, a-two, a-one-two-three-four!"

[@chrismcgarry3160]

<a href="#" class="seekto" data-time="354">5:54</a> Waves Freezing as Photons Decouple from Matter <a href="#" class="seekto" data-time="593">9:53</a> Retrieving the CMB's Baryon Acoustic Oscillations in a modern Galaxy Atlas!! That Epoch is so well understood! Mind-blowing!

[@leyasep5919]

<a href="#" class="seekto" data-time="907">15:07</a> please make an episode about all the crackpot messages you receive !

[@Niwles]

I really want to see that. Some people writing paragraphs to prove how they are smarter than Einstein, Feynman, et al.

[@leyasep5919]

@@Niwles or just misunderstanding basic physics laws, mixed with bad maths :-P

[@mynameisee333]

Greatest. Narrator. of all time.

[@dillonaumiller]

Watching Matt reminds me of watching Sagan. You can tell he has so much genuine interest/awe/enthusiasm for what he's talking about; the inspiration is contagious.

[@alanjmcq]

This was my favorite so far, because I love music, and it's great to hear about the Big Bang's sound. I had no idea the speed of sound could be so FAST!

[@DerpyBerb]

Proof that the universe likes every galaxy... it put a ring on each of them.

[@richarddeese1991]

This is one of the most head-spinning things I've ever seen or heard of. Wow! It's one I'd have never, ever thought of! That's the beauty of science: it provides clues that make us ask questions we'd otherwise never thought of. Incredible. Rikki Tikki.

[@juanb890]

Bringing back memories of the old Carl Sagan's Cosmos. Just beautiful and inspiring. Thank you.

[@CitizenSn1pz]

Well done, excellent video. Fascinating that we can see an imprint of something that happened so long ago in the shape of the universe itself

[@TheIggle]

Yo, just wanted to balance out the haters. I find your explanations very understandable, not dumbed down but instead very well paced. Also you voice is literal ASMR for me. Thanks for all your work making these videos

[@pabilbadoespecial]

This is crazy! I am currently doing my undergraduate final year project on this!

[@demandred1957]

Well now you have no excuse for anything but an A. good luck.

[@bryano2130]

Don't forget to properly cite this video lol

[@mahditr5023]

Lucky

[@dasanoneia4730]

i used to think iwas smart til i started following this channel i get about %10 -%20 of all of this yet i keep watching

[@KeithCooper-Albuquerque]

Dasan, I'm right there with ya!

[@demandred1957]

Ditto.

[@Nestoras_Zogopoulos]

We actually retain sth along the lines of 1% - 2%

[@merinsan]

That episode was so cool. Hearing about how a theory hypothesised something, then they found the data to support it is cool enough. When it's regarding the structure of the universe, it's way cooler.

[@SaposJoint]

At about <a href="#" class="seekto" data-time="400">6:40</a> my head started hurting. I truly hope we'll get a more detailed primer on that later. Thank you. Very nice videos.

[@fluxcapacitor]

Why expanding acoustic _rings_ and not acoustic _bubbles_ (more isotropic)?

[@aelolul]

Same reason of when you take a picture of a soap bubble, you see the edge the easiest.

[@fluxcapacitor]

Understood, thank you. But it was a bit misleading, because those "rings" are only a 2D observation with our eyes (like the plane of the milky way in the sky) whereas in reality the sound shell did expand radially as a 3D bubble in all directions, as I thought initially. This is important to point out, as redshift measurements are not restricted to a 2D plane.

[@RME76048]

Good point and observation. The Universe (4D) isn't a collection of ripples in a pond (3D) that constructively (or destructively) interfere with each other. But, I do like the fact that they are truly acoustic waves that at one time had a speed of 0.5c. With the amazingly dense earlier Universe expanding into a far, far less dense one, has anybody looked into Rayleigh-Taylor instabilities in same, especially earlier/denser?

[@lucascerro8189]

Because they chose to use the Z axis to represent amount of mass the clusters rather than using them to make bubbles

[@lucascerro8189]

Also because the “surface” they were drawing on, the CMB, is in it’s essence a 2D map.

[@CarbonFiberSpoon]

I was supposed to be preparing for seminars in probability theory & group theory.. In 17 and a half minutes I swear

[@manjsher3094]

You probably not gonna make it

[@connorschmidt5945]

Hey Matt and friends, thanks for the great videos! I'm a physics undergrad and since I found your videos last year I've watched all of them. I like your teaching style more than classes, so you've been a great asset to my understanding of physics. You guys really inspire me! Thanks

[@cpg100]

There is always something (or many things) I don't understand on your videos, but I keep coming back to them. The thing that puzzles me the most is the doubt between you being a bad teacher or me being a bad student.

[@tomhauer6528]

Three Rings for the Elven-kings under the sky, Seven for the Dwarf-lords in halls of stone, Nine for Mortal Men, doomed to die.

[@Keiran19]

*One ring to rule them, one ring to find them and in the darkness bind them.* Lol I'm glad I'm not the only one who thought of that when I heard rings XD

[@HelgeMoulding]

Nice. But they're only rings if you slice them. They're spheres in 3D space. You knew that, of course.

[@Keiran19]

@@HelgeMoulding Yep, that was clear when he said it, the universe is 3 dimensional after all (if you're not counting time as a dimension, that is)

[@siRrk1337]

fun fact: about half way through the video i thought "that guy looks healthy". tyrian lannister is actually quite good looking!

[@WestOfEarth]

Wow. The creativity involved in using sound waves for independent confirmation of cosmic expansion boggles my mind. Well presented, Matt.

[@will2see]

Great explanation. Thanks! Although I had to pause and playback it several times to grasp it, I got it :-) Now I finally understand what baryon acustic oscillations are.

[@LoverKittey]

46 views, 72 likes, and 1 dislike. HOW COULD YOU DISLIKE ALREADY????

[@achi-leanathlos8376]

It was an anti-vax mommy

[@LoverKittey]

@@achi-leanathlos8376 good point

[@BenjaminCronce]

haters gonna hate

[@aspuzling]

The bump in the graphs at <a href="#" class="seekto" data-time="633">10:33</a> is shown at 105Mpc, but I thought we expected the bump to be at 150 Mpc? What am I missing?

[@NeufeldIan]

The graph shows the original distance at Recombination which has since spread out due to the expansion of the Universe, and the amount that it has spread out gives us the expansion rate.

[@bryano2130]

I was under the impression that it was expected to be at 105Mpc, but even then, on such a large scale, the difference of 45Mpc is probably still within less than a statistical standard deviation. 105*10^6 parsecs is still pretty close to 150*10^6 parsecs when dealing with such large numbers and converting theory to practice.

[@motownprinceton]

I was confused by this too - after some googling it seems like the units given (MPC/h) correspond to something in the neighborhood of 1.5 MPC. Would love a concise explanation!

[@bryano2130]

@Tony Wells thank you, I will name my first born child after you for this.

[@toshiro0o]

Basically, it said comoving distance. Since the measurements of the galaxies that are farther away are from farther into the past, you have to evolve all the distances you obtain forward or backward in time, and bring them all to the same moment. That way you get a picture of the universe at a single moment where you can compare distances independently from its expansion. Depending on what moment you chose, the distance for the bump can really be anything. It only has physical meaning when you know the moment as well, or its corresponding redshift. I assume they mention that in the paper, or there might be some standard choice, like the lss.

[@d-mark]

PBS Space Time is such an amazing show. Mind blowing and fascinating and so well put together. Thank you!!

[@AndrewKimmey]

If you could go back to these moments and listen to the sound waves, they would be like overlapping metallic energetic buzzing sounding like "oooooommmmmmmmmmmmm" - ॐ the primordial sound of creation.

[@fluxcapacitor]

Hi Matt, thank you very much for your honest comment at <a href="#" class="seekto" data-time="963">16:03</a> during an entire minute about the _Janus cosmological model_ by French astrophysicist Jean-Pierre Petit. This is so rare in the English-spoken world to hear about these ideas! It makes me want to translate your whole episode in French language. Will do it soon. BTW, let's say that ALL theories are by essence speculative. Good theories try (and are able) to describe our _physical reality_ (i.e. accounting for observations and measurements) and they also make _predictions_ so they can be _falsified_ (in the sense of Karl Popper). On the contrary, bad theories don't even bother to be falsifiable (there's a lot of them!) or are already falsified. It is the natural cycle for a good dominant theory to be superseded by a better one, someday. I don't know if the Janus model or another bigravity theory will prove to succeed where lambda-CDM will fail (which is quite difficult, as the lambda-CDM model is very adjustable thanks to its various free parameters that can be fudged to stay in accordance with many new observations over time, a bit like the _Ptolemaic Epicycles_ ). But the proof is in the pudding: the Janus model can already account for observations with fewer free parameters and can also explain observational facts the concordance model cannot. Have a look for example at such comparison points in _Astrophys Space Sci_ (2018) 363: 139. doi:10.1007/s10509-018-3365-3 It will be interesting to see if the Janus model has its own explanation for the solid discrepancy between CMB ringing and stellar recession speed measurements, hence in the surprising discovery that the density of "dark energy" may have different values through space and time. Cheers

[@AlcyonEldara]

Could you stop lying please ? "Less parameters". Of course, when you use "variable constants", you don't call them "free parameters". Which is a big fat lie. You need to add a free parameter for the rate of change and assuming A LOT. "Can already account for observations". Another lie. JPP claims to explain everything but always put the "right" numbers (=free parameters, and differents for every "explanation") and sometimes he just claims "my model works" without providing math. He also don't have a CMB or a baryon accoustic oscillation. We don't observe any divergent lensing. And let's not even talk about the dark matter in janus. Dark matter = matter that don't interact with "regular" light. The current model is saying "we don't know what this DM is, so we don't assume anything". JPP add a full set of untestable predictions (interactions, speed of "negative" light, etc), his model isn't even a scientific model. And I am not even talking about how JPP insults everybody who dare to point the flaws in his "model".

[@fluxcapacitor]

Speaking of insulting others, wow. Very constant and distinctive of the despicable French hatred astrocoackroach pack. To every others: let idiotic _ad hominem_ attacks about atypical personalities aside, and focus on *peer-reviewed papers only* I want to thank everyone else in this channel for having shown kind openness and sense of humor yet good critical thinking :)

[@AlcyonEldara]

@@fluxcapacitor Je suis francophone, pas de bol. Et pas loin de la France en plus. Vraiment pas de bol du tout. And yes, focus on peer-reviewed papers only, for an obvious reason : any crackpot can put a non review paper on Vixra.

[@fluxcapacitor]

Indeed Dr Petit never published anything on the viXra preprint server, but instead mainly in peer-reviewed journals like Modern Physics Letters A, Astronomy & Space Science, Journal of Physics Communications, among others. Only these published papers and the maths inside are actually relevant in the discussion, we agree :) As for hobbies, cultural advices, personal interest, conduct and behavior: we don't care, at least for science.

[@AlcyonEldara]

@@fluxcapacitor oh, I get it ! You understand that you don't have enough background on the subject to answer the issue raised, so you change the subject. And you are waiting for ad hominem attacks. Though luck. I was to tak about physics. janus doesn't work. JPP uses the numbers from the "standard" cosmology to match the observations, but claims "my model explains it !". Educate yourself.

[@benwitt6902]

I can't figure out how to turn off my perpetual motion machine.

[@whoojeewrexhan1271]

Try turning it off, and not turning it on again... x

[@GodofAbraham]

I know right stupid Energizer batteries 😡

[@randalmata100]

Q. Are these the same gravitational rings Rodger Penrose postulates are the signature of Black Hole collisions in a previous aeon? His Conformal Cyclic Cosmology. Matt really does a fantastic job explaining, in lay terms, our (sometimes hard to understand) modern science findings. I'm sure his explanations have given many a lay person a deeper understanding of Physics, Cosmology, and Astrophysics. Oh BTW, I think he looks a bit like a younger Colin Farrell.

[@DFX2KX]

That shade at the end... *PERFECT*. A rule of thumb I've always held to when reading some new fringe theory or other: "Does this break the laws of entropy, or otherwise make the Universe violate self-consistency in some way? If so, then buy a salt mine because you're going to need more then just a grain of it"

That background song is amazing

[@evaristegalois6282]

Sorry, I cant hear the sound waves from the beginning of the time because I’m wearing AirPods _Wave check_

[@unknownfury7672]

Evariste Galois I believe they r actually jarpods

[@inquaanate2393]

Oh god, oh fuck!

[@BinkyBorky]

*stares down at the apple user from his PC master race pedestal. Sorry, I can't hear you. The FANboy is too loud ;)

[@JorgetePanete]

can't*

[@tabaks]

An idiotic reverberation imprint comment stream.

[@Revy8]

pbs space time is my favourite channel to fall asleep to at night. The hosts voice is very soothing and the concepts are a bit over my head so my brain just shuts off lol works every time

[@andrewcurry9910]

<a href="#" class="seekto" data-time="229">3:49</a> "Density Fucktuations" You have my attention.

[@zero132132]

An Actor's job is to be mistaken for other people, so I can't help but be amused that many people want to be mistaken for actors.

[@thehellyousay]

Was sarcasm. Is funny ha ha.

[@thomassynths]

Why is the camera so foggy?

[@norgepalm7315]

They recorded him in 240p

[@SophiaAstatine]

Cause physics make everything hot and steamy. Even a recording studio.

[@magellanicraincloud]

Too many unbound electrons scattering light.

[@az09letters92]

They probably filmed in logarithmic colorspace (pro-video methodology to aid post processing) and accidentally forgot to do color grading in post production.

[@kendomyers]

Atmospheric interference? Quantum uncertainty? Aliens?

[@johannesh7610]

It's so exciting to think about the expansion and the early shape of the universe! Actually even more when you imagine it as infinite and therefore not actually changing in size, where just distances increase exponentially and stuff dilutes with the first little wobbles in the immense amount of stuff, that already existed back then, forming into our current universe😊. Keep up the good work, greetings from a german physics student

[@MeissnerEffect]

Such complex matters explained in a way few can! Excellent work as always!

[@androidkenobi]

Congratulations! Ya Made It!

[@Lyle-xc9pg]

You mean into the domain of evil, of youre talkig about google

[@vopall]

That was awesome. Well done presenting it in a way a dunce like me can understand

[@hemantsharma637]

Ancient Hindu scriptures say that in beginning there was Sound, and Sound was the God - Nada Brahma! Watching this with that thought at the back of my mind was fascinating!

[@miallo]

This video is three days late: I had an astrophysics exam on Monday and I have to say: this video made some things clear that I didn't quite grasp in the lecture...

[@ryanburch6308]

Is Matt O'Dowd the product of Nickle Back & Creed have a baby who became a youtube physicist. "Can you take me higher? To the place where blind men see..."

[@WiscoDrinks]

Tyrion Lannister? more like Baryion Lannister... heh. nothin personnel kid

[@anger_birb]

Oh now your starting with the shitty puns get out 😂

[@KafshakTashtak]

Man, that last comment was awesome. You earned it Dr.

[@gandalf_thegrey]

"It disagrees with our current understanding of physics" is an extremely well argument when it comes from an expert, not so much from some KZbin commenter.

[@SupLuiKir]

Under a bimetric universe, where the universe is actually two separate superimposed spacetimes that gravitationally interact with each other, would that allow for something akin to the sci-fi concept of subspace?

[@geoffcunningham6823]

If you are making stuff up, sure.

[@bryano2130]

If you're referring to the idea of superposition, remember, that really only applies to particles on the Planck scale. And even in this sense, there's no in between, hence why superposition works. That's assuming you are staying in the 3 dimensions that we're able to collect data on. However, I think you might be interested in string theory or M theory. This channel has a lot on it, they've even had a few episodes just recently specifically on seeing theory. Conceptually, you might want to read some of Michio Kaku's books or watch his documentaries on string theory.

[@bryano2130]

@Cosmic Rift I think they're basically asking if two parallel universes interacted with each other on a measurable scale, if the rules of physics would be different where they met. Kind of like a venn diagram.

[@DFX2KX]

not in the literary sense, (IE: another 'demension' you can travel through to circumvent light' a la 40K's The Warp or Hyperspace)? No, unfortunately.

[@gonaldocr24]

I only listen to 14 bya old music

[@lastmanstanding5423]

OG hipster...

[@randomuser5443]

Okay grandpa

[@bytefu]

Filthy Frank would be so proud.

[@Hannah-ds2bl]

born in the wrong generator

[@mk2817]

You wouldn't have heard of it😉

[@lucascerro8189]

Wow. I absolutely love you guys. And I’m motivated by the more “mathy” episodes. But THIS kind of content is the mind-blowing, widely-accessible videos that changes perspectives. Also: PBS, you’re wonderful!

[@alpha_mach5049]

"Beyond the worlds vague ghosts of monstrous things; half-seen columns of unsanctified temples that rest on nameless rocks beneath space and reach up to dizzy vacua above the spheres of light and darkness. And through this revolting graveyard of the universe the muffled, maddening beating of drums, and thin, monotonous whine of blasphemous flutes from inconceivable, unlighted chambers beyond Time; the detestable pounding and piping whereunto dance slowly, awkwardly, and absurdly the gigantic, tenebrous ultimate gods-the blind, voiceless, mindless gargoyles whose soul is Nyarlathotep." (From "Nyarlathotep")

[@gamereditor59ner22]

I love space and time with a lot of quantum and astrophysics behind it!!

[@mattko]

Pay no attention to the haters Tyrion.

[@LordTelperion]

Speaking of sound waves, Australian accents are beautiful. Speaking of Australia, there seems to be a mini cultural golden age for them: I've been discovering more and more examples of really good Australian-made movies, TV, intellectuals & educators over the past decade. This could, of course, just be a factor of the internet bringing us all together more than ever before and/or me being late to the party.

[@martinwrene4385]

1.take a step forward from the green screen. 2.light yourself and the greenscreen separately without casting shadows on the screen. 3. If the room is tiny and your still green, consider covering the source of the reflecting green light. 4.consider wearing a shirt that is in contrast to the planned background color. 5. 👌🏻👌🏻👌🏻👌🏻🤗🤗🤗🤗

[@fredobedo548]

Jpp, Jean-Pierre t'as percé :) ;)

[@amedicabg]

Clicked faster than the speed of sound

[@ryancraigt]

Clicked at 99.9999999...% speed of light. Meh.

[@ForevverYoung777]

Clicked at the speed of light to the tenth power

[@JorgetePanete]

in what medium?

[@ForevverYoung777]

Jorge C. M. What

[@DANGJOS]

@@ForevverYoung777 Sound travels at different speeds in different media

[@shmigelsky]

Wow! That is one best videos yet! Please do more like this, that is just incredible.

[@linksysKOW]

Excellent video, boys. I love how in-depth but simple the presenter keeps it. Enjoying the channel a lot.

[@swe3131]

Will we ever hear the first sound ever made in the universe? If so, would it just be absolute silence following that?

[@donaldharlan3981]

yes it is what he said we already know.

[@imaginaryuniverse632]

We hear it now. It's still sloshing. Every sound that has ever been made in this Universe is still in the waves of every atom. All the information in the Universe is in a single sound that can be broken down like a Fourier transform. We have receptors in our DNA that translate the frequencies that we allow in as he was talking about atoms at the 5:30 mark. It's the sound waves from our hearts that create the electronic Torus that surrounds us. It's the Sonic wave, caused by the cavitating heart as a one way valve in a closed system, that causes an attractive vibration in the structures of our cells, or I think the mitochondria that are in our cells as friends in cooperation, to pull electrons from protons to create a pressure gradient, amongst other things, that powers things and moves things along. I don't know how they came up with the cartoon to illustrate the electron supply chain and they admit that they can't see that closely but didn't say then where they got their reasoning. I'm always skeptical of cartoon biology and cosmology but I feel like that got it right because I recognize the design from Tesla and another unknown architect of ancient times.

[@SolaceEasy]

No, someone always passes gas after we say Om.

[@imaginaryuniverse632]

@@SolaceEasy The worst is when the gas emerges from the silence.

[@mistamac6509]

lets go matt, flex on them haters

[@rutikjadhav]

Hey man Thank you for such amazing content. I have been watching Space Time for 2 years now. I am 17 now. I just want to tell you all that I thank you for quenching my thirst for knowledge. I can't get through the week without my weekly dose of Space Time. I wish y'all good luck and just wanna tell you that "This is the best channel across ( in Matt's voice) SPACE TIME"

[@1ConscienceSociale]

Janus model in french : fr.wikipedia.org/wiki/Mod%C3%A8le_cosmologique_bi-m%C3%A9trique

[@marcoskunrath5914]

I don't want to be pedant, the following is a sincere question; they are spheres, not rings, right?

[@Bodyknock]

I think they are galaxies that form along the intersections of two spheres of sound waves. Two spheres intersect in a circle and galaxies tend to statistically clump in those ring shaped intersections.

[@marcoskunrath5914]

@@Bodyknock but in that case, the outer ring radius be should inversely correlated to the distance between two "epicenters", rather be exactly 150 Mpc from the center.

[@LuisAldamiz]

My best guess is that you're probably right but that we see those spheres as rings because we lack stereo vision of the universe: for us it's "flat" and we can only see depth with great technico-theoretical effort and even then our depth (Z) is not different from time (T) because of the huge distances involved. So it's rings for us but maybe if we had "godvision" and we could pan around the Universe we could see them as spheres.

[@Bodyknock]

Marcos Kunrath Where two pressure spheres of equal radius intersect you have relative clumps of material in a ring around the epicenters of both spheres and the distance from any point on that ring to either center point. Where a third sphere intersects both of those two you’ll additionally get two points that have the largest clumps of material and those points will be exactly the radius distance from all three sphere intersections, and so on. Thus the largest spike in material density that’s not an epicenter would be found where lots of spheres of equal radius are intersecting at essentially one point, and that spike would be the radius of those spheres distant from all the epicenters.

[@marcoskunrath5914]

@@Bodyknock Now it makes sense. tank you!

[@chuckrittersdorf]

So when will we get space battles with laser beams that actually make sound?

[@infamoussky22]

Gotta heat the universe up again

[@bryano2130]

@@infamoussky22 lol and when we find a way to make lasers on the visible light spectrum have enough energy to put holes in solid metal in the time span of nanoseconds. That also make sound.

[@zakyrath]

Well depends, Star Wars and Star Trek weapons were plasma based not laser based I thought. Star Wars I know for sure is plasma since it uses tibana gas superheated to a plasma in blasters

[@vickymine3203]

Movies depend on “suspension of disbelief” or let’s ignore science for the sake of entertainment. If films had to adhere to the facts, we would only have documentaries & not enough exploding cars.

[@tomc.5704]

It won't be quite as satisfying, but we could just make up a model for how lasers "should" sound and add in that sound effect whenever we fire a laser. Each color, intensity, and size can have its own distinctive sound. At the very least, we'll keep adding on these sounds for the space battle documentaries.

[@AlexandruJalea]

It's like an unknown force that can be measured. Some sort of dark force, that stops you in the middle of a sentence. Because there is a new upload that you cannot miss. Thanks for the work.

[@berendharmsen]

I enjoyed your detailed desription of the 'moment' the universe first became transparent. For some reason, I always struggle to visualise that concept. It usually just gets a handwavy 'and then the photons could move freely'-treatment. This was the first time I had that 'ah, now I see it!' experience about it. A lot fell into place for the first time for me.

[@frankschneider6156]

Berend Harmsen Imagine a really thick and heavy fog. You can't see very far, because the of the photons interacting with all the tiny water droplets in the air. Now imagine the same thing, but instead water droplets imagine free floating protons and electrons (which are charged so electromagnetic radiation like photons interact with them) -> same effect.