The Crisis in Cosmology

[@vellyxenya3970]

"Dark Energy = Dark matter * (Speed of Dark)^2" got me laughing for much longer than I should have

[@traviskelsey6674]

His delivery was beautiful. I had to rewind the video (a T-reversal, if you will) to properly appreciate it.

[@ChronoSquare]

Given that the speed of dark exceeds (can exceed) the speed of light... it's a scary thought!

[@Semicon07]

That's because you are a human...and all humans find bullshit amusing.

[@forthebirds4]

DE=DM(can'tc)^2

[@easyeagle2]

And now, Dark Flow. I am laughing too long too. Lololol. Cosmology is getting humorous.

[@RR-fi4oh]

Whether you use standard candles or cosmic microwave, your frozen burrito is still going to have a great cold spot.

[@deathbydeviceable]

If you add the size of the burrito vs time nuked, fixed with trial and error, that cold spot will be non existent in about ten burritos

[@xCorvus7x]

@@deathbydeviceable I beg your pardon?

[@PainterVierax]

is burrito the new time measurement in the USA ?

[@RR-fi4oh]

@@PainterVierax We are not quite there yet. Give us a few more decades of demographic blueshift.

[@PainterVierax]

Maybe the future president will be the Taco Bell CEO

[@Eilen15]

I love to imagine what PBS Space Time will talk about 20 years from now, seeing how much questions about space time still haven’t been answered ^^

[@CornerCaseStudio]

The only thing I'm sure about is that we'll still be arguing with Flat Earthers in the comment section.

[@eggsngritstn]

They will be be advanced enough at space time to eliminate the questions from the start.

[@johnk4437]

A decent treatment of this outstanding problem in current cosmology... not too overly detailed, clear, and thorough ! Great job !

[@artbyjes]

I get soooooo excited when there’s an argument between prediction and observation at this level - because it means we are missing something. And that means more science! MORE SCIENCE! 😁👍

[@robknight9406]

perhaps it's something like the idea that the atoms in our universe are also expanding proportional to their size, throwing off the results. i like the expansion of atoms idea as it can also explain gravity!

[@life42theuniverse]

Even more excited when it is discrepancy between two observations?

[@adventureseeker8988]

Look into Thunderbolts projects channel.

[@chrisdonovan1642]

Jes Ewers the experts are always shocked at what we find...They have no idea. Observations are nearly always far off from their predictions. They really dont know

[@dedskin1]

Science = Physics =Math you dont want more Math nor do you need it . What you need is Metaphysics= Reasons and explanation why something is . As soon as you ask Why? You are on a good Because Why implies that there is some grand design , and everything has a reason why it is what it is . There is not a single thing in the nature that doesnt have a WHY But common ppl that enjoy science dont have one Answer to any of it . They are not even used to that question. If i Ask Why Gravity , not what is Gravity? What can a scientist say , lies are done , and they dont have the truth , so they wont even answer it . On the other hand Metaphysics can answer that question truthfully. And iknow that becasue i am in to Methaphisics , not Physics or math . But philosophy behind it .

[@ahmedabbas4434]

*An engineer walks in* Just take the average of the results and call it a day...

[@dasaggropop1244]

it's easier on the computer, too.

[@brawnstein]

sin(x)=x

[@TheArnoldification]

stop bullying me :(

[@xarmanhskafragos2516]

I laughted way too much to that.

[@coopergates9680]

@@brawnstein Sqrt(x^2) = x

[@antoineroquentin2297]

we could just cut the photons in half and count the rings

[@killssingasuka7819]

No. Photons are not discrete. They are destroyed by further knowledge... but you knew that.

[@yeeterchungus3887]

***that's not how that works***

[@adizmal]

Yes it is, Yeeter.

[@domu]

@@yeeterchungus3887 woosh

[@isaakloewen5172]

That’s not how mafia works

[@MCsCreations]

That's great. It may means that we are wrong about something and need to rethink things. And that's a great opportunity for us to discover what is wrong, but also to consolidate what's right.

[@justinfarnell2284]

You are right. Mainstream cosmology is a house of cards built on wrong assumptions.

[@MCsCreations]

@@justinfarnell2284 That's not exactly what I meant...

[@thesavantart8480]

@@justinfarnell2284 he was right, you are wrong.

[@dr.ambiguous4913]

Justin Farnell That’s a bit of an ignorant statement.

[@TheMarrethiel]

My 8 yo son wants to be an astro-physicist, this gives me hope that the universe won't be explained by the time he finishes school :)

[@firestem4]

Thank you PBS and Matt! This is one of the most enjoyable and informative shows on youtube and anywhere else. I'm fascinated by astrophysics and these episodes only help to raise my interest until I can start taking these courses for my degree.

[@TheBendejo]

"We know everything, as long as we can prove this number is constant" "... damnit."

[@raymondpopple6390]

😂😂😂

[@Myvoetisseer]

Man I'm smart. *watches PBS video* Man I'm stupid.

[@chaost11]

The way I see it, being smart is knowing how little you really know. I think that's a famous quote too, actually, but I don't remember who said it :p

[@jozsefkalmar7054]

@@chaost11 Me neither, but (s)he must have been wisest of all the Geeks. Or so it would seem :)

[@brucewayne9985]

@@chaost11 I think you're referring to Socrates "I know that I know nothing" to a certain extent.

[@iainpattison903]

@@chaost11 Plato.

[@PifflePrattle]

Man I'm dumb. Watch flat earth video - Hello Stockholm

[@slother93]

The Hubble . . . variable?

[@ZeHoSmusician]

That's what I thought! Plot twist!

[@donaldendsley6199]

That's what I'm wondering. The CMB clearly shows different energy levels throughout the universe, so why would the rate of expansion be the same throughout the universe?

[@JavierCarron]

@@donaldendsley6199 Good question! It is not, the Hubble parameter varies with the expansion of the Universe. But we have a very good understanding of how it varies, so obtaining the value at the "time of the CMB" means knowing the value in the current time. The Hubble constant is just the value of the Hubble parameter now.

[@drx1xym154]

@@donaldendsley6199 -- yes the variance, so far, is very slight - AFAIK. . The bigger question is why we have any variance or even the measured variance.

[@stevejordan7275]

I believe you have my stapler.

[@josephcampbell4724]

Socrates: Shall we set down astronomy among the objects of study? Glaucon: I think so, to know something about the seasons, the months and the years is of use for military purposes, as well as for agriculture and for navigation. Socrates: It amuses me to see how afraid you are, lest the common herd of people should accuse you of recommending useless studies. - Socrates

[@harleyspeedthrust4013]

Is that from his Apology? It's been a while but I remember seeing the name Glaucon

[@martir.7653]

7:41 subtitles say "are a factor of 100,000 cooler", but actually 1/100,000. A mere 10 orders of magnitude wrong :)

[@FlamingAtheist]

I need to get the BGM for these episodes. They are so calming and great to listen to while having a learn

[@Dzeroed]

Well the answer is obvious isn't it? Hubble Constant = 42

[@papaclanc]

Yawn. . .

[@BRUTALLEGENDD]

Yes the answer to the question is indeed 42. I will let my depressed AI robot, Marvin, to explain why the answer is 42 and why we do not know what the question is. Maybe it is a quantum thing.

[@laur-unstagenameactuallyca1587]

@@BRUTALLEGENDD "why we do not know what the question is" stop 😂

[@DG123z]

@@BRUTALLEGENDD At what age does a person truly realize their life has been completely pointless and that there is no meaning in the universe.

[@georgeb.wolffsohn30]

@@DG123z the universe is it's own meaning.

[@LeeGoGators]

I think it's fair to say the calculation based off the CMBR relies on more assumptions than that of Type 1a Supernovae.

[@soheil527]

there are several stars going supernova over and over again which the scientists cannot explain

[@oliver_siegel]

Agreed

[@BryanM61]

@@soheil527 Yes, the scientists can explain it. It's only one supernova, but 'gravitational lensing' from galaxies in between us and the supernova give the appearance that the supernova exists at a) different places at the same time, and b) at different times. In other words, we'll see the same single supernova perhaps several different times, in some cases years apart.

[@mememem]

Not so constant now, eh?

[@Skeleton-bs7zy]

meme What rule 34 are you

[@sakari_n]

i did not expect to see u here

[@arcaneinane]

Love the profile picture

[@05TE]

I've noticed that if you want to discover new physics it's a good idea to take a closer look at constants. A lot of them have turned out to be "constant" in special cases only.

[@InfinnacageMusic]

Cirno.

[@Maximus_Novin]

What I love most about these shows is that it allows for understanding to be both mathematical and hypothetical! Allowing for the furtherment of... Spacetime...

[@bostonmetalclips]

I love when you say things are easy.

[@michaelsommers2356]

I really do wish you'd include links to the papers you cite.

[@michaelsommers2356]

@Sammy Smith I meant specifically the most recent papers.

[@isaachess9356]

@@michaelsommers2356 a list of a few related papers would be nice

[@carterredfearn4249]

Why did this get taken down for like 30 minutes? I was watching and it was just deleted from existence. Am I a time Traveller?

[@JeremyKolassa]

You were in fact quantum tunneling through realities when this happened. You might want to check everything when you get home and see what details have changed.

[@MrTomtomtest]

You are stuck in a timeloop, doomed to only watch a few minutes of the video.

[@sauron4481]

There was an editing error at the start that got fixed

[@Omar-em7rl]

at 0:22 he got cut off before showing the intro thingy, bad editing, PBS Space Time actually looks at the comments, so all you guy's voices are being heard, different for once....

[@TS1336]

They fixed a couple of glitches of the previous version

[@DorianLust]

Question: Does the Local equation assume it starts from a singularity? What if it didn't? How big would the initial universe need to be to make the two equations align?

[@manskiptruck]

This is great and exactly what I’m doing in my undergrad right now. I’m basically listening to my report, laid out much more nicely

[@benr3799]

This is the most profound video I’ve ever seen on this channel, thank you for the curiosity :)

[@jeremykaschmitter3502]

Where can I get the shirt you're wearing in this vid?

[@TheGreatGarrus]

I want one too

[@Sinnbad21]

I second that question!

[@Ni999]

Adult Galileo "Sup?" T-Shirt | AMNH Shop shop.amnh.org/adult-galileo-sup-t-shirt.html $24.99

[@TheGreatGarrus]

@@Ni999 You truly are the King of Kings

[@fantasick8880]

Google.

[@RandallStephens397]

A shame y'all didn't take the opportunity to recognize Chandrashekar who did the math to figure out the critical mass that makes IA supernovae luminosity so highly predicable--and for whom the Chandra X-ray telescope was named for.

[@albertconstantine5432]

Knowing members of the Chandrashekar family, I can say that they are both immensely proud (and often engaged in the fields themselves), but also accustomed to this all-too-frequent lapse.

[@WestOfEarth]

Matt has spoken about this before in previous videos.

[@rationalmartian]

Not too mention the Limit of his. The Chandrashekar limit on mass sizes, determining what will then later happen to the star.

[@Calex23]

The Crisis in Cosmetology

[@TheCimbrianBull]

ROFL! 🤣 😂 😅

[@pseudoname3159]

Like oh my god everyday's a crisis in the cosmetology department sister

[@Jossandoval]

Your mirror?

[@TheManglerPolishDeathMetal]

😂😂😂

[@quill444]

Tin Foiled Again!

[@enterprisesoftwarearchitect]

Wonderful show! I thought you had run out of subjects. I was sooo wrong. You have surpassed Gabe. Incredible feat!

[@victorjcano]

He does a remarkable job of explaining the topic. Thanks

[@Cliff_P]

Oh it's back! I thought the crisis was over, But I guess it's back again.....

[@aspektx]

But guess who's back... kzbin.info/www/bejne/goOYc4yQn9qLg7c

[@PainterVierax]

Like MM, We thought it was censored by the FCC again.

[@quill444]

Trending Towards Uncertainty

[@butHomeisNowhere___]

Best part of the week! I love this channel

[@bljah123]

Perplexed: if light from distant galaxies travels to us longer, that means they are older than the near ones. So if far away ones recede faster than near ones, doesn’t than follow that in the past they receded faster...?!

[@weatheranddarkness]

which makes sense since we know the initial expansion was MUCH faster than it is now.

[@kevinmakwana]

I love how this channel doesn't dumb things down!!

[@MorbusCQ]

Best series on KZbin

[@kirkdecker6228]

The best channel, IMO, on KZbin. Perhaps the whole universe is a vast fractal pattern operating with a Heisenberg uncertainty principle. Or it's a vast living organism. I always feel like I ate a ton of shrooms after watching these videos. Thanks for the great videos!!

[@Kwisatz_HaderachXIII]

🍄

[@ivangirardirodrigues6452]

what about h0 calculations by the gravitational waves?!!!!!

[@trashman9948]

Gravitational waves would be accurate, but they are too difficult to measure. Hell, we only measured it the first time because 2 black holes collided. That doesn't happen often, and definitely not often enough to conduct research with.

[@badlydrawnturtle8484]

They're working on it. Give it a decade or so.

[@badlydrawnturtle8484]

@MIDBC1 Gravitational waves would be red-shifted in a similar manner to light waves.

[@Xanoxis]

@@badlydrawnturtle8484 How can you measure "redshift" of a spacetime itself?

[@gigakoresh]

@@Xanoxis If we have some way to estimate the original object's mass, we can use that to measure the expected gravitational wave wavelength against recorded one.

[@ObjectsInMotion]

I finally know what he was trying to say 0:22! I was so lost, was it Uniform, was it University? Unibomber? Uniqlo? Who knew? Glad that mystery is finally solved.

[@jovetj]

Question everything.

[@GregorioGrasselli1972]

I have two questions I should have made before. Was matter hot and emitting light also after the CMB? Im' trying to understand if that flash was an instant or an era. CMB we see now is from the matter 13.4bly away from us, that is a 2D picture, but 1by ago we would have seen another 2D picture from another layer of matter, right? Could that be different from the current one?

[@sillywizard6220]

Sup? Thank you PBS and Dr. O’Dowd for another great episode of... ...Space Time!

[@b.griffin317]

how different would the inputs in the CMB modeling have to be to get a result from the other method? has anyone considered this approach?

[@chmeee9562]

That is a great question. The answer to that would give good insight on how sensitive each measurement is.

[@kreynolds1123]

A red shifted photon has less energy than if it is not red shifted. Assume concervation of energy, where does this energy go? If i throw a ball strait up, Kinetic energy is converted to potential energy. If redshifting photons is converting kinetic energy to potential energy, what does this mean on a cosmic scale? And if there is no effective way to converr that potential energy back to kinetic energy, does that change our notion of conservation of energy in regards to the universe?

[@WisdomVendor1]

If you consider the photons in the direction of motion which would be blue shifted, then the total energy of the system is conserved.

[@atlmyk]

I know enough to know I know nothing but I am going to guess the lost energy goes to the 'energy of the void' powering the expansion of the universe.

[@fluffy_tail4365]

In the full formulation of General Relativity conservation of Energy is not absolute. After all time symmetry (The Noether version) is broken, meaning energy isn't conserved. In layman terms the energy is stolen by spacetime itself, similarly to EM fields; however, contrary to standard field is impossible to define a proper energy density for spacetime, due to the broken reference frame thing. This doesn't mean that the universe is broken in GR, simply you can't use energy conservation to solve equation of motion anymore and you have to rely on the full GR tensor magic. There is some more info here by actual physicists: motls.blogspot.com/2010/08/why-and-how-energy-is-not-conserved-in.html, physics.stackexchange.com/questions/35431/is-the-law-of-conservation-of-energy-still-valid

[@skandragon586]

There was an episode on this... Basically on cosmological scales the conservation laws do not always hold because the size of the universe is not constant

[@skandragon586]

@@WisdomVendor1 they are also redshifted from the expansion of space. When observed from far enough away even stars moving toward us are moving slower than the expansion

[@crsmith6226]

Do you think you could ever do a video on “Iron Stars” which Isaac Arthur talked about as the final future of stars if protons don’t decay and the “Big Rip” doesn’t occur

[@coopergates9680]

They have. kzbin.info/www/bejne/h5iXp5VjgK1ofJY

[@coopergates9680]

@@c7042 This is for stellar remnants without enough mass to collapse to neutron stars.

[@shahidafwan1102]

Your lectures enter in one ear and go out from another

[@Ganjor420]

16:00 if a CPT inverted universe isn’t the same as ours, there has to be a way to know witch one you are in. Cause if you really can’t tell wich on you live in, there can’t be any difference at all, so it’s the same by definition or not?

[@jamesdietert1998]

Can you explain why we're so hung up on the notion that dark energy has remained constant since the release of the CMB? You mentioned the possibility of variable dark energy almost in passing, but considering how little we actually know about it, this seems like a rather simple theoretical explanation for the discrepancy in measurements.

[@pseudorandomly]

+James Dietert Yes, it could be that dark energy is not constant, though that wouldn't be the simplest view. Arguably, that simplest view should hold absent observations that indicate otherwise. And, as this video points out, there are other possible explanations of the discrepancy. The goal is not simply to find *an* answer, but to find the *correct* answer. It may well turn out that dark energy really _is_ constant, and some other explanation obtains. Don't view it as being "hung up"; look at it as preferring the most conservative explanation.

[@Darryl_Frost]

I'm hung up on inventing new physics to make your model (sort of work), Dark energy, the energy that gets stronger the further away you are! ON what basis of reality is that based on?

[@exoplanets]

Just had a Déjà vu..

[@johntate6537]

Again?

[@Trias805]

That's a glitch in the cosmological constant. It appears when cosmologists are changing something.

[@MeadowBrook2000]

invariance of scale is the answer

[@EscapeMCP]

I think it was a parallel universe brain thingy colliding with ours for a few minutes (of our time... it lasted millions of years in the other one).

[@peterbonnema8913]

You just violated T symmetry

[@swbusby]

I have much greater trust in the directly observed supernova measurements.

[@chmeee9562]

Yeah, the CMB number relies on many stacked calculations and assumptions. I agree the supernovas seem more robust.

[@traviskelsey6674]

It does seem there's less *physics* involved in that measurement. The fact the CMB measurement is so close is actually somewhat reassuring, I think. It suggests, at least through one metric, that the assumptions made about the nature of the CMB might not be utterly flawed. But there are two potential counters to this assumption: 1) Our understanding of the CMB is flawed and the closeness of the results in purely coincidental. 2) The assumptions and calculations involved in understanding the CMB are potentially biased by a need to conform to existing data and theories (in other words, they fudged the theories to make the numbers work, even if unintentionally). I don't think either of these two are highly likely, but they -- the latter in particular -- concern me a little. I'm no physicist. But Matt's explanation of how the CMB is understood and the h0 constant is calculated from it felt like they were making some risky assumptions that they are only so confident in because the math seems to work out.

[@Biomirth]

Thank goodness we rely on experiment, math, and logic rather than trust and faith. \#bringontheenlightenment

[@maxcovfefe]

A crisis in cosmology! Hold on! Saving to "watch later" playlist because I need to call some friends and get some beer for this!

[@stewitr]

It amazes me that despite constant failure to find any dark matter/energy signal in any experiment, it's still firmly rooted in the mainstream as absolutely correct.

[@BridgetMayAljasser]

About 8 years ago, I told my husband dark matter was a lazy scientist's explanation. If something doesn't fit within their hypothesis, they make up crap without evidence rather than doing the hard work to find the truth.

[@cosmicmutant33]

This universe could not contain the amount of information of this video so they had to compact and reupload it

[@perfectwhine742]

It makes me sad that there's a universe where I'm a crackhead and my parents are crying, wondering where they went wrong

[@birdmw]

Is that this universe or a different one?

[@orlandovazquez8694]

This solar system,let alone Earth,is a miniscule insignificant dot compared to the universe. Look up smbh, quasars,exoplanets etc.

[@perfectwhine742]

@@birdmw lol XD

[@perfectwhine742]

@fynes leigh Sounds like you need some friends Fynes!

[@perfectwhine742]

@Frank Sears You're so clever!

[@bananabourbonaenima]

Could you explain the significance of the Hubble Ultra Deep Field?

[@mullymloo]

????? Its basically a photo of very long exposure of very distant or very fait objects. The significance?? Well, you'd have to specify what you mean - specific to what.

[@bananabourbonaenima]

@@mullymloo What does it mean that we see such developed galaxies relatively shortly after recombination? Is that specific enough for you?

[@utkarshpathak9780]

@@bananabourbonaenima it think you told the significance of it in the reply anyway. Well, it helps fitting the time of epoch of recombination and reionization because we will come to know about the oldest of the structures in the universe from a deep field. My field is not cosmology so i don't a lot about it.

[@chrissearle23]

This so very exciting.

[@picpac2348]

I've just seen the Joe Scot's video on quantized inertia and it got me hooked. Please do a video on the subject. I'll do some reading in the meantime so I'm ready for your in depth suff when you get around to it.

[@SupLuiKir]

If the Hubble Constant is the rate of expansion of the universe, then wouldn't it be evident that the Hubble Constant in the distant past would be significantly smaller then than it is now since the rate of expansion is accelerating? What if both values are correct?

[@lunkel8108]

Both values are the Hubble constant for the present day.

[@dcsignal5241]

But aren't the measurements based on observations of objects as they were in the distant past?

[@calebmatthews2026]

My thoughts exactly.... Just wasn't able to articulate them lol.

[@pseudorandomly]

@@dcsignal5241 "... based on observations of objects as they were in the distant past?" You're correct. The explanation is at 9:10 in this video. Essentially, you start from the conditions at the time of the CMB release and calculate forward to get the present-day Hubble constant. The Hubble constant was much _larger_ in the very early Universe than it is now; gravity spent several billion years slowing it down before dark energy began speeding it up. (If you're troubled by the Hubble "constant" being a changing value, note that many prefer to call it the Hubble _parameter_ instead.)

[@SupLuiKir]

@@pseudorandomly I agree, 'parameter' is a far better term as far as linguistic specificity is concerned.

[@catharsis21]

It would seem that the "constant" would prefer to be a variable.

[@BridgetMayAljasser]

The only constant is change

[@grokeffer6226]

I enjoy these videos, but they make me feel dimmer than a brown dwarf, sometimes.

[@Sinnbad21]

Grok Effer that’s dim af.... but I feel even dimmer.

[@Scanlaid]

@@Sinnbad21 black hole dense

[@kenlieck7756]

Racist! Sizist! Comparative, um, luminance... ist!

[@scotchfillet]

So called intelligence pales into insignificance when compared to wisdom. Wisdom is a much more useful thing. You don't need intelligence to have wisdom.

[@grokeffer6226]

A wise man once said... something... I forget. I wasn't really listening. Regardless, Joni Mitchell [who IS wise] said "We are Stardust." I'm not sure how that relates here, but there you have it. Thank You.

[@johnfarris6152]

PBS has always been the Unknown Soldier!

[@BertVerhelst]

8:30 the release of the cmb. Did this happen in an instant across the universe or did it happen somewhere first (eg at the outside of the universe) and propagate inward? Are there any calculations on how long this took? Would the propagation speed be limited by the lightspeed?

[@hermannvargens]

It happened as the universe got cooled. Yes, there are. For sure.

[@Recon777x]

What happens if one of a pair of quantum entangled particles falls into a black hole?

[@sealionroar]

They do the fork in the garbage disposal

[@howdy832]

They probably disentangle. That shits real sensitive

[@Recon777x]

@@howdy832 Really? Entangled particles can disentangle? Hmm.

[@howdy832]

@@Recon777x Yeah, its a pretty big problem for quantum computers. They have to be in an extremely noise-free environment to stay entangled.

[@davewilson13]

Once a measurement occurs, or an interaction, they are no longer entangled.

[@dt28469]

"The velocity part is relatively easy" Pun intended?

[@complex314i]

Negative mass would be interesting. Personally, I really want tachyons to exist. That way the universe would have particles with imaginary mass.

[@StephenGillie]

Do you have a null hypothesis (H0) involving the Hubble Constant (H0) and model trains (H0) in peroxide (HO)?

[@Jolafunk]

You are our every eye and ear to what our brians needs to understand

[@Jolafunk]

@paul w Unplug your ears

[@Jolafunk]

@paul w Hammer your computer! FLAT

[@Jolafunk]

@paul w Latest brain mainiac. I got lots of knowledge are you satisfied now? Calculate the largest mass that could produce a star?

[@meizhongbai]

We expect other galaxies to be all moving away at exactly the same rate, but if our current model is wrong then we might observe slightly different rates. For example, if massive objects in space are free falling in 4 dimensional space (5 dimensional space-time) then depending on the mass and how close it was to other massive object(s) when it's mass became significant enough to fall away instead of fall towards another massive object, and many other potential factors, objects could be moving away from each other at slightly different rates. It is also possible that space isn't expanding then, and all massive objects are free falling in 5 dimensional space-time.

[@jaimemaldonado4152]

Dark energy is the fish trying to decifer how gravity affects tidal waves without yet knowing about the existence of water .

[@lastmanstanding5423]

wait wait wait... the universe was playing a sound when it was opaque...? that's soooo cooooool... _the song of the baby universe_ (cry?) nice...

[@JgHaverty]

They are called baryonic acoustic oscillations. Not particularly lovely to hear lol

[@Bob-zx7io]

I like listening to these vids because it make me feel smart, even though it's all over my head :-)

[@Miss__Understands]

They make ME feel stupid!

[@GiI11]

This is such a great channel!

[@leyasep5919]

Now we have to measure the speed of dark !

[@ChaosKeep]

Gravity Waves - Nature of the Speed of Light, Dark Energy and Dark Matter - Musings of the most dangerous type - with only partial knowledge. Listening to Dr. Krauss on Penn’s Sunday School talking about gravity waves got me thinking. The fact that gravity waves have now been shown to exist, this seems to have some interesting implications to me. I admit that the following thoughts have probably been thought of by smarter minds than mine, especially since my degrees are in Geology and Planetary Science with a minor hybrided between Physics and Remote Sensing. However, in listening to this I was using the following hypothesis and was predicting what some of the possible reasons for the differences in H naught could come from, specifically Dark Energy not being constant. Gravity waves are the physical effect of the movement of mass through space-time. To me this may help explain the speed of light and the difficulty of reaching it. If a gravity wave is created every time a mass moves, and given that presence of a mass of matter will bend space-time, then moving matter not only should create gravity waves, but try to drag the frame or fabric of space-time with it. The faster a mass tries to move the more it drags on the frame or fabric of space-time. This drag then would act as a form of inertia that increases as velocity increases. This would explain why you need a nearly infinite amount of energy to accelerate a mass of matter to the speed of light. It also may explain the speed of light itself. Many experiments exist that demonstrate the duel nature of light, particle and wave. Classically, the mass of a photon of light is essentially zero. But what if it really isn’t? What if the mass of light is infinitely small, say one divided by a googleplex, with the result raised to the power of a googleplex. And it is the mass of a photon of light that limits its speed to the speed of light because of the gravitational frame drag inertia created by the moving light. IF true, then light, as it moves through the universe is attempting to drag the fabric of space time with it. With light literally moving through the universe in every direction, could light be responsible for stretching the fabric of space-time through a drag force? Would that mean that it is the frame drag of light that is what we call Dark Energy? As the fabric stretches, in all directions, then the light energy fills it out again, keeping the universal constant energy density. Conversely, we know that matter warps space time towards it. But we also know that we see gravity as being too weak. Could it be that the force of gravity is, in part, dissipated in fighting the frame drag expansion created by light? Could it be that Dark Matter is not an exotic form of matter, but the effect of gravity on the fabric of space-time? If true, then if we could minutely measure the amount of red shift due to expansion of the Universe, then it would seem that the amount of expansion, and hence the amount of red shift should differ for say the area around a star in intergalactic space, and stars orbiting close to a galactic center super massive black hole. This would seem to explain some, if not all of the difference as you would need to consider a variable of energy density between us and the object being measured to determine H naught.

[@revolution51]

I thought that parsecs was just an average sexual encounter between two golfers.

[@DragonsFrogs]

revolutionpm 4/10

[@stevenpdxedu]

@@DragonsFrogs In my area the metric is bogysecs. Or 2√parsec X handicap + age.

[@RLomoterenge]

Subpar sex

[@faybrianhernandez2416]

Brilliant!

[@jacquesstoop2587]

MEGAPARSECS

[@rayzorrayzor9000]

09:14 "How do you get the Huuble Constant from all of this ?", i think that question overshadows the work that must have gone in to actually find out the answer deemed as "All of this" , i for one was "blown away" , by "All of this" , when he explained about the battle beween light and gravity it made me soooo thankfull that im alive in a time where information is just a "click" away ! ! !.

[@yukterez]

The image of the CMB at 7:28 is not taken by the Planck satellite, that's the old WMAP version with much lower resolution.

[@AmoebaMan23]

Let's be totally honest here: what are the odds that the accuracy on these competing calculations is just not as good as the scientists want to think? Especially with that second method, there must be so many variables baked in that I really struggle to believe a +/- 1% accuracy.

[@michaelsommers2356]

Read the relevant papers and point out their errors.

[@soheil527]

@@michaelsommers2356 there is a reason why we still have so many competing views because the scientists are at loggerheads whether their inferences and calculations are accurate. it is al hypothetical nothing else

[@soheil527]

@@michaelsommers2356 there are several stars going supernova over and over again which the scientists cannot explain

[@michaelsommers2356]

@@soheil527 Read the relevant papers and point out their errors. Be specific.

[@irokosalei5133]

@@michaelsommers2356 wow you beleive in paper more then man? stupid!

[@moeharvard]

Another reason for the crisis in Cosmetology is that there aren't enough qualified Aestheticians

[@lololman]

"Speed of Dark" lol

[@Tomer-Barak]

The cosmological constant is not constant. It seemed constant because we have only one/two data points when we describe the observable universe scale. There are dynamics in the observable universe scale, just as with any scale, and new forces, etc. All we can get are >effective< field theories. We should embrace it.

[@ATLJonathanH]

I still watch this channel despite having 90% go over my head.

[@KantiDono]

What about a direct measurement of the Hubble Constant? I know that sounds silly at first glance, but it's not strictly impossible: In the last 40 some years the Voyager 1 space probe has been flying away from us, it should now be about 2 cm further away from us, due to the tiny sliver of space between us expanding during that time, than if space was not expanding. This is tiny on an astronomical scale, but a readily understandable and measurable distance. Though we know Voyager 1's position and velocity relatively well, all things considered, it's not nearly precise enough for that sort of measurement. But it should be possible to construct an experiment that would be capable of measuring the infinitesimal additional acceleration we would observe of a space probe flying away from us on a human timescale, and not only from analyzing million-year-old photons.

[@johannageisel5390]

I don't think the space expansion is measurable within a galaxy. Because gravity dominates on that scale.

[@X3MgamePlays]

I like your idea. But the Voyagers don't have that accurate measurement tools.

[@robertmolldius8643]

68 km/s/Mpc = 2cm/s/Ly. Voyager is not that far out.

[@KantiDono]

@@robertmolldius8643 Not 2cm/s. 2cm _total_

[@deusexaethera]

Why do cosmologists talk about the "moment" when the CMB was released, when the hotter denser regions of the universe must've taken longer to cool enough to release their CMB radiation?

[@katzbird1]

Shawn Elliott According to Spergel et al (iopscience.iop.org/article/10.1086/377226/fulltext/), it took about 115,000 years for recombination to occur ("Thickness of surface of last scatter" on table 2). Although this seems like a long time for us and was 1/3-1/4 the age of the universe at the time, when looking back, that difference is negligible. The current estimate for the age of the universe is about 13.8 billion years. A difference of 115,000 years is only an error of 0.00083%. I'm sure that cosmologists take this into account. There are too many variables in these measurements to fit into a 20 minute video. But to the layperson, 115,000 years may as well be an instant.

[@TheRABIDdude]

Marc Katz so Shawn Elliot is right? Those red speckles in the CMB were actually released up to 115,000 years after the dark blue speckles? That's very shocking if so!

[@soyounoat]

Pop Cosmologist: "80% of the universe is made of 'dark energy' and 'dark matter', and we don't know what it is - nor do we know the exact rate of it's expansion" "But we CAN describe the exact state of the universe at each fraction of a second after the big bang"

[@capusvacans]

@lostman33 Yes, someone will be able to type the entire proof for all of that in a youtube comment. I mean, how complicated can it be, right? There is a reason why ppl study their entire life to figure out this stuff. You have 2 choices, you either join them, or you trust in the math they do, or you come up with something else, which of course you then also need to prove. I wish you good luck.

[@capusvacans]

@lostman33 Are you seriously bringing up the "it's just a theory" nonsense? Really? Ppl must have explained to you 1000's of times what a "theory" means in science, so I won't bother reiterating that. You equate the terms hypothesis and theory, eventhough those things are completely different things in science. Also, even if it were all just based on a hypothesis (which it isn't), that would still not be proof of it being wrong. Everything we know started out as a hypothesis, and only when proven correct does it become a theory, or a part thereof. But considering that you bring up the non argument of "it's just a theory" i can assume that you have no scientific schooling. So please, go learn cosmology, and then disprove it. In your mind it should be easy, as it's just a theory, right?

[@capusvacans]

@lostman33 Nope, you don't seek truth, you seem to dislike reality and are looking for another one. The world isn't one big conspiracy. And science, due to the millions of ppl involved from all different countries, cultures etc. is the one thing that we can actualy trust because it doesn't involve politics or monetary gain. Any scientist that makes up nonsense to fit a narrative will instantly get debunked by 1000's of others. And they don't use arguments like "it's just a theory", nope, they use maths, experimentation, observation etc. And the best of all is, if you really really want to know, you can check it all for yourself. Of course, this requires effort and study, and a willingness to ignore your "gut feelings". But yes, i know, it's much easier to just go with your gut, although this does ensure that the world won't make any sense to you. I honestly hope that you really go study in some scientific field so that you can behold the beauty of it all. (and nope, reading 2 articles and watching some stuff on youtube does not equate studying).

[@DarthObscurity]

@lostman33 You are using a device, right now, that would not work if relativity were not correct. The very hardware it uses is based on the mathematics of the theory. "I am a truth seeker" Lmfao

[@nik8099]

@@capusvacans Well, you believe in an external objective reality that is predicated upon a linear materialist perspective. Scientists are just as ideological and dependent on funding as others. Paul Feyerabend realized that scientists were becoming like the religious.

[@andrewwestcott9172]

Re: 1:12, I've always wondered what the observational difference is between a distant object getting further away because the space between it and us is expanding, and if that object was just travelling away through static space. Anyone know?

[@MO-pn8ip]

Hi here!!! I don’t actually comment...but am sooo amazed of ur channel (its z best )....but i would really like if u made a video about “fringe theory” ...am sooooo exited to see that (cuz obviously no one can do it better than u ).......am waitin ....peace!!

[@MO-pn8ip]

That theory is actually called ...”quantized inertia “!!!

[@mikeo759]

It's possible that the universe is a woman and is just lying about her age

[@cloudpoint0]

No, we have a birth certificate to corroborate her age claims. Several in fact that all agree. And all the surface wrinkles make her age difficult to hide.

[@mikeo759]

@@cloudpoint0 If you look deep enough into her you'll find a great void inside. Just cold and emptiness.

[@cloudpoint0]

@@mikeo759 Sounds a lot like my girlfriend (someone my wife frowns on).

[@sarthakmunda3914]

There's so much 'dark' about her, even our best scientist have a hard time figuring her out

[@kotodamamidnight412]

Mmm, yea unlikely. Too many holes

[@RobertHildebrandt]

0:29 "In 1929, Edwin Hubble discovered the Universe" I wonder where people lived before xD

[@truthspeaker5717]

on a flat earth BOOM BOOM

[@bmbmw69]

Maybe the expansion of the universe is the physical influence of time.

[@ablebaker8664]

...or, time is the way us lowly 3-landers perceive a forth physical dimension that we are only able to explain in terms of the fact that our keys aren't where we left them at a place called "this morning" and our doctor wants to do a follow-up at a cartesian coordinate called next Tuesday at 3:30 PM.

[@bmbmw69]

@Hose2wAcKiEr what do you mean?

[@ablebaker8664]

@Galva Tron It doesn't have to be matter for the rate of passage of time to increase or decrease. The greatest amount of change that any human being has ever directly experienced are the Apollo crews. Yet, the velocities of those ships was such an insignificant fraction of C, that they didn't experience more than a few microseconds difference over their entire mission. The only way you would notice the difference would be if the few nanoseconds of time dilation of GPS satellites was not accounted for, your cell phone's Google Map directions would be useless to you.

[@bmbmw69]

@Galva Tron space isn't matter but it is connected to time...space-time...I'm just saying that the physical expansion of space could be the effect of time on it.

[@ablebaker8664]

@GamingTV Which is inconsistent with actual science. The universe is expanding (by observational evidence). The expansion is accelerating (also by observational evidence). Functionally science illiterate YT posters not withstanding. Unfortunately the skills required to understand what new inquiries actually mean, are the very skills that couch potato commenters are lacking. This implies to the functionally illiterate that in the absence of comprehension, that they must be experts by virtue of being unable to grasp that they don't have the skills to understand how little they understand.

[@sylviapapp8812]

Thank you Matt !

[@MtnTow]

This may be the best expansion video available. Thank you. I feel that the expansion of space should change certain things like electron flow, mass. And a thought that just occurred to me is, could space at near the limit of expansion get weak and cause a tear in a gravity well? Also, i feel redshift interpretation is not completely uniformly accurate and if we can resolve that, we may solve a few issues.

[@charlestwoo]

I wonder what happens when dark matter or a sterile neutrino interact with a black hole, can they?

[@lunkel8108]

A sterile neutrino would just fall behind the event horizon and add a tiny bit of mass to the black hole. Probably the same for dark matter.

[@Trias805]

I don't see why they should behave any differently than anything else.

[@firebladetenn6633]

Penr0se The objects you’re referring to don’t interact with electromagnetism. Gravity still affects them. A black hole would have no problem eating them.

[@charlestwoo]

@@firebladetenn6633 are there any theories that predict non gravity interacting particles then? is a graviton one of those?

[@firebladetenn6633]

@@charlestwoo I've looked hard. there are certain types of exotic matter that come close. If they are absolutely unaffected, then it would depend on the curvature of spacetime, and the geometry of our universe. They could go back in time, or into another universe, or simply pass right through. That said, the more likely scenarios involve negative mass particles, which, depending on the theory, seems to either be shot away from the black hole, or...sucked directly in normally, because negative mass and its interactions with normal mass is...complicated.

[@ZepakuKiros]

I thought i just watched this

[@moeharvard]

The crisis in Cosmetology is because we don't have enough good schools for it

[@stevebrindle1724]

I thought Douglas Adams sorted this in Hitchikers guide to the galaxy! Keep up please space time!

[@Ralwor]

I noticed the use of megamanX4 music in the background of this video and i compliment your choice.

[@carlg5086]

Its plausible that the expansion of the universe is an illusion caused by space-time.

[@papaclanc]

Is it, Carl? Is it really? lmao

[@MosJournal]

Saying "crisis" seems extreme. I initially skipped this video in the recommended videos because I thought it was a creationist video.

[@ominous-omnipresent-they]

Creationists are frauds who'll do whatever it takes to undermine the First Amendment, thus, degrading education and preventing scientific progress.

[@pursuitsoflife.6119]

Hear me out ok, what if, the acceleration is accelerating?

[@joemarz2264]

Then the variable would be (1/t^3) instead of (1/t^2). You follow?

[@maestrosk]

Cosmology should distinguish between those two different statements: 1. "Redshift is proportional to distance". 2. "Further galaxies recede faster away from us." Statement 1 is an accurate, experimentally backed statement. Statement 2 needs a bunch of approximations from statement 1 to be made..... including that redshift is ONLY made of Doppler effect.

[@michaelsommers2356]

The cosmological redshift is not the same as the Doppler shift, or gravitational redshift.

[@arfyness]

Matt I just want to listen to your voice forever. You can read me anything.