I admire the audacity of you guys even /attempting/ to explain such advanced topics and actually succeeding.

@damaliamarsi2006

5 жыл бұрын

Speak for yourself. This video cooked a pizza by giving my brain so much information it overheated trying to understand it up to the point I smelled cooking mozzarella and forgot what I was thinking about thus cooling my brain down and failing to completely cook the pizza. So all this video gave me was a half cooked pizza and a headache. That is not to say it was not fascinating and awesome and very well done. You can teach people things but you can't learn for them. I'm sure one of these days after I've heard it a few different ways I will start to understand it but for now I will just eat my cold pizza and sigh.

@psi.squared9448

5 жыл бұрын

Damalia Marsi dude stick to pewdipie

@freshhorizonswithjakub

5 жыл бұрын

@@psi.squared9448 That is just rude man.

@shahedmarleen8757

4 жыл бұрын

That's not rude!!! That's burnnnnnnnnn🤣🤣🤣🤣

@thisis4573

4 жыл бұрын

I think they make these videos to consolidate their knowledge as well as pass it on

where discovery channel makes me bored out of my skull. this channel leaves me in the fetal position rocking back and forth. best content on youtube.

@TectonicBadger

2 жыл бұрын

Thought I'd check out Brian Cox's recent BBC documentary supposedly on the physics of time. Einstein wasn't even mentioned until the last ten minutes of the hour, and the rest of it consisted mainly of Brian Cox going "Woooah timeeeeee" while looking at turtles and other unnecessary on-location segments. I won't be going to TV for science content again, Space Time is where it is at

@Andrew-zq3ip

2 жыл бұрын

@@TectonicBadger yep. Regular TV programming assumes we are stupid and that we want to stay that way. PBS Spacetime understands that we want to get better

@and_I_am_Life_the_fixer_of_all

Ай бұрын

Soft words but I can agree with the "best content on KZread" - I might add, for this time historic time period. After all, most are facts are bound by their time. Too bad they get many things wrong in this video, but I guess that is something that only those that have gone to the end of the universe would know.

The amount of stuff scientists can figure out from something like CMB is unbelievable. And how it all comes together, independently verifying each other... Congratulations on very clearly presented video!

That was one of the best explanations I've had the pleasure of listening to.

@kukulroukul4698

5 жыл бұрын

no is not

@ArakkoaChronicles

5 жыл бұрын

I think I actually understood some of the words.

@patrickt4533

5 жыл бұрын

Not that i understand most of it but your right

@mykofreder1682

5 жыл бұрын

I suspect they read some of the comments from similar videos and make a video that answers not the questions of PHDs in a complex way but people with some scientific interest in a way some can understand. It is interesting they came up with the similar results, they also did the same thing to get a universe age which matches the size of the observable universe. I wonder how the equations and constants used in these models are intertwined with the numbers generated from astronomical observations. Are things liked by the value of the expansion rate or Einstein's constant linking the results, could the real unknown expansion of space time from the beginning give us false consistency, is the relativistic frame of reference for these numbers our observable universe and not the whole unknown universe.

I will never fail to be amazed at the depth of measured and modelled evidence for the models of the universe, and frankly everything 'established' in cosmology. Anyone who doesn't appreciate the work put in by cosmologists and other professions involved in cosmology simply does not understand the multitude of information they account for. Thank you for everything, scientists and support workers.

@Mythricia1988

5 жыл бұрын

@shane I always wonder what the construction crews of these huge things think when they're working on it, so it's interesting to see that perspective. I wonder how many think of it as just another job, and how many stop and gaze at it thinking about how remarkable these machines and their results are. Either way it sounds like an amazing thing to have worked on!

@toxxikanshul

3 жыл бұрын

Cosmologist here. My core field is cmb. Thanks for appreciation anywayss 😂

I’ve watched all of these videos and when you mentioned the geometry of the universe before you explained what that meant I knew it referred to whether triangles are 180deg or not!!! It seems the primary benefit of watching SpaceTime videos is being able to understand SpaceTime videos! 🤣🤣🤣

@only1kingz

5 жыл бұрын

I love this comment haha! It's so true that I definitely understand these videos far far better now than I used to. I should re-watch the old ones now!

@Yora21

5 жыл бұрын

We are learning!

@technocore1591

5 жыл бұрын

Peter Yeah after I started watching a few that showed up randomly I decided to watch them all chronologically and now I’m thinking about going round again.

This was one of my favorite episodes ever. I'm amazed how we're able to find out so much from what seems like so little evidence.

I wish I'd've known that the Physics skill tree is required to unlock the Wizard class....

@calebmauer1751

5 жыл бұрын

Damn, I put all my points into Animal Husbandry.

@jdtug8251

5 жыл бұрын

I had a little bit in curiosity and logic prior, I invested a bit into free time and interest in physics. From that point, gathering experience into my physics tree was a breeze. I started by investing some of my time points into Neil DeGrasse Tyson, which told me how to see the world beautifully through the lens of science, and then at that point my curiosity stat exploded. I invested more into the physics tree, and I also branched into that deeper, obscure quantum tree. It's a bit difficult to master from a gameplay perspective but it teaches you to approach from a perspective of unintuitiveness that makes playing it as interesting as watching sci-fi flicks. I also branched into biology, psychology and computer science, at this point I have a lot of points invested in it, and I feel rewarded x4 every time I invest more points into the science builds. I have a sickness debuff, sadly, that keeps me from experiencing life on a "normal level" and this is my redemption. I'm hoping that one day, my skill tree investments allow me to develop new strategies against the progression bosses.

@kinhamid9665

5 жыл бұрын

Whomst'd've

@njdevilsforlifewoohoo5533

5 жыл бұрын

You don't English well. It's ok. You science even worse.

@thesuccessfulone

5 жыл бұрын

Alchemy and chemistry were parallel branches until the unifying treaty to call the entire class "master of the universe"

One thing I love about these videos is that, even where the content gets more advanced than my current knowledge, they're explained in such a way that it's possible to understand the abstract concepts. Which also then makes it much easier to fill in the gaps of my knowledge. This is a brilliant series, and a great public service. Thank you.

ah I was wondering about this!

@SwordOfApollo

5 жыл бұрын

I think it's interesting the way they use spherical harmonics in the calculations. I've always thought spherical harmonics were cool. I have a chemistry background, and I enjoyed the modeling of electron orbitals as spherically symmetric harmonics in the potential well of the nucleus. Not sure if you've done a video on spherical harmonics, but if you haven't, I think it would make an interesting topic. Maybe you could find a way to show spherical harmonics somehow. Maybe striking a hanging glass sphere filled with a colloid/gel suspension? Or playing a loud sine wave next to it?

@Vincent-kl9jy

5 жыл бұрын

yo wuddup c-dog

@aphidamas1

5 жыл бұрын

Let us all revel in awe at the great cosmic sponge!

@megsinzoa7424

5 жыл бұрын

How is your fermented urine artillery shells going m8? Sorry but i Cant be asked to check.

@SpaceCadetLaC

4 жыл бұрын

Annnd I still am.

PBS Space Time has to be the absolute best Science communicator I've seen. They don't really dumb things down in any significant measure and Matt is always careful to set the record straight to avoid falsely hyping things as the media so often does (ie. "That star over there might have an alien megastructure" one of my favorite examples of the media's clickbaiting pranks)

Man: the universe is flat Alien: And I guess you think dark energy exists too. Alien: [aside to other Alien] These flat universers, are they for real or just trolling us?

@wefuntw

4 жыл бұрын

man: show us how you measured the universe, share your tech with us! Alien friends?

@SandhillCrane42

4 жыл бұрын

Ah, the impotent absurdities of flatland. What does 3 by 3 by 3 make? Why nothing at all!

@wefuntw

4 жыл бұрын

@ZeOverman no , the observable universe is flat , does not mean whole universe is flat, it just means the curvature is not measurable within such distance. It's like when you stare distance

@cheapmovies25

4 жыл бұрын

Yeah flat earthers were on to something all along lmao

@cheapmovies25

4 жыл бұрын

@@wefuntw right imagine the weight of the universe bubble on space time under it it would be flat perhaps with a higher weight density more in the center

Wow your programs, are becoming better and better! Thank you so much! Fascinating :)

"In that noise can be found, the secrets..." oh yeah here it comes "of the earliest epochs..." wait wtf "of space time." YOU TRICKED ME

I've heard this explained a few times before but it all went over my head. This is the first time it actually makes sense lol I seriously love this channel. You guys do excellent work.

Amazing episode! I've tried to read about the CMB power spectrum a number of times and have always had my eyes glaze over. Thanks for making it approachable, you guys rock!

Wow, Matt, that was really great. And I thought the last CMB video was amazing. This was a really interesting extension love the confirmation of the relative amounts of dark matter, baryons, and dark energy.

Thanks man, you are one of my big motivations to get into astrophysics and particle physics. I'm currently at university and these videos still boggle my mind. Like "baryon-photon plasma" when I heard that I almost yelled "WHAT?!" I haven't even studied QM or relativity yet but I'm mind boggled at the idea that the speed of light is the same in all inertial reference frames. Physics KZreadr like yourself absolutely make me crave my textbooks Just to be able to understand why things do thing.

@josephlau13d77

3 жыл бұрын

recommend Susskind's theoretical minimum for an introduction to QM and SR/CfT. Maxwell equations are also a great way to start physics and is vital to electromagnetism and SR.

@nathandaniel5451

3 жыл бұрын

@@josephlau13d77 I have Griffiths introduction to quantum mechanics, as well as some more advanced texts i haven't started like Sakurai's and Shankar.

Just wanted to say thanks for providing something I look forward to and also something that actually excites me all the while explaining some of the most advanced concepts in such a simple and elegant fashion. Million thanks to you Matt for making me feel alive and also question my place in this wonderful space-time

the music you guys have had in the videos for the past couple weeks has been great. really nice touch, and subtle enough to not distract.

A tiny spot in the sky gave away the composition of the universe. What a time to be alive!

@DanFrederiksen

5 жыл бұрын

You aint seen nothing yet. When man learns to hold a thought and actually think about ball lightning, UFOs and cosmic jets things will really take off. We are so close yet so far. Like Trump telling the truth.

@kindlin

5 жыл бұрын

@@DanFrederiksen Ball lightning has some plausible explanations, and there are many other similar phenomenon that also have explanations. It just takes a tiny bit of research, a tiny, tiny bit. I don't even know what you're referring to with cosmic jets, must be some weird conspiracy theory... And UFOs? Really?

@jdtug8251

5 жыл бұрын

Well, the universe was a tiny spot. What he describes here is the minuscule shapes in that tiny spot translating to the scale of the universe as it expands, much like you still have the same traits as when you were a kid when you're an adult, but they have morphed to adapt to your growing body.

@jdtug8251

5 жыл бұрын

@@DanFrederiksen people already think about cosmic jets ? almost 100,000 saw this video, probably maximum 1% of which has the professional background to understand it without having viewed any other content on spacetime/other shows like this. I assume on those 100,000, many aren't watching their first, like me, and gradually worked their way through physics, at their own paces, with wikipedia/youtube/similar content.

@danfrederiksen1607

5 жыл бұрын

@@jdtug8251 are they? what about ball lightning? even though a stable spherical energy configuration violates known physics, try to get Matt here to take it seriously. Try to get yourself to take it seriously. When something is implied in our society to be taboo, very few can think about it. Most will shy, irrespective of apparent intelligence. Scared in a sense, it blocks their mind completely. Forcing the issue will only make them angry and blame you.

I always feel sad when I hear "of space time" because that means the end of the video :'(

We truly are blessed to have channels like this.

Being a big fan from this channel for years, i just discovered this amazing video today (12/2020) almost two years after it was pubished. So much good and well thought out content content, BEST KZread CHANNEL EVER !!

Finally. A Space time I can understand

@whoisthis4948

3 жыл бұрын

Other than Palkia and Dialga? lol

@Zeegoku1007

3 жыл бұрын

@@whoisthis4948 What ?

@whoisthis4948

3 жыл бұрын

@@Zeegoku1007 oh damn I forgot about this comment XD

@whoisthis4948

3 жыл бұрын

@@Zeegoku1007 Verlisify is a pokemon youtuber and palkia and dialga are the space and time pokemon

@Zeegoku1007

3 жыл бұрын

@@whoisthis4948 Ah I see 😁

I always wanted a video on this, great content!

@drew8443

5 жыл бұрын

Good luck with your future physicist career!

@sahilbaori9052

5 жыл бұрын

Is that complex or a compound sentence?

@TheCimbrianBull

5 жыл бұрын

Y'er a wizard, Juki! 🧙🏿‍♂️

You guys have amazing content. I'm back in college and as I make my way through my math classes I gain just a little more insight to your videos. Keep up the good work!

Sometimes I feel like I'm keeping up with you and I'm like "yes OMG, go on.."and then I get distracted for a spit second and I've lost it. I love this channel, and I love even half understanding what you say half the time. Don't ever leave :)

Wouldn't the "moment" of recombination depend upon the local density? I would expect high-density regions to reach recombination a little later than low-density regions. It also seems like the speed of sound would be density-dependent.

@cjfontaine9206

5 жыл бұрын

He does mention at 6:22 that the "speed of sound" in baryon-photon plasma is half the speed of light, which is way faster than it is on Earth.

@AbeDillon

5 жыл бұрын

@@cjfontaine9206 Yes, I saw that. I'm still curious if the speed of sound was uniform and if not, how much it vary.

@AbeDillon

5 жыл бұрын

@@jacobpilawa203 Thanks for the reply. I think the more relevant measure is how long after the Big Bang the moment of recombination happened. He says (~ 0:59) that the CMB formed 380,000 years after the Big Bang in which case +/- 1000 years is a more significant number. Though I'm curious what the actual time-scales were.

@user-vc5zt9ci12

5 жыл бұрын

I think it may be due to the vast majority of the energy being bound up in the photons, which were more homogeneous, rather than the baryons. However, I still think it is a valid point which deserves a shout in next weeks review!

@mal2ksc

5 жыл бұрын

Yes, the moment of recombination was different from place to place. The question is if that would leave enough of a trace to be discernible now. If not, there's no sense worrying about it.

"You Will Be A Wizard" - way to roast somebody...

@SimWyatt

5 жыл бұрын

Do you think he knows what he said there?? ^^

@yaldabaoth2

5 жыл бұрын

Still better than a bard.

@chrisgeorgakopoulos7519

5 жыл бұрын

Well, depending on the definition of "done", you very well may be a wizard.

@RyanSandorRichards

5 жыл бұрын

Man, I loved that little quip at the end XD

@sahilbaori9052

5 жыл бұрын

@@SimWyatt Uhhhhhh Yes?

Of all the videos that he does this is by far my most favorite one it's something I you can relate to as a kid when you look at the static on the TV and wonder where does that come from.

How this was even put into a coherent presentation is mind blowing which doesn't even scratch the surface on the science that went into figuring all this out. I am humbled.

Im in love with these radiation videos lel

Oh.... Oh, 'oscillation stacking'... No wonder my calculations are so off the mark! * puts down the ocelots and frowns at the chalkboard *

@fuckoffannoyingutube

5 жыл бұрын

wait. you're here as well? it's always good to run into you :) you're one of my favourite internet strangers

@tiresias3342

5 жыл бұрын

New Message this isn't comedy

@tabaks

5 жыл бұрын

Tiresias, he isn't smart enough.

@tiresias3342

5 жыл бұрын

tabaks what

@account1307

5 жыл бұрын

Hkllhihlilhi

My mind is blown. Thank you. I don’t have enough time for these topics, so your videos are a real treat!

This vid is amazing. You always dive into the kind of stuff that’s on the edge of my knowledge but it’s infatuating

The combination of oscillations of many sizes... sounds like Fourier Analysis

@SolarShado

5 жыл бұрын

I thought that too! Was kinda hoping he'd mention it so I could be sure.

@gm683

5 жыл бұрын

Was about to comment the same

@TheRealFlenuan

5 жыл бұрын

Well it literally is the reverse. Fourier analysis is what is used to rewind the clock

5 жыл бұрын

@@TheRealFlenuan ... and your background is? I feel pretty confident that Fourier Analysis is waveform analysis, and these are spherical waves they are looking for.

@TheWasimu

5 жыл бұрын

It is very similar to Fourier analysis. With Fourier analysys you decompose your signal with trigonometric (sine, cosine) functions. This is good on a flat space (line, flat plane,...) but since in the present case you want to do the analysis on the surface of a sphere you decompose your signal in functions called spherical harmonics.

But can I use the CMB to microwave my leftover pizza?

@danielkirk4755

5 жыл бұрын

Only if you like your leftovers at 2.7 Kelvin :p

@crackedemerald4930

5 жыл бұрын

But what if i use a big lens- No... It would be 2.7 Kelvin... Only faster

@bastawa

5 жыл бұрын

Sorry I have already used it and that’s why it is only 2,7 kelvins

@kennyhoughton

5 жыл бұрын

Call me ‘Kennedy G’ but I was wondering if this uses the scaling term at all (1- 2c^2/aΘ) In the tensor calculus for the early universe?

@DANGJOS

5 жыл бұрын

@@crackedemerald4930 Magnifying microwaves on pizza wouldn't cool it.

Well that was super understandable and informative. Best video in a while, I love it! Thank you so much for these. It's amazing we have these useful, informative channels.

This is such an insane channel. Thanks for blowing my mind each time.

Great video! Is it me or they are using a new microphone? It sounds really good.

@mahditr5023

5 жыл бұрын

Ikr

@aygwm

5 жыл бұрын

I think they’re using more compression.

@BenoHourglass

5 жыл бұрын

They changed volume with the answers segment.

@brandonboilard1956

5 жыл бұрын

I can hear every breath he takes its making me go crazy

nice

always love these videos!! Amazing, i have always wanted to know how to understand the CMB, thanks for this, very interesting :)

Awesome episode! Will definitely be watching multiple times in order to get my head around all of it!

Thank you for explaining physics in clear English. What do you think of Quantized Inertia vs Dark matter?

@inertia186

5 жыл бұрын

I'm curious about the notion of quantized inertia as well. Specifically, how does QI hold up to this presumed verification of a Dark Matter / Dark Energy audit that the CMB appears to reveal here in this video? In other words, does Dark Matter / Dark Energy explain this CMB data better than QI does, if at all?

@gabor6259

5 жыл бұрын

Someone commented that the theory of QI ignores the things that contradict it and it can't be true, though it's very elegant.

im a biologist, this is like the "omics" approach being applied in physics (to great results!)

This was your best video yet. Truly great inference from minimal information. Very well presented. Thanks

That project must win a contest for the most important information taken by one series of observations. And the most amazing.

This explains wandavision

How's the cosmic neutrino background coming? That's very exciting

@nafrost2787

5 жыл бұрын

Wow they should totally do a video about it. I’ve heard something like those early neutrinos are lighter than current ones. Do you know anything about it?

@leeparker5822

5 жыл бұрын

@@nafrost2787 I've seen a few videos .. I think we're a bit away from finishing it but sounds like we could look back to seconds after BB not years with sooo much more information. I hope he does a video it's very exciting

@nafrost2787

5 жыл бұрын

Yeah that’s the idea that because neutrinos hardly interact with matter, they could have decoupled from matter much earlier. But also I have heard something like that those early neutrinos would have been much lighter than neutrinos today. Do you know anything about it?

@leeparker5822

5 жыл бұрын

@@nafrost2787 lol no I'm just a carpenter from London done qft qed 101 tho

@nafrost2787

5 жыл бұрын

Nice, the fact that you’re interested in science is good enough. I’m 17 years old, and I want to do something with science in my future, my direction is the theory of everything.

i have spent the last 2 days trying to understand this for my midterm tomorrow and this is the only helpful explanation i have found online. Thank you i feel so enlightened

@seanj3667

Жыл бұрын

How did you do?

@emiliavlahos3956

Жыл бұрын

@@seanj3667 pretty good tbh

17:04 he still have whole 17 years to rethink his career choice.

@tuele4302

5 жыл бұрын

Or be able to realize his dream.

@AlexanderLouizosLouizos

5 жыл бұрын

@@tuele4302 its all about dreams

@Noman1000

5 жыл бұрын

:^)

@tuele4302

5 жыл бұрын

@Alexander Louizos Louizos Sometimes, dreams can come true.

@DvDick

5 жыл бұрын

It's hard but definitely rewarding if you're into it

Those early Rings. Sauron was there.

Finally I got to understand that power spectrum :-). Great episode again, thank you!

Damn! This is an insanely awesome result! Secrets of cosmic history springing (heh) forth from stats and geometry! Cheers for the episode 😁

If the universe is currently geometrically flat but still expanding due to dark energy, does that mean in deep time (post the baryonic / dark matter era after all particles have broken down) there will eventually be enough curvature introduced purely from dark energy to cause it to folk in on itself?

@only1kingz

5 жыл бұрын

Since dark energy is constant regardless of expansion, I think it will remain flat. I think..

@kazedcat

5 жыл бұрын

@@only1kingz But the universe is flat because of the total energy. As all baryon, dark matter and photons gets diluted the total energy will be less than the required number to remain flat.

@carloguerrero6583

5 жыл бұрын

Dark energy acts as our expansive force. Since as far as we know it doesn´t dilute, it leads to an ever expanding universe. This is the accepted theory on the end of the universe. I´m not sure about the curvature tho, i think that IF it changes, it´s going to go towards negative curvature, so the oposite of collapsing inwards

@cholten99

5 жыл бұрын

I've been thinking about this and actually it was a pretty dumb question :-). If mass-having particles have radiated away and all that is left is dark-energy filled space then each cubic meter of that will have exactly the same energy and therefore space will be *very* flat.

@jaydienparks5658

5 жыл бұрын

@pyropulse we don't actually know that it could change with time

My brain feels better when I'm here.

This is the best explanation I've heard about. Just the right amount of information.

Thank you so much for making these videos! No doubt makes for the best 15 mins of the week

I'm asking this question again. How do astronomers distinguish the very small temperature differences in the CMB from the microwave noise of all the stuff the CMB has to shine through to reach their instruments?

@Crootcovitz

5 жыл бұрын

With precise measurements and a lot of Maths. I remember reading about it a long time ago, but that's all I can recall.

@cherrydragon3120

5 жыл бұрын

Most of it is an estimation. They can't 100% proof it because of it. They may say its a fact. But most of this type of science is estimations combined to math. If the answer is close enough to their estimation they say it has to be a fact.

@TheRealFlenuan

5 жыл бұрын

By taking the measurements in multiple locations. The CMB in theory should measure the same wherever you are on Earth, but the noise originating from Earth should vary. All you have to do is use some math involving Fourier transforms to figure out the information that the signals share. Essentially the same process is used to read gravitational waves too.

@harryscrotum007

5 жыл бұрын

They can't actually measure anything unless they right there to measure it. Most of astronomy and space science is make beleive. It could be real but nobody actually directly measured it therefore an idea make beleive.

@boyan3001

5 жыл бұрын

Basically it's same principle as microphone noise cancellation. With one or more microphone you are catichng ambient noise and when you have clear picture how that signal should look like, you can subtract it from signal that is captured by primary microphone.

Question - I'm more of a layman than most in this comment section, having never studied any science but actively following this channel, so this might be a dumb question, but: could we literally spot on an image of a lot of galaxies these circular ring patterns, and if so, where can I watch that picture?

@AlemitoFilms

5 жыл бұрын

BelgianGeneral good question, actually I’d like to know too. Maybe the circular pattern is so faint in the apparent random disposition of the galaxies that only a computer algorithm can detect it. But if someone can link an eye visible example I’d be very interested

@psykkomancz

5 жыл бұрын

Theoretically, yes. I did some math, and considering how big those rings are , it would be possible to see them at the distance around 500 milions of light years withnin a 10 degree span of sky. The true problem is that there are so many objects until that distance that to capture photo where those rings would be clearly visible is practically impossible.

@TheHellogs4444

5 жыл бұрын

Didn't PBS show such a real-life-image picture in the last episode?

@danshultz11588

5 жыл бұрын

Watch the video that came out before this one on this channel and he goes over it. It's not nearly as complicated as this one was.

@danshultz11588

5 жыл бұрын

kzread.info/dash/bejne/goSkt9qoldLVis4.html

Matt you are great. I enjoy this non-dumbed down scientific divulgation immensely: the audacity of what scientists do is inspiring, and the conclusions are breathtaking. When I was little and watched Cosmos on TV I was equally fascinated by Carl Sagan's voice and presence and the message he conveyed. It's beautiful that Cosmos, as his wife says in the anniversary edition, needs little revision. Since then, I have read lots of divulgation but only the Feynman lectures have fascinated me so much, with his approach of explaining QM how we know it but without the mathematical machinery. I'm glad to be able to say that you continue on that tradition of accurate divulgation, obviating the maths. Your work is wonderful.

This is amazing but even more fascinating is the explanation of the topic.

Q.does elecrtomagnatic field affect space time?

@Yora21

5 жыл бұрын

It is part of it.

@ferdinandkraft857

5 жыл бұрын

Yes, the electromagnetic field contributes to the stress-energy tensor, which is the source of spacetime curvature: en.m.wikipedia.org/wiki/Stress%E2%80%93energy_tensor

Magic is real, but we call it science.

@jojolafrite90

5 жыл бұрын

It always was a matter of perspective.

@Aurinkohirvi

5 жыл бұрын

I would appreciate if they worre the pointy hat and wielded a wand though.

@calebmauer1751

5 жыл бұрын

"Any sufficiently advanced technology is indistinguishable from magic." -Arthur C Clarke

@kazedcat

5 жыл бұрын

@@calebmauer1751 Yeah but what do you call a sufficiently advance magic?

@jdtug8251

5 жыл бұрын

...and Science makes better stories than science-fiction. =)

This is amazing! 😍 I love everything related to space, so this explanation is truly perfect! Thanks!

Big thumbs up for the fun-yet-inspiring pep talk at the end. Nice one Dr. O'Dowd.

I’m a new subscriber

Lays in bed a hears static: I guess I'm studying history tonight

The best video on the CMB power spectrum in KZread period.

i’m totally down with the collared shirt. you’re making physics look fresh

So Chuck Norris used a microwave once,so what?)

I love you, Matt, but you don't have to try do hard on your Rs when you talk. Your accent is wonderful on its own.

This is fantastic. Great job explaining.

Amazing, eye opening video and incredibly well explained

Since the universe is expanding, will it eventually gain negative curvature?

@bossninja0612

5 жыл бұрын

No. As far as we can tell our universe is geometrically flat. It's flat because the total energy we can measure is equal to 0.

@kazedcat

5 жыл бұрын

@@bossninja0612 But dark energy is constantly being created. As the universe expand the new empty space created will have dark energy which makes the universe expand faster creating more empty space that have more dark energy. That is a positive feedback loop that creates more and more dark energy.

@bossninja0612

5 жыл бұрын

Lol I'm sorry to say but it doesn't seem like you know what you're talking about. All the energy that ever will be was dispersed during the big bang. You can't create nor destroy energy. The universe is simply expanding into itself.

@ytpanda398

5 жыл бұрын

@@bossninja0612 sorry this kinda messes with my brain a bit bear with me. Is it rate of expansion proportional to total energy? As far as I understand isn't the rate of expansion increasing? Thanks for your help

@mal2ksc

5 жыл бұрын

physics.stackexchange.com/questions/33404/how-is-dark-energy-consistent-with-conservation-of-mass-and-energy

Why is the CMB shown as an oval ?

@cherrydragon3120

5 жыл бұрын

Flat mapping. Flat mapping the earth is also oval like. Even tho its a sphere. But yeah... if the Universe is flat... then whats the point of an oval... unless the universe is actualy flat and rounded up as a cilinder... or actual spherical

@YYYValentine

5 жыл бұрын

It one type of projection which project a sphere (sky) into 2D. You can find something similar earth maps.

@TheRealFlenuan

5 жыл бұрын

Imagine a sphere surface made of infinite circles of latitude. When you project a sphere onto two dimensions, one way to do it is to take each of these circles and unwind it into a line. The resulting shape is an ellipse whose height is the height of the sphere (2 radii) but whose width is the circumference (2π radii), and so you get that shape. It's called the Mollweide projection.

@MrAlRats

5 жыл бұрын

It's a map of the whole sky. Check out this article. en.wikipedia.org/wiki/Mollweide_projection

@YYYValentine

5 жыл бұрын

@@cherrydragon3120 Flat universe with a spherical "boundary". (It is not a real boundary, it is a boundary of time.

Great tutorial on the CMB! Our lab at UCSD is on the forefront of experimental cosmology on the CMB and collaborating on building the Simons Observatory. Polarization matters!

Finally I understand how geometry was used to measure the flatness of the universe. Thank you! Other videos I watched just drew a big sharp triangle on the image of the CMB and that never made any sense to me.

[Contains Question] You say it jokingly, but it has been my belief, since I was a small child, that Science *IS* Magic. It's the only form of Magic which actually worked! We tried so many forms, and we *did* find the 'One True Magic'. We then went on to miscatagorize all the ones which *didn't* work as 'Magic,' though Science more fits the definition. Mighty Google defines Magic as, *"The power of apparently influencing the course of events by using mysterious or supernatural forces."* 'Supernatural' is a non-sequitur, as 'Nature' is really a synonym for "The whole Universe, excluding stuff we make, but not really." So we'll replace 'Supernatural' with 'Natural'. Mystery is merely a matter of perspective, as something can be Mysterious to the uninformed, but old-hat to the expert. We'll replace 'Mysterious' with 'Understandable.' Our definition is now, *"The power of apparently influencing the course of events by using understandable natural forces."* So, Yes, you *ARE* a Wizard, though I've often thought of Physicists as 'Sorcerers.' You work more directly with the Primal Forces. Engineers are Wizards, and we make Golems and Enchanted Tools, Weapons and Armor! ;P [*Question Begins here*] Now, with all that said, I have a question to be of the Grand Sorcerer Supreme: It has to do with Black Holes, I'm afraid... It seems to me, in all the explanations I've ever heard, that crossing the Event Horizon of a black hole is actually on the Table as a reasonable question, but it only makes sense, to me, if you don't factor in Time Dilation, especially as we now understand that black holes evaporate. Imagine that we had a probe with a magical warp shield. It is immune from outside gravity wells, though it can still experience time dilation due to being in one. Again, it's magic. Doesn't matter how it works, all we want to do is track a single 'camera' inside the black hole's region of affected space-time. Now we line the probe up with the middle of the singularity and give it a nudge. As it falls in to the gravity well, it'll experience time-dilation, relative to the outside universe. It'll see stuff 'out-there' speeding up and we'll see _it_ slowing down. But the part that never seems to be discussed is, "What does the probe see the Black Hole doing, time-dilation-wise?" Well, we know that the Event Horizon is shrinking, via Hawking's radiation, if ever so slowly from our point of view. However, the probe is now much closer to the Black Hole, so it's deeper in the gravity well, so it's clock is running at a speed more comparable to the one in the Singularity, so the Black Hole appears to speed up, to the probe. We see the Event Horizon shrinking more quickly, pulling away from our probe. Let's speed up our probe. As we do, we see the Event Horizon slip away even faster, because we're falling deeper and deeper into the gravity well and our internal clock is slowing down so much that even the glacial timelines of a Black Hole seem fast. We'd never be able to cross the Event Horizon, because accelerating (or even drifting) toward it would cause it to zoom away, until it was a tiny as the matter inside could be compressed to be (whatever the minimum 'packing distance' of 'stuff' is in our Universe) then it would explode as a GRB. But our probe would be billions and billions of years in the future. If our probe could hover just beyond the Event Horizon at the instant of a Black Hole's creation, and 'follow' the Horizon in, the probe wouldn't even notice a 'Black Hole' at all, or only for an instant; the length of time it takes the Horizon to sweep the space from the edge of the Schwarzschild radius to the edge of the 'Sphere of Minimal Packing,' at [C-(distance from Horizon)] or nearly the speed of light. Ergo: Black Holes both Exist and Don't exist, depending on how close you are to them?!?

@iestynne

5 жыл бұрын

Corbald very interesting thought experiment! So you suggest that nothing can enter a black hole because doing so requires traveling further into the future than the actual lifespan of the black hole. How would this account for matter that is already inside the event horizon at the moment that the event horizon forms? Is there a great schism at this moment, a bifurcation of permanently diverging timelines - matter inside and matter outside, never the twain shall meet? And what would be the "experience" of matter just slightly inside the horizon?

@Corbald

5 жыл бұрын

@@iestynne For the first part, yes! I couldn't (apparently) have said it better! For the second part, no, I think the matter inside the shrinking event horizon is converted to gamma radiation once it has shrunk past the point where degenerate matter can hold up. Actually, the length of time it takes (in it's own time frame) to explode is the speed of matter in the center of the degenerate matter 'ball' converting to gamma radiation, then forcing it's way through further collapsing matter as that is converted, center out. Like how light has to force it's way through the Sun to escape. Or something to that effect, I think.

@ferdinandkraft857

5 жыл бұрын

It's an interesting thought experiment, but please note that Hawking radiation is a prediction of QFT in curved Spacetime, so it's not part of general relativity. It would be a very interesting calculation if you'd compare the rate of evaporation and the time to cross the (shrinking) horizon from the perspective of a falling observer.

@carloguerrero6583

5 жыл бұрын

Jeesh. That intro was good, changing words like that raises eyebrows tho. Very nice thought experiment and well explained to boot. noice. Though it does raise some issues this seems to be calculable. If the ratios line up just right, the in-falling matter (including you probe) could still contribute to the mass of the black hole by just being close to it while being invisible to outside beings by being MASSIVELY red-shifted by the black hole. The mechanics of this warp stuff just go over my head at the moment though. AND (this just occured to me, i saw it on a PBS NOVA episode with Brian Greene some years ago) i´ve heard that as not massless objects aproach lightspeed they ¨flatten up¨ along their c-aproaching vector while the world around them flattening up in the same way from their perspective. Sooooooo look at this. kzread.info/dash/bejne/q4uDj8Wvd6i6grQ.html Very interesting don´t ´cha think? A test could be a probe aproaching as big a black hole as possible, as slow as possible with the biggest ultra low frequency radio antenna we can hang on it.

@garethdean6382

5 жыл бұрын

A good question and one that can be tricky to figure out. The first issue is that you're assuming that the black hole is going to be 'sped up' as the probe's own time slows down. This is not true because the black hole itself is deeper into its own gravity well than the probe is. From an infinite distance away a probe at the horizon would appear frozen, infinitely slowed, while things further out appear less so. From those further probes then wed expect to see things further from the hole sped up, but things closer to the hole still slowed. The hole itself we would expect to remain frozen (Infinity divided by any number is still infinity.) What about hawking radiation? Well this is an effect of the space AROUND the black hole to a radius of about twice the hole's own radius. (The reasons for this are explained in another PBS video.) This is why Hawking radiation is possible at all instead of being infinitely time dilated to a standstill as it would be if it had to emerge directly from the hole itself. Now there ARE speeding effects due to the probe's speed. Imagine a probe going before, shooting photons out behind it at regular intervals. Now our second probe is going to be following the first and moving directly towards those photons, blueshifting them. So the second probe will see the first 'sped up' compared to a stationary distant observer. But the speedup can't be infinite or the second probe would catch up to and\or pass the first at some point. In fact the speedup is quite mild all things considered. So for any black hole heavier than about the state of Texas it's possible to fall into it before it evaporates. Interestingly enough the 'Outsiders can't see anything fall into the hole' scenario is actually only true in one very, very special case and most 'real' observers most certainly will see stuff fall into a hole.

After you are done with the CMB, do an episode on quantum loop gravity

Just when I think I know what's going on in the universe, PBS ST blows my mind again.

Mind: Blown. Thanks again PBS Space Time!

A whole video about me! 🙃

Here before the background radiation was.

@FunScientifix

5 жыл бұрын

Here Officer. This comment right here

@KanwardeepSinghNarota

5 жыл бұрын

Microwave radiation 4 m she’s only I love more then myself

@tatjanagobold2810

5 жыл бұрын

Are you a primordial gravitational wave?

@wythaaof6650

5 жыл бұрын

lol best "first" comment ever

@KanwardeepSinghNarota

5 жыл бұрын

t. gobold yes guid me to success

It never ceases to amaze me how much can be derived from the CMB.

I've watched 10^3s presentations - this is the first time I've wished that I could give more than one "like". In fact, this deserves 5. Beautiful! Thanks for the goosebumps.

But can it heat my hot pockets properly?

@matthewtalbot6505

5 жыл бұрын

No, quantum mechanics forbids this

I suspect 'dark matter' is a theological idea - we can 'explain' what we see but are only at a ptolemaic understanding, equivalent to epicycles and deferents.

@WanDeLay4

5 жыл бұрын

Forgive me if I'm wrong, but did you just use the "I don't know, therefore it's God" argument? Historically speaking, that argument is a bad bet.

@dinf8940

5 жыл бұрын

'suspect' hehe, when mainstream astronomy fails to make single valid prediction for nigh 100yrs, is constantly stumped witch each new observation yet keeps adding layers of complexity to prop up their obviously faulty models, id say its safe to say we are way past suspecting at this point

@kazedcat

5 жыл бұрын

Did you not watch the video. You need mass that does not react with photons to provide a braking effect on normal matter oscillation. This mass must be independent of ordinary matter otherwise they will bounce with them and not provide the needed braking effect. We can measure how much mass that does not bounce based on the peaks of bouncing mass. This non bouncing mass is dark matter because ordinary matter bounce. That is Baryonic Acoustic Oscillation.

@DavidMaurand

5 жыл бұрын

WanDeLay4 the opposite.. the presenter promoted dark matter as an established fact, rather than issuing the caveat 'the math indicates there is far more matter than we can detect, we don't have a clue as to what it is...or whether our math is wrong." For centuries, the math worked for ptolemaic astronomy, until Copernicus recalculated the same numbers. Confirmation bias is a powerful force.

@garethdean6382

5 жыл бұрын

Dark matter IS a fact. Stars in galaxies orbit far faster than visible matter allows. WHAT dark matter is is unknown but it's definitely there. And 'the math is wrong' has been tried. Modified Newtonian Dynamics was the first attempt, tweaking the math of gravity. The problem with it and other 'wrong math' theories is that they're too simple. Some galaxies are >99% dark matter some have none at all. Large galaxies have a mostly consistent amount, dwarf ones vary. Changing math fixed ALL the orbits of our solar system's planets. Changing math with ark matter can fix only a handful of galaxies. This HEAVILY suggests dark matter is a THING which you can get varying amounts of. Ironically attempting to make wrong math theories fit its observations itself tends to add epicycles. 'There's some stuff out there we can't see' is a pretty simple model. When the orbits of the gas giants seemed a little off it didn't mean that Copernicus was wrong, it meant there were some undiscovered planets out there. Once again we face some odd orbits that seem immune to mathematical tinkering. Soemthing's out there and people are desperately trying to pin down what.

PBS Space Time is the best

One of the best videos on this channel

1 down vote... It's been up for 4mins. Does this person like to be uninformed?

@CloudsGirl7

5 жыл бұрын

They probably believe there's a sauropod living in the Congo.

@trewq398

5 жыл бұрын

yeah why did he do that

@Melthornal

5 жыл бұрын

youtube (and all social networks) display semi random numbers of up and downvotes in addition to real votes. this os partially because its borderline impossible to measure the number of actual votes and also because they want to prevent people from gaming the system to get their content promoted.

@GeorgeD559

5 жыл бұрын

fuck them assholes.

@UATU.

5 жыл бұрын

Let them relish their illusion of power, it keeps them off the streets

Thank you, thank you, thank you! What an amazing and clear explanation.

This is one of your best explained videos IMHO

Nothing makes me happier than coming to this channel!!!

Fantastic program. I've seen the power spectrum graph before but did not understand what it meant. Amazing how much information scientists are able to tease out of the CMB. That this analysis agrees with other estimates is awesome. It indicates our understanding of physics is on the right track. Considering we have barely left our little planet and our brains evolved to keep from getting eaten by tigers being able to figure this stuff out is a testament to our capabilities.

Wow!! That's amazing. Thanks for showing us the whole reasoning process :P

Best episode of Space Time right here.

This was very palatable, and I found that it tied some seemingly arbitrary information together into a nice package. Kudos

Good follow up to last video. This is what the public needs, good explanation of how data from the last video can now prove the universe is geometrically flat. I always wondered how Astronomers were so sure of these results, but after this video it's apparent. Thank you.