Are Dark Matter And Dark Energy The Same?

[@OnyxIdol]

While this paper may ultimatively be flawed, I still think these kinds of things have a place. It's sort of like brainstorming, where you throw out ideas that are in themselves ridiculous, but which can nonetheless inspire people to come up with something that actually works.

[@chrisg3030]

I'm copying here a ridiculous idea I posted to this vid a year ago: "They [dark matter and dark energy] could be the same if gravity were a repulsive force under certain conditions. What if the square of the distance in the expression F = Gm'm"/r² underwent a sudden (and admittedly unexplained) sign reversal at large distances between galaxies so that it becomes a repulsive force, and more repulsive the greater the distance? This sign-flip interpretation of antigravity, F = Gm'm"/r⁻², could explain the increased expansion rate of the universe, currently attributed to dark energy, as distant galaxies are accelerating away from each other due to antigravity rather than towards each other. What about dark matter? In her vid "Does Antigravity explain Dark Matter?" kzbin.info/www/bejne/e5akmKiKoJuSaKc Sabine Hossenfelder says "I have this idea that antigravitating matter would surround normal galaxies and push in on them". Under the sign flip hypothesis this pushing in is due to gravitational repulsion from surrounding but distant galaxies."

[@jeffreyvosburgh2099]

@@chrisg3030 No need for gravity to be repulsive. My idea is much more fundamental, but I doubt the physics community would be open. My explanation would remove any need of dark energy or matter.

[@JoeWithTheHoesBiden]

@@jeffreyvosburgh2099 scratch my last idea I threw around (that's why I deleted my comment) I just realized it can't be correct without invoking some insane equivalence priniciple

[@chrisg3030]

@@jeffreyvosburgh2099 Sorry for the late reply, but KZbin is a bit patchy about notification. Anyway I'd have thought repulsive gravity is no less fundamental than attractive, but I'm open to your idea. Do you explain it anywhere?

[@jeffreyvosburgh2099]

@@chrisg3030 I don't ......yet. I'm not funded and have a living to make, but soon I will sit down and pull it together.

[@LeoStaley]

A friend of mine says he knows Dr Farnes, and tells me that he himself thought that the main value of his article was to spark interesting ideas among physicists, and that he himself wasn't too vested in the theory as presented in the paper.

[@Chris-pt3ri]

the thunderboltsproject youtube chanel

[@dangiscongrataway2365]

I like that idea, seems like nobody is trying any new theories to explain the universe, at this point it seems right to do so

[@LuisAldamiz]

That's what I got from the paper myself: why must we understand gravity in a "mass attracts mass" or "mass bends space-time inwards" and not in a reverse "vacuum repels mass" or "vacuum bends space-time outwards", even expanding it (stretching it like a chewing gum?), or as something more complex, much in the line the paper suggests but maybe less Newtonian and more refined? The whole idea is intriguing and should be IMO understood more as a very elaborate draft than as the final answer to the question of how does gravity happen? That's why it is so exciting: it's not yet it but it seems to point to roughly the right direction.

[@singularity-hf7qn]

I think the same. We're in a position where we need sometimes try some fringe ideas to push our understanding forward.

[@needycatproductions6830]

That and maybe he is also feeling the pressure of having to publish stuff, else he might lose his job/grants :(

[@guillermojrboy3292]

Man, datamining this game is hard. If only there was a way to talk to the Devs themselves.

[@devvanbutler2758]

for whats its worth. I made it to stage 2.

[@PureFilth23]

"The graphics are amazing but the gameplay is terrible." 2/10 IGN

[@Delta_Tesseract]

To talk to the game developers you must first develop your own simulation.

[@brokentombot]

But who develops the developers?

[@guillermojrboy3292]

@@brokentombot It's developers all the way up.

[@MarioAchkar]

I love PBS spacetime. It is one of the most credible and entertaining channels I know with the most accurate and logical information as compared to other science channels. Each episode is very well prepared, studied and conveyed leaving only little room for occasional errors.

[@kobiromano6115]

"Probably not a Negative Mass, Anti-Gravitational, Positive Pressure, anti De-Sitter Space Time" - Can we have that as a t-shirt design?

[@smokey04200420]

It’s obvious someone didn’t watch the entire video.

[@user-wu7ug4ly3v]

Original script: “No”. Producer: “Hmm...I see what you mean, but you’d better fill it out to a full episode “

[@dj_laundry_list]

en.m.wikipedia.org/wiki/Betteridge%27s_Law_of_Headlines

[@Macieks300]

More like "most probably no"

[@user-wu7ug4ly3v]

Macieks300 that was the second draft 😉

[@scp3999]

no more like this is a nerd channel where we require a lil more than just "no"

[@auto514]

"No. ...uh, Spacetime."

[@sny1337]

Every time Matt is about ending an episode, I stop listen to the reasoning and instead only listen for how he is about to end the episode with "Space Time".

[@electrikshock2950]

It's almost as if you did the same thing

[@RedLeader327]

I do this.

[@0mn1vore]

I wish I didn't do that, because his final summation's usually the best part.

[@goalcreaseb]

I'm always so lost that by the end, I am like a child, grasping for anything, giddy with excitement... for "Space Time". (He said it!!!)

[@unknownfact4466]

It's one of the intricate pleasures of being an avid watcher of PBS... Space Time.

[@samhall4117]

“Matt is currently stuck at an event horizon...” Wait, my next week or his next week?

[@TAREEBITHETERRIBLE]

HAHA this is a scientific response as time to him looks different vs time to us, whilst trapped in this EVENT HORIZON.

[@anarchyantz1564]

Yes

[@truecerium4924]

I alwaysthought that "dark" is a stand-in for " we don´t know yet" :)

[@mugwump7049]

Pretty much.

[@Ardjano234]

Actually, that's "funny" or "spooky". Dark just means you can't observe it (yet). Spooky quantum behaviours make no sense at first, but they are clearly measurable.

[@truecerium4924]

@@Ardjano234 "spooky" would be great, it would be the a case for Scooby-Doo :) ;)

[@truecerium4924]

@@GwladYrHaf let´s agree on observable? That would exclude measureable or explainable

[@truecerium4924]

@@GwladYrHaf agreed on every point. BTW what do you think about the interaction of Higgs field, a graviton and spacetime curvature?

[@realitycheck3363]

10:05 anti-unicorns are real. I saw a stallion during mating the other day. Btw, you got the position of the horn all wrong.

[@douglasmcneil6689]

That was a sabre tooth pony. 😊

[@LuisSierra42]

I've seen them too, there's a global conspiracy to hide their existance

[@sidshetye]

It is done. "Dark matergy" it is.

[@_earlyworm]

dark menner

[@tedarcher9120]

Merk. Dettergy

[@Subut]

Detergent

[@vgernyc]

Didn’t Neil deGrasse Tyson call it Fred?

[@DiracComb.7585]

Ted Archer are u trying to ship dark matter and dark energy

[@MaBuSt]

This channel is incredible. This is a great example of how critical conversations in our lab would go when we were analyzing someone else's result, it is absolutely a multifaceted conversation that can be confusing and difficult at times...

[@mmseng2]

I have no training in physics. Some of these episodes leave me blankly staring at the screen like a dog listening to Shakespeare. And I love every second of it.

[@Dragon.gaming_]

Same

[@zweisteinya]

Dogs know what words mean. It is we who can't tell a woof from a bark.

[@Zahlenteufel1]

That ending was very smooth :) I was looking forward to this episode ever since I saw the news on Reddit. I do know some physics, not the least from this channel, but reading physics papers is always so confusing because of all the weird stuff named after people (and also the weird high-dimensional geometry things). Maybe you could do an episode explaining the de Sitter stuff (if they did somebody please point me to it). I was trying to wrap my head around "Emergent de Sitter Cosmology from Decaying Anti-de Sitter Space" and that de Sitter part was the main obstacle for me. Maybe you could even do a journal club on that because it proposes (afaiu) a fourth large spatial dimension which I thought was highly unlikely because you mentioned it in a previous episode (something about that gravity would work along it and that is not consistent with observations). Anyway, great episode!

[@NewMessage]

"Astronomers are the worst at naming things... I mean, Siriusly..." Noice.

[@DeathBringer769]

Is there a club where guys like you and Justin Y. hang out at contemplating your existence?

[@eleodoru]

@@DeathBringer769 GIGLES

[@LuisSierra42]

@@DeathBringer769 They are the same person

[@tres-2b299]

Sirius the star

[@user-bo1bp1jz5i]

In 2077, there is a star named Xæa-12 RRSB

[@PaulPaulPaulson]

Photon-like radiation that wouldn't interact with regular matter would be called dark light

[@jmarch_503]

Dark light sounds like a band

[@Draginea]

@@jmarch_503 Sounds more like a vigilante group of crime scene investigators to me.

[@iruleandyoudont9]

dark gamma rays

[@Chareidos]

Which would need a certain explanation, why these photon-like particles are not interacting within our knowledge about the electromagetic force. I would assume there would be a need of adding more than - and + as charges to attend any reasonable attempt to make "sense" out of it. But I think its a nice catchy word for the next "thing" to discover/suggest! ;) Otherwise, is not already most of the light arriving us actually the darkness of Space, we perceive when we look up to the sky at night?

[@jona5820]

Dark photons are a thing. Well a proposed thing. It behaves a little bit like photons, but in the context of dark matter and might couple the dark matter to matter weakly. An extra gauge boson, which arises from an extra U(1) symmetry... Something something something, many models use this in one way or the other... something something something... I don't know anything about it...

[@kookverslaving]

talk about Erik Verlinde's paper on emergent gravity!!! It's already been over a year and no one has taken it up

[@benefit14snaake]

Fourmarduk666 yes. This. Talk about Verlinde emergent gravity

[@JohnnyAmerique]

Fourmarduk666 Because the recent discoveries of galaxies that contain relatively little dark matter, as well as galaxies that are almost all dark matter pretty much rules out Verlinde’s emergent gravity hypothesis. If emergent gravity were correct, the proportion of dark to normal matter should always be the same.

[@stefanb6539]

@@JohnnyAmerique You made me curious. Got a link?

[@bowiebrewster6266]

Fourmarduk666 YES SO MUCH YES. I study at UvA and everyone’s always talking about his theory but i never hear outsiders about it. Was curious on an outsiders vieuw

[@Lightning_Lance]

Yes please.

[@LizzardRay]

FInaly, after Christmas, could't wait for next ep :D

[@Narutofan825]

Why do you care so much?

[@DavidSaintloth]

This is probably your best explanation yet brother, keep killing it.

[@olbluelips]

I guess it doesn’t end up holding up, but the dark matter simulations are absolutely fascinating! I wonder if a negative-mass particle with the same interpretation could explain dark matter, if not dark energy.

[@DeSpanni]

We need an Episode on Anti Unicorns

[@altrocks]

They're just Unicorns from an evil mirror universe. That's why their horns look like goatees.

[@bcast9978]

Ambicorn

[@archenema6792]

@@altrocks Shouldn't the horn be coming out of it's ass? What's the opposite of forehead?

[@WatchesTrainsAndRockets]

My auntie had a unicorn .

[@julesmasseffectmusic]

Unicorns are Buffalo as they only have one horn (kinda looks that way at least). So whats the opposite of a buffalo? perhaps a lion?

[@mbenke88]

About time you uploaded something. I was starting to get the shakes...

[@vytautasdanielius7058]

Guess you could say all the scientists are in the dark about this one.

[@Trancecend]

Ha

[@RobertF-]

That's probably true, they are, but it doesn't matter

[@roberttomsiii3728]

Lol

[@positronundervolt4799]

Get out.

[@Smerpyderp]

Get out

[@wareshubham]

I have gained so much confidence in maths over the years watching this videos... thenx a lot really !!!!

[@maestroanth]

Dang, ty for this. I remember reading this somewhere really wanted to give it stock, but hearing a good, counterargument that makes laymen like me keep my head on straight. Have to watch the episodes like 6 times though to fully get the counterarguments though lol.

[@bobinthewest8559]

The problem with today’s “journalism”, is that it’s propelled mostly by an insatiable desire to be “first” to “prove” that everything before… was “wrong”.

[@reddarin]

"Matt is currently stuck at an Event Horizon." Aren't we all.

[@LuisAldamiz]

I'm not. Unless you consider the crisis of capitalism to be one.

[@MirceaKitsune]

Could you consider making a video about de Sitter and anti-de Sitter spacetime? I'm still trying to warp my mind around that subject and a proper explanation in your style could surely help.

[@omsingharjit]

yes......

[@ToThisEndWasIBorn]

Hehe WARP your mind. I like that modification to the typical WRAP phrase people use. It is very spacetime-ish. 😁

[@violentinstincts]

Your content is genuinely the best thing on KZbin

[@M4R1093]

This is the best channel on youtube. I've spend most of my summer watching Matt's videos over and over again. Thank you :D

[@christosvoskresye]

Dark Matter = Angels. There were a fixed number of them created at the beginning. Dark Energy = Ghosts. As more and more intelligent life is born and dies, there are more and more of them. It may not fit with supernova observations, but it's the sort of thing our contemporary journalists would run with.

[@Chareidos]

Do not forget to mention, that demons matter!

[@crackedemerald4930]

*_The Illuminatti wants to know your location_*

[@Chareidos]

@@crackedemerald4930 They certainly know me, because I know them already watching me! *tips the tin foil hat* ;)

[@TheCimbrianBull]

@@Chareidos Tin foil fedora!

[@Vasharan]

@@Chareidos Demons are just Anti-Angels. Same baryon number, opposite charge.

[@chrish.7563]

What always struck me as odd with the naming of Dark Matter is that this name already seems to include an interpretation. From galaxy rotation curves or gravitational lensing, we may assume that an additional source of gravitational attraction is needed to explain those observations. Gravity (in either Newtonian or relativistic theory) requires mass. Mass and matter are linked, obviously, but they are not the same. Maybe it would be more accurate to refer to Dark Matter as Dark Mass, since it is the effects of a hidden mass we observe. That this mass is related to some form of matter may just be a premature assumption. Until an actual form of an electromagnetically non-interacting matter is found, that is. There have been a number of theories put forward that attribute the effects of "Dark Matter" to properties of spacetime rather than some unobserved form of particles. Until we know what is what, I'd prefer calling whatever the cause of the observed effects is "Dark Mass".

[@crackedemerald4930]

Observing a non-observable thing seems a bit difficult

[@Chareidos]

@@crackedemerald4930 Which is, as far as i understand and if I am capable to bring it in my words correctly, is been suggested to be 95% of the universe equivalent of assumed/measured Energy/Mass.

[@sabbathguy1]

"Dark Mass" you say.. so basically "Black Sabbath"? I approve!

[@MarxistKnight]

Not to mention that what cosmologists should really always be saying is "we have evidence for a discrepancy in the Standard Model, and our preferred explanation is matter that only interacts gravitationally." That's a huge difference from the frequent, incorrect claim that we have "evidence for missing mass."

[@korykraner7876]

and you constant isnt some form of matter just a void between atoms in a universe were it wants atoms to occupy everywhere

[@AMan-xz7tx]

Him: is dark energy the same as dark matter? Me after 24hr binge: you absolute f$#%ing wallnut

[@while.coyote]

You're going to regret that anti-unicorn crack someday when you finally discover they've been the only thing holding dark matter back this whole time.

[@Moonless_Future]

How has this not become the plot of a Gloryhammer album yet?

[@timmykenny717]

I left a comment on a different video saying something about how Mass might only be the property that any particle feels in any frame of reference but its own as far as momentum is concerned which is of course sometimes comprised of many particles making up an ensemble

[@nicholaspdx2717]

I've been waiting forever for another episode!!!

[@babstra55]

I was kinda surprised this wasn't a 5 seconds long episode. "no." roll credits.

[@dj_laundry_list]

en.m.wikipedia.org/wiki/Betteridge%27s_Law_of_Headlines

[@SilverAlex92]

My favorite badly named scientific thing are imaginary numbers. It took me several years of studying math to understand that they are indeed real, and not actually something we imagined, pun intended, to ease some complex calculations

[@sleepy314]

.... it is one of my irritants, too -- such a bad name. 'complex numbers' will do just fine. At least with quaternions when I talk to non-mathematicians I usually only get a blank stare instead of silly metaphysics.

[@crackedemerald4930]

We should have heard Gauss and called them lateral numbers

[@Ashalmawia]

I think of them as "2D" numbers

[@danieljensen2626]

I mean, in some sense numbers don't really exist, so whether they are "imaginary" as in dreamed up doesn't matter. You could say all numbers are just dreamed up.

[@Treviisolion]

Daniel Jensen True, but then we call “normal” numbers real and complex numbers “imaginary.” It gives the impression that Imaginary numbers are less valid than the Real numbers, even though in a sense the only difference is in how abstract they are, and only the Integers are concrete enough to potentially (albeit tenably) be called “real.” Everything else are just extensions we made to the integers to ease calculations.

[@madhunayak165]

Amazing video!!!! Love PBS digital studios keep up the good work👍👍😀😀

[@RogerOThornhill]

Great idea for explaining complicated science to laymen: briefly introduce a term, then another, then another, then another, then several minutes later string all those terms that we didn't have time to absorb, have only heard once, and then forgotten, string them together in several dense sentences held together by scientific verbs and modifiers that we probably learned in high school but each would take several seconds for us to remember their meanings.

[@danielskaluba5520]

I'm a nobody, but I see one very big flaw in Matt's point of view. It appears that he's assuming universal intracuasality (which in all fairness is the standard assumption of all physics). The assumption of a positive lambda - which is reasonable given the evidence - assumes that the forces causing universal expansion are solely present here in the universe. Our universe appears to be a closed system, but we can't be sure of that. The concept of negative-mass particles flowing into our universe shouldn't be dismissed out of hand. For example, to anyone on the inside of a black hole, it would most likely appear to be a closed system. But it's not given that events outside of the black hole govern it's growth. If one were inclined to analogize the apparently closed system of our universe to the apparently closed system of a black hole interior, I think you could reasonably imagine that the rate of expansion would not be a constant, but rather would fluctuate over time. There might be periods where the expansion appears to be accelerating. But eventually, matter would stop dropping into the black hole, and it would evaporate away. The interior value of lambda for such a system would be variable but ultimately negative. In the same way that Barne's theory predicts a negative value for lambda even though it currently appears to be positive. I'm a nobody, and sure, it's a long shot, but let's not dismiss Farne's out of hand. If the theory points to the possibility of universal intercausality (ie, where exactly are all of these negative-mass particles coming from? And do they have anti-negative-mass particles?), that would be really interesting. We should mull it over a bit before kicking it to the curb.

[@LuisAldamiz]

Well said.

[@Smerpyderp]

Well said

[@rossdtool]

I was thinking on similar lines also (I think). If maybe dark matter /energy is something from another dimension that is somehow affecting (or slightly protruding into) our universe.

[@Hav2bmor]

Very interesting line of thought. Obviously we can't observe the math inside of blackhole but that is a great way to translate the idea of external factors. This isn't an abnormal idea either, we see several theories that add external dimensions or hope to show external forces on our universe such as when dark flow was first brought to the table. Good on you for delivering this thought process so clearly.

[@johnnylefthand6628]

I thought Matt was a bit negative too :)

[@flyingskyward2153]

I can remember dark energy and dark matter a helluva lot easier than stuff like HD 149382.

[@davecool42]

Except for Wired, they really nailed it.

[@PhysicsPolice]

www.wired.co.uk/article/dark-fluid-theory-of-dark-matter-energy

[@kirilkirilov6241]

@@PhysicsPolice Good morning, sir. No, sir, I swear I've never rounded up Earth's gravitational acceleration to 10 m * s^(-2)

[@terranaut]

@@kirilkirilov6241 WEE WOO WEE WOO WEE WOO

[@radbug]

@@PhysicsPolice Hey if you want to really blow your mind, go look up what Nicola Tesla wrote about his own theory of the "ether" / the universe.... BECAUSE HE DESCRIBED IT as a type of fluid with matter riding on it ! HOW CRAZY IS THAT!?

[@soupkitchen467]

@@radbug Wasn't the aether theory debunked in the early 1900s?

[@deathscreton]

Whoever made your end-of-show tune is talented as all hell.

[@EnlightenedEyes11]

Omg you nailed it!!! This is it! It's like you explained my hypothesis exactly!!

[@LeeGoGators]

Great refutation of the flaws in this paper, and recognition of what it does succeed in. The part that bothered me the most about this is the steady-state-esque idea that negative mass would be created continuously, we don't have any reason to believe that IF negative mass existed it would act so differently from nominal matter specifically like this.

[@philsturm4685]

Yeah but it will make my sci fi fake science so much cooler.

[@Laff700]

Yeah, that's my biggest qualm with this theory. It shouldn't violate the first law of thermodynamics.

[@LuisAldamiz]

We know that dark energy is created continuously, so that negative mass is just another name for dark energy, only that also works (not fully but close enough) as dark matter.

[@LeeGoGators]

@@LuisAldamiz That's a pretty large assumption. Why would negative mass behave in this way while nominal mass does not?

[@LuisAldamiz]

@@LeeGoGators - I'm not defending "negative mass" (even if I found the paper interesting in the sense of proposing new but not fully developed avenues), I'm just saying that dark energy is created continuously (per the cosmological observations that gave birth to the concept, now mainstream, of dark energy) or is "constant", at least in vacuum (maybe not where mass/energy is concentrated), regardless of space expansion. All I said re. "negative matter" was referring to the concept as portrayed in Farnes' paper: in the model "negative mass particles" or "negative matter" correspond to both Dark Energy and Dark Matter and almost, but not quite, solve the two problems by themselves. I maybe should have phrased it more carefully but I did not expect misunderstanding, so sorry about the confusion.

[@scienceontheright]

I am seriously annoyed with lazy journalism too!! But not just with science. More so with politics. In fact, I think journalism died years ago in favor of click bait and divisive news :(

[@brightproduction6494]

Trump trump trump is Bad man read article join cause trump trump trump bad person

[@Deppherillion]

that background music... i thought someone was calling me on skype. Great video btw

[@MetroidChild]

Really liked this video, the script and editing made the pacing amazing.

[@joaolucasvieira2979]

I see what you did there with the "EVENT" horizon. You clever chops at space time, never cease to amaze me, with your astrophysicist dad jokes.

[@davencharity]

At the start, I thought Matt said Dr. Jamie Farr. Now I feel the need to work on a theory about the acceleration of expansion being caused by dark energy trying to get ejected from the universe by wearing dresses...

[@timothyernst8812]

Wouldn't such a theory imply Toledo, OH is the Great Attractor?

[@archenema6792]

@@timothyernst8812 Only if you're from Gary, IN.

[@Omnifarious0]

Bullet cluster. How does it explain gravitational lensing that seems to be in the middle of empty space?

[@crackedemerald4930]

A really big magnifying glass

[@Tehom1]

Good point.

[@seankinahan5055]

​@Mr.BigBoss7 With exorbitantly expensive broad spectrum telecopes that have to be launched out of the atmosphere. The air is a lot thicker than you'd think it is. Consider how clearly you can see the moon when looking up through only 1-200km of thick atmosphere. Seattle to even the edge of california is 800km, that's a lot of air!

[@LuisAldamiz]

@Mr.BigBoss7 - You can't see California with a clear sky? I'm perplex, I've flown only occasionally but I still remember seeing the very clear silhouette of Sicily at night when flying to Istanbul.

[@alexanderdaum8053]

There is a bigger problem with gravitational lensing and negative mass dark matter. If dark matter has negative mass it will repel normal matter and will also act the same on photons if there is not another exception. That means gravitational lensing would work the other way around, instead of focusing light around a gravity well, it would be scattered.

[@dennisc583]

3:10 "So dark energy has competing effects - its positive energy density gives it a positive gravitational effect, but its negative pressure is anti-gravitational. In the case of dark energy, the latter wins." So, why exactly is this so? What gives dark energy's negative pressure the upper hand of its positive energy?

[@mihneabudei44]

I expected the conclusion of the theory to be that the negative pressure causes space to expand where the gravitational field is low, but when interacting with the gravitational field, the gravitational force overpowers the negative pressure. But i’m not sure that’s any different than saying that dark matter is a particle. I also wonder whether this reasoning could explain why space is expanding WITHOUT the need of extra matter. So baryonic matter would attract in its proximity, greatly overpowering its negative pressure, but over large scales, its negative pressure might stay constant or drop off slower than the gravitational effect. Interesting.

[@jcreuels]

Thank you for keeping us up ! Excellent work, as always !

[@chrisstargazer5866]

Matt's delivery is flawless!

[@VoteScientist]

A simpler explanation could be that the Gravitational constant is not constant. If it increases in spaces with a high mass density then galaxies would spin faster. If G decreases in space with a low density then galaxies move apart faster than expected.

[@brokentombot]

Sounds fair. It would take millions of years to test that though as we'd have to change position/mass density by waiting for our solar system to move about the galaxy or to send an experiment in/out of the galaxy and relay the message back.

[@Attalai]

happy to be corrected... HA! as if I'll ever be able to correct you (or totally understand anything)

[@deanmichalos6848]

How can we account for the claim "Matt is currently stuck on an event horizon, but comments will be back next week"? Assuming PBS mean they are confident Matt will be back doing the comments next week, this claim seems bizarre! I propose three hypotheses: 1: PBS have a second black hole in their studios which is connected by a wormhole to the one whose event horizon he is stuck on. He just has to stop trying to escape. 2: It's a very small black hole which is expected to evaporate by next week. PBS have built a Dyson sphere around it and are standing by to capture him in the form of Hawking radiation and somehow convert him back. 3: It's a typo. Someone at PBS typed 'at an event horizon' when actually, they meant 'at an event over the horizon'. He is actually on vacation back in Australia. Down under, Christmas and New Year occur in Summer. Everybody there takes about two weeks vacation and goes to the beach. I'm sure Matt would be curious to explore an event horizon in person, but he would probably enjoy some sun and surf in the middle of the northern hemisphere winter at least as much. This hypothesis is falsifiable because it predicts he will have a tan when he returns. It seems the most plausible too.

[@cloud-fronts]

Now that a hypothesis is formed we must propose an experiment! One in which Matt is the guinea pig.

[@deanmichalos6848]

In the next episode, Matt confirmed directly he was in Australia. Curiously, I could detect no tan. However, I realized this would not be a suitable test anyway, due on the one hand to the amount of tan giving ultraviolet radiation that ought to be present in the vicinity of an event horizon, and on the other hand, the success of the 'slip, slop, slap' skin cancer prevention campaign in Australia.

[@lindsayforbes7370]

Many thanks for this Matt. By far the best critique of this paper I've seen (and I've read many) 👍

[@TheInselaffen]

I told reddit to wait for this; PBS Space Time is the arbiter of reality now.

[@palfers1]

Seems to me that gravitational lensing will be exactly wrong - i.e.with opposite curvature - if dark matter = negative mass.

[@Melichorak]

Eh, I might've understood that wrongly. But in this context, the negative mass dark matter apply gravitational force to the photon, which is supposed to be curved, and photon does the same to the dark matter. The photon reacts positively to the force, meaning it will be attracted to the dark matter, but the dark matter reacts negatively to the force, meaning it is pushed away. So gravitational lensing would still work, as it will have the exact same effect on the photon, the only difference would be on the matter, which would react differently.

[@LuisAldamiz]

That's a good point, sir. Gravitational lensing was not considered AFAIK.

[@norman_sage2528]

Snell's law dictates how light bends over long distances through hydrogen, radiation, and dust clouds.

[@DiracComb.7585]

Honestly I must agree, how the heck are scientists so bad at naming things

[@fast1nakus]

typical men stuff

[@Nawmps]

@@fast1nakus okay """""liberal"""""

[@Quintinohthree]

It's just physicists that suffer from this issue. Chemists have a name for literally every thing they can possibly study ever already pre-prepared, and they're unambiguous too.

[@fast1nakus]

@@Nawmps not even close

[@DiracComb.7585]

Tech Tacho which lead to misconceptions that severely oversimplify what the concept means

[@firdacz]

My distrust was triggered by the acceleration of positive-negative pair - that could be infinite power source, or not?

[@davidroddini1512]

Lukáš Fireš That is another reason why the majority of the scientific community doesn’t believe that negative mass is possible under the known laws of physics.

[@Jerom_]

This was my first instinct too. However, when this 'infinite power' was put in the context of dark energy it made me realize an infinite power source shouldn't be out of the question. After all, in current interpretations does it not seem that dark energy literally is an infinite power source? Or rather, a source of energy that does not seem to conform to conservation of energy. When I viewed it like that, I felt like it isn't warranted to dismiss negative matter on the basis of this.

[@Laff700]

No, it wouldn't. The only situation the two masses would indefinitely accelerate in would be if m1=-m2. If that wasn't the mass relationship, the masses would either fly away from each other or bounce off each other and then fly away. If you held the two masses at the same distance from each other, there would be no acceleration at all unless the system's mass was 0. The energy and momentum of the system would remain constant.

[@firdacz]

@@Laff700 Why do you state that there would be no acceleration when it clearly pushesh both objects in the same direction? What would cancel the acceleration? I was, of course, assuming m1=-m2, which would be unstable, but could accelerate to relativistic speeds, creating kill vehicles all over the place. Let us make it stable by some connection - a chain. How would action-reaction work here? Both should try to pull each other, but negative mass would resist, accelerating away... hmm, negative bullet would penetrate any wall? Such negative mass would tear the universe appart. Making the acceleration act in opposite direction then the force produces very crazy effects, nonsense.

[@firdacz]

@@Jerom_ Conservation of energy does not apply to expanding universe, it only works in local non-expanding space (there is no inertial frame in expanding universe), but positive-negative pair would produce (kinetic) energy even in inertial frames (local space, short time where you can ignore the expansion as being miniscule).

[@Exist64]

The concept of an anti unicorn was the one thing I could comprehend in this video. Intriguing 🤔

[@cubicmetre]

I investigated a neat bit of maths at one stage regarding infinite series where I considered the cumulative effect of a set of masses evenly distributed over an infinite space. The result suggested that the total effect of a gravitational attraction between these objects off to an infinite distance would converge to a factor of pi squared divided by six. An interesting result was obtained for any region in the space where there was zero mass. Masses either side of this empty region would experience essentially an anti-gravitational force away from the origin of empty space. This analysis only works for the specific conditions of quantised units of equal mass, all precisely equidistant from each other so I disregarded it as an explanation of dark energy because at the time I was not aware of the vacuum energy and it's relationship with dark energy and so I only thought this effect could be produced by macroscopic objects, which are definitely not equal mass and equally spaced. However, the idea of vacuum energy being evenly distributed with equal mass-energy at every point of space has indeed revived this idea and now I wonder if I may have stumbled across a legitimate piece of the mathematical model for dark energy.

[@troyhenry6111]

Saying negative mass allows for time travel and that is why it's a strong indication that it cant exist is a fallacy. We have no indication that time travel is not possible mor do we have an example of it being possible so our stance should be idk. Now the laws of physics so far allow for time travel; and as the Bell experiment indicates. We need to give up locality or give up realism. It would seem to now stack in favor of giving up locality. If pressured my stance is i dont know if travel is or is not possible, but with theoretical knowledge it seems to be possible though no demonstration has show it to be likely real.

[@AlcyonEldara]

Congratulations for missing the point. We don't know if unicorns exist somewhere, even on Earth (they could be hiding below the surface) so we shouldn't consider that when a friend tells me that he has seen an unicorn, it's a strong indication that he was drunk. And he said "strong indication", not "impossible". So you are showing us the worse fallacy : the fallacy fallacy.

[@troyhenry6111]

@@AlcyonEldara i didnt miss the point, the difference between unicorns and time travel is both quantum mechanics and relativity allow for time travel. Now depending on how you define a unicorn, then it might allow for them also. Also dont talk out about fallacies when you dont know what you are talking about. A fallacy fallacy or metafallacy would be me saying he poorly argued time travel isnt possible so im going to jump in my delorean or police box and hit up my boy Socrates. I pointed out he cant make the claim that it's impossible. Especially when there are hints that it might be possible. I also stated that i am not making the claim that it is possible. The answer is idk either way.

[@petesandwich3246]

Time travel is not possible because time does not exist.

[@AlcyonEldara]

@@troyhenry6111 and since he didn't make the claim, you are calling a fallacy where there isn't any. So this is a fallacy fallacy. Goodbye.

[@troyhenry6111]

10:00

[@RifetOkic]

Can you guys release the OST/ Songs you use ? Thanks a bunch :)

[@dev02ify]

Seconding this. I really want to know the music used starting at 2:11

[@muffinman8744]

Me 3!

[@brokentombot]

There is no background music. I suppose the OST has been released already... in your mind.

[@muffinman8744]

@@brokentombot sir what are you talking about?

[@dev02ify]

KZbin revealed the music from 8:50-10:45 and 13:10-13:52 It's called "Invisible world" by CPM from the CAR 466 Spaces album: www.emipm.com/en/browse/labels/CAR/466 This reddit post that I found has music they've used before: old.reddit.com/r/pbsspacetime/comments/6x820j/for_anyone_looking_for_music_from_the_series/ I know that in at least one case (Janne Hanhisuanto - Water Stories) they've been in violation of the Creative Commons with Attribution license since they didn't list the music. They might want to fix that.

[@Dunkle0steus]

Might be a dumb question, but how come violating causality indicates that negative mass doesn't exist? How do we know causality can't be violated? We thought time and distance were constant for centuries until we looked farther and realized they weren't. It seemed like everything on earth happened at the same rate because the earth's gravity and velocity were very close no matter where you were, so time appeared to be constant. What if we just haven't observed causal violations yet? I mean, causal violations seem pretty messed up and hard to wrap your head around, but I don't think the argument "it can't be that way because I can't understand it" has much merit. The universe shouldn't be beholden to what a squishy lump of flesh can comprehend. The human brain isn't a perfect tool for thinking, it's a solution to the optimization problem of keeping a human alive as long as possible.

[@Laff700]

I agree, that's not a good reason to disregard this theory.

[@Vexas345]

Because there is no evidence to show causality can be broken.

[@Dunkle0steus]

That's not an answer. Again, there wasn't evidence that time was relative until we found it. You shouldn't rule out a hypothesis because you lack evidence for it. You should try to test it.

[@LuisAldamiz]

There are no dumb questions and I find yours very smart in fact.

[@Dunkle0steus]

I have a CS degree, not a physics degree, so I assumed I may just be missing some basic understanding.

[@EnigmaClips]

Im going to watch every single video on this channel

[@SerifSansSerif]

I feel like it's not something to rule out in its entirety, but perhaps something that simply should go back to the drawing board. I feel like the paper is also kind of saying this. It works for a lot of stuff, but the observations aren't quite lining up... I.e. something is missing. Rarely do the observations and data lineup as expected, and often it means revision and more observation, etc.

[@davidmiddaugh47]

I agree with very much of this video and would like to add a .02 as to why a sin wave picture of the universe can help to explain more the universe. preface, this is a personal theory so consider this peer review and tear this shit apart specifically neutrinos, and some of the things they do. Neutrinos are produced by the sun and nuclear reactions. Moving at .9999c (some faster some slower) they carry tremendous energy and there is a lot of them. 65 Billion per second per cm^2. are hitting you right now, that's roughly the size of your fingernail, and they pass right through you unfelt. The catch is they are very tiny, infinitesimal almost, just slightly greater than the electron and moving so quickly it is rare for a neutrino to have a momentum transferring collisions. However in an infinite universe collisions happen eventually. Over time neutrinos have enough collisions to slow down and as they slow down they behave less like a wave and more like a particle, this increases the odds of future collisions as the probability of future momentum transferring collision. Each collision increases the odds of the next[we are, here citation need]. These momentum transferring collisions are what drive the expanding universe or when the universal constant is positive. These collisions would get weaker over time, momentum is conserved, eventually neutrinos slow down. The rate of collisions would get higher but the kinetic energy transferred into the system would continue to diminish as the neutrino slows down over its life. eventually as the neutrino loses the last of its momentum and it becomes a particle, feeling only gravity as it comes to rest. Most of these particle neutrinos would be found in areas of high gravity. At the end of its life. Being free of protons and electrons the particle state neutrino can pack many thousand times over inside an atomic nucleus. When neutrinos come together inelasticly (meaning they stick together) though rare, the probability of such an event would increase as the particle slows down, as the universe ages the probability becomes certainty and as the neutrinos start to coalesce the matter formed would be dense on a scale greater than the atomic nucleus. With the neutrino being so ubiquitous much would come together in space like scattered grains of sand though much smaller and many more. Being free of protons and electrons the matter would not be limited in its size and a quasi nucleus would form from the oldest neutrinos. Each inelastic collision increases the chance and the rate of the next as the particle would increase in size and mass with each inelastic collision. These particle would continue to gain mass faster and faster as more neutrinos reach the end of their life and coalesce. this is when the expansion of the universe would begin to slow down. eventually heat death. Neutrino production has stopped and neutrinos in the particle state are continuing to coalesce faster. The amount of neutrinos carrying high kinetic energy have been greatly outnumbered and the expansion of the universe has entirely reversed every bit of matter is covered in neutrinos everything weighs more and is more attractive, very little to nothing pushing us apart. then crunch. tl;dr the neutrino in a high kinetic energy state can transfer momentum, since momentum is conserved, eventually neutrinos have inelastic collisions and coalesce. While young, the neutrino pushes outwards from its sources putting kinetic energy into the system and the universal constant is positive. When the energy is lost the neutrino only contributes gravity to the system and the universal constant is negative.

[@ankitroy5868]

Man you should get this peer-reviewed

[@Niinkai]

You are spreading childish Fake News about the nature of anti-unicorns (negacorns). Whereas a positive unicorn exists in positive xyz and t dimensions, a negacorn isn't a unicorn that has a horn protruding from its jaw, rather, a negacorn is like a unicorn turned inside out into negative xyz and t dimensions; its positive nature of bone, meat and skin, not to forget the Horn, surrounding a digestive tract is now negated: the negacorn has the exact same, but reversed, shape. The !nega-tract is made of skin, hair, mane and Horn protruding inwards surrounded by muscles surrounded by bone surrounded by organs! The negacorn taking the negative form of unicorn, but with skin made of the digestive tract and galloping backwards through time!

[@robertdaw3364]

Wouldn't a unicorn with negative xyz and t dimensions just be an upside-down-backward unicorn? There's no reason why inverting the spacetime dimensions would perfectly invert a unicorn along its digestive tract. The closest approximation to what you're describing would be a spherical inversion that would create an inside-out geometric opposite of a unicorn shape. Parts of a normal unicorn that stuck out the farthest from its center like the head, legs, and horn, would be dimples sticking inwards on the negacorn.

[@Niinkai]

An elementary mistake! Ask your self, how would the unicorn be turned into negacorn and back? Not even counting the axis of time, turning a unicorn into a negacorn through your method requires three actions, for mirroring each spatial dimension. True negacorns require only one: though hard, imagine reaching inside the unicorn, all the way through, and "pulling" the negacorn into existence. Expressed in algebra: if xyz=1, your method is trading the sides, while my method is simpler xyz=1 |•(-1) Do not doubt the negacorn

[@NoOne-bm1vy]

Man, that LSD kicked in hefty :-)

[@archenema6792]

@@Niinkai But what happens to the negavirgin?

[@Niinkai]

@@archenema6792 they continue playing negaFortnite

[@alexanderkrizel6187]

So, something we don't know anything about may, or may not, be the same thing as something else we know nothing about? Cool!

[@whocares2087.1]

We just came out of the cave. 😔

[@stefanb6539]

We do know quite a thing about that stuff, we just can't explain it.

[@alexanderkrizel6187]

@@whocares2087.1 LOL! Not too far from the truth!

[@alexanderkrizel6187]

@@stefanb6539 I think it was Einstein who said something like: "If you can't explain it to a 6 year old, you don't fully understand it".

[@stefanb6539]

@@alexanderkrizel6187 "fully" being the key word in that quote

[@robertbrown2728]

Thanks for these posts. A lot of it is very hard for me to understand but I get a very pleasant feeling of synapses being re joined as I watch.

[@paulporter5853]

Awesome video! One of your best yet! I didn't hear any mention of dark flow in this video which may be the death knell of this new paper but it is a very interesting paper and worthy thought experiment none the less! Cheers!

[@Mernom]

What I don't like about this theory is that it produces perpetual motion machines and paradoxes left and right. Place a clump of normal matter in front of a clump of negative matter of the same absolute value, and you got yourself an infinitly accelerating object that does it without any other energy imput. If you try to push a clump of negative matter, it will push back insted of responding normally, which increases the force with when it's being psuhed, which increases the force with which it pushes back... Esentially just feather touching it will immideatly cause it to shoot off in the direction it was touched at. Or just putting it on the table will cause it to crash to the ground, accelerating the more it resists to it's motion.

[@idowhatiwantdowhatisaygoog2361]

Since Dark Energy is already observed to be energy created from nothing I think you will just have to come to terms with the fact that any explanation for it will also have to include energy created from nothing.. So you can't discount the negative mass explanation just because you don't like how it allows perpetual motion.

[@Laff700]

I find it works well when the collisions are elastic. I've made some physics simulations with negative mass BTW.

[@petesandwich3246]

> and you got yourself an infinitly accelerating object that does it without any other energy input. Like our Galaxy? . . . I am just kidding.

[@Mernom]

@@idowhatiwantdowhatisaygoog2361 except that the perpetual motion appears even if you don't treat negative mass as a self replicating substance.

[@archenema6792]

Perpetual motion machines never know when to stop.

[@AlejandroBravo0]

I hope Matt is okay :(

[@paradisecinema8170]

What music/songs do you use? Are they available somewhere?

[@m_i_g_5108]

Sarude Dandstorm, bro. You can get on iTunes or Google Play Store

[@jwb52z9]

The principle of negative pressure's effect is also used in medicine as a way to heal wounds because it has that odd effect on tissue as well.

[@soptereancosmin1041]

I just like that gas monster to the right of Mat waiting to take a big bite out of him. Also always wondered if dark energy could be a property of dark mass.

[@kyliemieko]

Can you please add captions

[@paulblasiman1818]

+

[@taylorbrewing]

Yes please

[@Ninjaznexx]

Dang it, I was doing captions for the first 2 minutes when Space Times themselves suddenly uploaded captions for the whole video :(

[@MegaFonebone]

Here are the captions for the whole video: “No."

[@cheekyboyz8121]

What suggests that there will be a "big crunch"? I always thought that the second law of thermodynamics suggested that the universe will end in a "heat death", or an expansion of the universe so extensive that all matter will be separated so evenly and infinitesimally distant?

[@Prometheus2508]

It does, unless something outside of space, or potentially from space itself, changes. 2LoTD largely dictates what will happen within a closed system, the closed system of what's in the universe. If the cosmological constant was dynamic, it could reverse the apparent infinite expansion.

[@filipsperl]

there was a Space Time video about changing constants that features the cosmological one i think

[@stefanb6539]

I guess the big crunch is just another name for the heat death variant. Just a more fitting one in a diagram, that already features a big bang.

[@troyhenry6111]

No it doesnt say the only way the universe will "die" is heat death. If the universe reverses lambda, then it will shrink again.

[@borttorbbq2556]

Basically think of a super Nova that makes a black hole that pulls all of it's matter back into itself

[@Yaroslav_Tselovanskyi]

Me: - wtf? Negative Mass particles: *Continuously popping into existence between the galaxies*

[@ChrisWalshZX]

"Next Week" is pretty optimistic if you're stuck at an Event Horizon! I anticipated the nod to Hoyle's Steady State theorem as soon as Matt said about negative energy density remaining constant during expansion of the universe yay!

[@Billmao]

Happy new year! welcome back!

[@lithostheory]

Anti-unicorns!!

[@tomf3150]

Mirror-universe unicorns....now with goatees

[@neoh524]

They don't exist

[@MCsCreations]

The universe sounds too dark for my taste.

[@archenema6792]

Stop tasting my universe. Last warning.

[@MCsCreations]

@@archenema6792 😮

[@Lexivor]

Good thing the dark universe was cancelled.

[@archenema6792]

@@Lexivor Do you mean the Lexx? The one with the hot German chick, or the one with the not-hot Canadian chick?

[@Lexivor]

@@archenema6792 I was referring to the planned cinematic universe based on the Universal Studio monsters. It was cancelled when the Mummy flopped in 2017.

[@nineball039]

Anti-unicorns?! How to politely ridicule another scientist's work. As always, thanks another great video Matt. You put a lot of time and effort into this channel and it shows.

[@austinglugla]

Read the paper a week ago, was expecting you to cover it considering it's potential implications. Also in the video on the limit of computation in the universe you did not talk about photon encoding!

[@franzschubert4480]

Dark energy = dark matter * (dark lightspeed)^2

[@GumbyTheGreen1]

"as more space comes into existence... the more dark energy you get" Wait, so new space and energy are always coming into existence? The universe's total energy is increasing, not conserved?

[@bxdanny]

Maybe the new energy somehow balances out the energy that is lost when light is red-shifted to lower frequencies and energies? It's hard to see how that would work, the lost EM energy would have to be constant for the gained dark energy to be constant, and it probably isn't, even on a large scale.

[@GumbyTheGreen1]

@@bxdanny Yeah, it's hard to see how those two things could be linked when they can act independently of each other. If things had happened slightly differently, the universe probably wouldn't have stars or light at all. I'm sure someone could explain to us why redshifting doesn't actually imply a reduction of total energy.

[@alienrenders]

In another video, he talks about how conservation of energy is a local phenomena. It doesn't hold true at cosmological scales. I think it was something about the constant density theory. As the universe expands, it creates more dark energy to compensate for the extra space in order to keep the same density. I don't understand why it needs to keep the same density. I guess it's needed to keep in line with observations of the rate of expansion of the universe. How or what process would cause this to happen, I haven't seen an explanation of yet.

[@jeronym_noise]

It can be somehow linked to black holes? IDK

[@bretsheeley4034]

It's the issues with dark matter that make me wonder whether the universe is actually a closed system or not, like there's some equivalent to a low-pressure system outside of a balloon. ... Yeah, I have no idea what I'm talking about.

[@MrKafein]

Yeah, maybe our galaxy is stuck with other galaxies between giant balloons of invisible matter that makes up to 90% of the Universe. I don't know what I'm talking about either.

[@dalton6173]

Thought experiment, you have a Googleplex of magnets spaced apart far enough where they can not immediately connect yet their magnetic field is strong enough weakly pull on all other magnets... the magnets will instead of all clumping together or clumping into pockets will forever be "pushed/pulled apart" because there are more things acting on it to move away from its closest neighbors (with random exceptions where the paths intersect or where the attention is to powerful with a near by path.)

[@Sollace]

All the best wishes go out to Matt, who's currently stuck at an Event Horizon. 13:13 See you in a couple million years, Matt. Your videos have been Interstellar.

[@Vikash137]

It just seems to me that astrophysicists have no idea wth is going on so they're just guessing at literally any possible thing.

[@AlcyonEldara]

That's how science works, you know xD

[@filipsperl]

that's what's called doing science

[@Laff700]

I'm fairly certain this is the case. I will say that the new avenue of negative mass/energy seems promising. It needs more work though.

[@12201185234]

You have just described a hypothesis. Congrats!

[@AlcyonEldara]

@Mr.BigBoss7 and how do you know what tests will be done without créatif models ?

[@lordgarion514]

"Theory" Being a little generous?

[@SnlDrako]

"Lazy journalism" Duuude, if you'd see half the... uh... manure I see in the memestream media...

[@donotcare57656]

Good journalists are the rarest thing in the universe.

[@harishjain2612]

I found a paper by Anton Zeillinger, President of the Austrian Academy of Sciences titled "Effective Mass of Neutrons Diffracting in Crystals". There is an apparent negative mass along with positive mass neutron beam inside a crystal lattice deflection experiment. It is worth a look. Though this effect is only observed inside the crystal