What If Dark Energy is a New Quantum Field?
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- Опубликовано: 22 дек 2024
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What is Quintessence? Well we know that something is up with the way the universe is expanding - there’s some kind of anti-gravitational effect that’s causing the expansion to accelerate. We don’t know what it is - just that it competes against the inward-pulling effect of gravity. And it’s winning - it looks like the universe will expand forever, at an ever-increasing rate. We call this mysterious influence dark energy, but while we’ve talked a lot about how it behaves, we’ve never really explored what it is. So, what is dark energy, really?
One strong possibility is quintessence. Quintessence is a hypothetical form of dark energy, more precisely a scalar field. Watch the episode to learn more.
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A few of our eagle-eyed Space Time fans have noted that 3:48 what is labeled as Dark Matter and should be labeled as Dark Energy. They are all technically correct, the best kind of correct.
Futurama reference appreciated.
The video is also technically correct!
Since the grain of sand calculation is an order-of-magnitude calculation (since the mass of sand grains vary wildly), and because as stated in the video, the overall density of dark matter and dark energy is coincidentally within a few orders of magnitude, the typo is not *technically* wrong!!
When science shows decide to seriously delve into quintessence--Earth, Wind, Fire, Water, Dark Energy--I bow-out and unsubscribe.
It has been fun, but reality is over there, and I am going over there.
Stay safe! Enjoy stupidizing the planet! Don't worry about the horrific danger you are putting the future of humankind into!
Ciao!
@@ZeroOskul Did you actually watch the whole video? Or are you trolling?
@@AlbertaGeek Good News! I liked it too
This show has been on a roll for YEARS. Amazing that we get this level of content on such a regular basis.
Yeah, right? I just wish it never ends and it helps spawn more quality content programs. Big shout out to PBS
Fo real. It's watching science being scienced in realtime.
For FREE, nonetheless!! This channel challenges the adage that nothing of value is ever free 😝
I have remembered and after that learned so many many concepts, old and new, here. This show adds so much to RUclips, that they should recalibrate their algorithm with a variable like wisdomSpreading
wrrr
Matt and Space Time team: I'm not a scientist, I'm a music teacher. I don't fully understand most of what is discussed on this show; especially the math. But just because we don't fully understand something doesn't mean we can't be fascinated by it and appreciate it. I feel like a child listening to adults when I watch Space Time, and I mean that in good way. What a humbling and satisfying thing, to be able to even partially follow discussions concerning the farthest edges of humanity's understanding of the universe. Thank you, Space Time!
Great comment. You said how I feel, but I could not have explained it like that. I have no ability to do the math needed for physics, or to actually follow the specifics. But it is wildly interesting, and I feel like a toddler trying to comprehend how we even exist.
Great way to relay what alot of us probably feel.
Just the fact that you're watching these videos out of curiosity is a good thing. Learning new things is great.
Give yourself some credit, you have a more intimate understanding of time than how many people, friend?
Thats an amazingly insightful and introspective answer. I admire that. You recognize your ignorance and your inability to fully comprehend the matter but you're still mesmerized by the subject.
I'm not. physicist and am not an atheist I know you can't quantify God. But I had heard Infinity and Eternity is quantified by math and science , thanks to PBS space time for explaining in as close to layman's terms how thi was the case for the last 4 years of their many wonderful videos
I don't usually understand all of the content in these videos, but I've noticed that over time, if I go back and rewatch older ones, I understand a lot more than I did the first time I watched it. I'm subtly learning about physics while hardly noticing the change.
This show has caused me to become so immersed in astronomy and physics. Introduced me to new channels and ideas regarding different fields. At first I thought I'd never even grasp some of these ideas because they seemed like gibberish at first. As I kept up with the channel I found myself learning some of the theory in all of it. There's so much to learn for me and there always will be, but I'm grateful for PBS Spacetime for intriducing me this. After i graduate in engineering I plan to study more in the field of physics. Thank you.
Thanks for what? More theories that will never be DEMONSTRATED?? GRAVITY ITSELF HASN'T one IOTA of PRESENCE or SUBSTANCE of ITSELF to DIRECTLY DETECT, IDENTIFY, ISOLATE or HARNESS!! Acclaimed PHYSICIST Erik Verlinde ADMITS that GRAVITY ITSELF is FAKE/INTANGIBLE!! ruclips.net/video/rRJaMHi_--w/видео.html
yes and I admire your perseverance. On the other hand I found the youtube channel SCIENCECLIC ENGLISH which explains things very simply with fascinating and realistic videos in a way that anybody will understand the concepts the 1st time.
Don't work for PBS Spacetime, but as a trained physicist comments like these absolutely warm my heart ❤
Please never give up comment responses!!
So few people do it anymore and it really proves your integrity and willingness to change when shown your wrong.
So proud of u guys keep it up!!
I never thought videos so difficult to understand could be so addictive 😂
Edit: Now that this is top comment I should say that I actually think this is a really fascinating way to learn. Even if it sounds like gibberish at first, if you watch enough of these videos, patterns emerge and even high-level concepts begin to make sense in relation to one another.
I just nod and take notes. Definitely don't sit here with a bowl and a blank stare...
@@thesundrinker I too feel the need to take notes.
I tend to watch a big chunk of these at a time when I find myself in the right frame of mind and can shut out some discomforts or other distractions. :)
This! It's basically mind tickles, sometimes it hits hard though.
They're the best. You get to watch them multiple times and a new thing makes sense each time.
I saw a physisict saying "After 30 years of thorough research and studying of Dark energy we have come so far that we have a name for it."😀
Still an improvement over electricity. The ancient Greeks knew about static electricity like all humans, but it took thousands of years (!) to make any inroads there.
But I digress....
It's progress. I remember when Dark Energy was all farmland.
and always I hear about dark energy and antimatter it still sounds like some semi-bad science fantasy term xD
@@nosuchthing8 The field made major mistakes in naming things and the poor naming directs more funding into some areas over others.
Dark Energy definition is anything that solves the "increasing exapansion rate of the universe" and this includes answers it's not expanding there is no enery required for the answer.
Dark Matter is any answer to the gravitation anomilies observed matter is not required.
I would've called it, 'This Thing That Happens Maybe'
Dr. O’Dowd, I’m sure I speak for many viewers when I say that we very much appreciate your talks. Your time and effort serve to illuminate many important subjects that we would otherwise remain oblivious to.
I'm super hyped for this video! I'm writing my final degree project on the thermodynamics of dark energy!!
I'll apply the thermodynamic approach to the equation of state and see how do the different scenarios hold up!
It's so nice to see the topic explained by Matt, and so satisfying to know that I got it right through the papers ...
THANK YOU SO MUCH PBS SPACE TIME
What are you studying? I'm about to dive into the world of physics and even though I love and excel in math, I'm sooo incredibly afraid of failing my classes lol
I’m old enough to remember being taught space was either going to collapse back on itself, expand to a point but never get there, or keep expanding in size forever, more and more slowly but for sure one of those three. To learn space is actually accelerating came as a shock to everyone, it makes sense to me something like quintessence could actually be true as well. Reality is stranger than we think, even if we take that into account.
Note it appears to be expanding and the expanding accelerating as noted by one on early talk on subject it could instead be a field that obsorbs some of the energy from light that exists in intergalactic space only. In this case the red shift would be from energy loss not Doppler effects.
Yes, but is space gay enough to get funding?
I'm going with r = 1/t, rate of expansion is 1 / age of the universe. Objects beyond a certain distance will accelerate due to their distance increasing faster than the expansion slows down, but that expansion rate will decrease logarithmically.
Im not old enough, but really just had old science books for young readers back in my childhood. So i had the same idea of uncertainty back then
Hugh Mongus what?
HUGH MONGUS WHAT?!
This was one of the more mind-blowing videos you've done. I had to watch chunks over and over -- it felt like I was putting together a really tricky but amazing puzzle in my brain.
Welcome to time field Theory....Everything he is talking about in this video is basically where I started. The answer I have come to after working the equations and 10 years of thought experiments + existing experiments is this: 13:04 "the only way to get Omega less than negative 1 is for the kinetic energy of the field to be negative. is there a process in the universe that causes this? yes!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@@hyperduality2838 based
@@hyperduality2838 Yes, absolutely. I love your profile picture. Do you believe in aliens?
@@hyperduality2838 What is “God”?
You know it's gonna be good when Matt looks tired. Your hard work is much appreciated. Thoroughly enjoyed this new (to me) perspective. Does it make sense to think of scalar fields as constant accelerations of values in other fields? In other words: We measure a constantly accelerating force, could such a force be always explained by a new field?
What if time loops around and to travel back in time is to go fare enough forward..but then your still going forward in time
@@osmosisjones4912 straitgh paths, make curves
@@osmosisjones4912 Technically if the universe is cyclic then going far enough into the future you'd eventually stumble upon a perfect replica of our universe with everything being the same, except then you could go to year 1367 instead.
You would, in a way, go back in time and you would (probably) not cause any paradoxes
I once considered the idea of the universe having a higher-dimensional toroidal shape constantly turning in upon itself creating a sort of cycle. At our mere 3-4 dimensions we can’t perceive this higher-dimensional shape, being trapped to the curvature of spacetime. Instead we just look so far into the future I think we end up looking in the past. This would also explain expansion and contraction, aka Big Bang and Big Crunch. As our ‘region’ of the universe reaches the outside of the ‘donut’ toroid, it stops expanding and begins contracting again.
But I’m just an amateur layman. I’m good at math and physics, but my ability to put thought into words is pretty poor. As you can tell.
Big head is stoned out of his mind.
PBS Space Time is by far my favorite physics show. Looking forward to the next installment... Fantastic job done by the presenter Matt ..... the mathematics is beyond me at the moment but I love the fact that PBSST isn't afraid to explore some of this with its audience.
If even a grain of sand can overcome dark energy influence, does it mean that the expansion might be vastly uneven? Especialy in regions of the universe rich in megastructures, like the great attactor, or very empty, like the great void?
expansion simply does not happen in places where matter/radiation dominate
Thank you Matt and PBS for another one. PBS Spacetime is among my most cherished productions of my life so far.
Truly makes me happy to watch and rewatch everything and try to learn.
Straight up this.
It's wild that something so integral to the universe can be so hidden from us.
It's not hidden, look up Ken Wheeler the man has been going on about it for ages. It's just that he purposefully uses terminology the modern particle physics have deemed as "heretical".
You mean, like God?
@Seven Inches of Throbbing Pink Jesus - Never respond to me again.
Just think how many things that are integral to the earth were hidden from ancient humans.
@@rubiks6 And Baphomet said onto the people: "let there be plagues and locust, cocksuckers and taint lickers. Let the skies fall down and drench the innocent in the blood of the scarified; for that is what I command of my faithful."
Let's all grab hands and chant together now.
Love these videos. I think they're pitched at a decent level, really pushing my level of understanding.
I concur.
I, too, am in accordance.
I can't stand them. I don't want to make a gigantic effort to follow such a fascinating subject. So, I found the youtube channel SCIENCECLIC ENGLISH which explains things very simply with fascinating and realistic videos in a way that anybody will understand the concepts the 1st time.
your explainers are really fine on the details you choose to explain in each video. im not a physicist and im beginning to predict the missing knowledge i have on these subjects. asking the right questions and sometimes im even onto something.
I definitely shouldn't watch this while drunk. I played 3 times and still am confused but yet love it. I'll watch again tomorrow when I'm sober. Right now the only dark energy I'm feeling is the whiskey in my gut. Much love PBS Space Time. I've learned so much from this channel!
I love you explaining these very difficult concepts without dumbing it down. Thanks!
That’s so awesome how you likened the theory of a dark energy field added to the other 4 forces to the five elements. Thank you Matt
Wow! I can only imagine all the hard work that goes into making these episodes! Incredible! Thank you Matt!
Such amazing descriptions (and jokes) of current discussions of cosmology, I'm always learning so much on this channel. Glad the patreon support helps too! So worth it!
Watching Matt and Space Time reminds me of being a kid and watching Jack Horkheimer and his show Star Gazers. Props to PBS for keeping up for so long 😁
Imagining the force of dark energy as a field finally helps me understand how space isn't expanding everywhere, with the galaxies just flowing back together. Does that mean the angle between galaxies change, when there's more void on one side that the other? And is quintessence the same as the inflaton field?
Serious consideration, is it possible that the quintessential and gravitational fields, if the exist, might be a single unified field that excites omega to a positive value in the presence of mass carrying particles of other fields? They both seem to work on such a strangely similar mechanism, one constricting space time while the other causes its expansion when unchecked.
gravitational field is not a scalar one, hard to combine them
So the question essentially is what's the difference between gravity and quintessence or dark energy. (apart from the obviously inverted sign)
That's what I was thinking, that dark energy might just be a particle, thus some kind of matter, that just happens to have a "negative gravitational charge" rather than a "positive gravitational charge".
Tangential question:
Space is expanding, in opposition to gravity. Space is actually spacetime. Does this mean Time, too, is expanding, and is this where our experience of time comes from? Would that mean the field described in this video would be a field of time?
It's just the spatial part of the metric that "expands" - according to FLRW
EDIT: I added more info below in this comment section
@@SitremChannel Cool, thanks!!
Physicists say time is constant but this seems to remove it from the concept of Space/Time. I think time is the most misunderstood of concepts in physics
Here is how I see it, of course time is expanding. If time started with the big bang, then every moment that passes is the expansion of all time. If your relative measurement of time is how long it takes for the earth to orbit the sun, then time has expanded 14. Whatever billion times the "size" that it started at.
@@freefall9832 On what basis do you think time is the most misunderstood concept in physics? Where is your data?
I’m not gonna lie, I go out of my way to not watch any corporate or “big group content”. I only watch those who started from the bottom. PBS is the exception. Never thought
WOO HOO!!! I finally made it! I have finally watched every video from this channel! PBS Spacetime I cannot thank you enough for everything you do. You have inspired me to continue this journey and I can't thank you enough. - Salutes using two fingers in front of eye*
What if our cosmological constant is really just a severely dampened version of whatever causes cosmic inflation? The same force is driving our expansion, but something is heavily interfering with it to the point that it's become extremely weak by comparison? And what could that nearly-cancelling force be?
Meh it's really obvious everyone is over thinking it. A simpler explanation exists.
Have had some thoughts in the same vein, like almost an inertia (or viscosity?) due to the coupling of fields. Nice to stretch the ol' brain a bit 👍
@@hyperduality2838 alright yoda that`s too much internet for you today
incredible friend, I also reached the same line, if you saw in the video there is a point where they mention a k-essence model.
apparently it is relating the quantum fields responsible for radiation and matter inversely with dark energy.
dark energy according to them, increases as matter is diluted by expansion.
remember that there is a problem with the cosmological constant, when measuring it experimentally the result is a very small value, but if it is calculated theoretically, the contribution of all the quantum fields that exist is taken into account and this gives a value of one order of 10^120. that energy could be practically the one that the inflaton field had to start the inflation.
After that, matter appeared, and in the video they mention that it seems that the quantum fields of matter are generating a kind of cancellation in this quintessential field (lower energy inflation).
The question is, if space continues to expand, will it reach a point where there is absolutely no energy to generate these cancellations and all quantum fields are free to contribute their energy, will an inflationary process originate again? the beginning universe of the absolute vacuum where the quantum fields have the freedom to act? we would no longer need a singularity.
Question - Since expansion increases over time the closer galaxies are expanding faster than far ones that are older? So the farther away we look the less expansion there is because we are looking at older galaxies and the expansion is accelerating? It's hard to find a simple explanation of the observation without interpretation.
It's the other way around. The farthest galaxies are moving away from us the fastest. Hubble's Law.
@MaxBrix Realize that what we see when we see those older, more distant galaxies receding isn't proper motion of those galaxies through space. It's all of the space between there and here which has expanded between now back to when their light we're now seeing was emitted. The farther you see, the longer ago whatever you're seeing was, and there is more intervening space there which has expanded, and it has had more time to do so.
As it is known that particles can pop in and out of existence as the vacuum of space is filled with potential/energy. What would the effect on space time be if trillions of particles are popping in and out of existence between the galaxies? Could they add weight (each briefly but overall massively) to the universe as each individual particle is invisible? The pressure of each 'pop' outweighing the gravity of each particle popped.
I had thought the net amount of transient mass needed at any given moment to account for dark matter in this way is out of the question because it would be observable in ways dark matter isn't, and doesn't fit with dark energy, but I think the video suggests that something like this somehow acts like a gravitational attractor at short ranges for omega = 1, but as a negative gravity pressure at long ranges, which sounds at least as convoluted as MOND to me, but I'm no cosmologist. I need to watch this again.
From when I first heard of vacuum energy powered by uncertainty and very quickly realized that Space-Time might be like ginger-ale bubbles erupting, pushing against each other, and popping, or what is now theorized as 'foamy'.
It has been 24 years since I had this insight and it is nice to see physics coming around to a lot of my insight. I am not a physicist, though I understand a lot of what is theorized here and elsewhere, and I am certainly no mathematician and there is no way I could describe my insight with hard calculations. I just heard an intriguing finding and my imagination ran it through a large number of what-if trains of thought. Out came what is very much the idea of SpaceTime foam.
Call it coincidence, inspiration or just plain weird, it is intriguing.
Keep up the good work and you may inspire others much more capable than I to greater insight of this universe we live in.
Thank you so much for creating and running this channel so well for the last couple of years
Hey, I was just learning about dark energy....from your previous videos.
Love you Matt!!
So bruce willis really did save us all. Amazing. 20years later and the true fifth element is revealed. Love this channel
Wonderful episode, great graphics. These episodes that espouse on more modern thinking are great!
Good review. Being a longtime corksniffer and drinker of Jamieson and Tullamore I have recently tested alternatives and I would buy Teeling Small batch again. My impression for what its worth. Several sniffs later and I was impressed with the aroma. I interpreted, geranium, toffee apple, poplar, tomato and fig all being present. After a few swigs I was pleasently surprised at the very light bodied taste and the lingering intense spirit nature of the fluid. I missed the full body flavour of Tullamore or Jamiesons.
I always imagine the universe like a bowl of cherrios and milk being poured out onto a table. Each cheerio is like a galaxy and the milk is like the space between. It expands rapidly at first because of the high density when it first hits the table, then it slows down but continues to expand in all directions. As the cherrios get far enough apart to not stick to each other they accelerate away from each other. Since the cherrios have mass, they have to be accelerated to the speed of the expanding milk. They lag behind at first but eventually are carried along with it. The milk may not actually still be accelerating, but the stuff in it appears to accelerate as it matches its speed. The question remains, what is beyond the edge of the milk as it races across the table. It could be a new nothing that does not even have what we know of as empty space. It could have an edge, where it's surface tension prevents it from expanding further. It may thin out forever.
Yessss...I've been waiting for this cheerio/milk theory. Can it be almond milk though?
@@tombsandtemples I vote oat milk
You're all wrong... milk of magnesia.
I also like this Cheerio-Milk analogy but it needs some adjustments. As is, it implies that there is a milk flow; from a milk source to the outer edges. If I am not mistaken, this is not the case. It's more like that the milk is "being conjured/magically appearing" from every point inside the bowl's volume, as if every point (plank voxel) was a milk source, while the bowl expands accordingly to contain the ever increasing milk of the cheerio-milk soup; the Cheerio-Infinite-Conjuring-Milk-Source analogy.
@@JamesSarantidis obviously, being an analogy it isn't perfect. It does align to the way the universe seems to expand. The matter isn't expanding but the space between is. It seems to align to the rapid expansion early on. In this analogy the bowl no longer exists. The universe poured out into a new void where it could expand freely.
The universe may be made of 2 things, space and not space. Space seems to be some kind of fluidic energy field that extends as far as we know. Not space could be the basis of all matter. If you consider that matter and energy are interchangeable at some level, they have to be made of the same fundamental stuff. If energy is made of compression waves in the fabric of space, matter seems to be made of bubbles or voids in the fabric of space. Collapsing one of those voids, leaves nothing but compression waves behind. The right combination of waves can spontaneously generate a void. This is how matter and energy can be converted into each other. This means that space has some kind of surface tension that corresponds to the plank constant.
It also explains why wave travel through space at a constant rate, but matter cannot be moved at that speed. To move a hole through a fluid, it opens up new fluid at the leading edge, but closes the same amount behind it. The total net energy difference is 0. To accelerate requires opening space at the leading edge faster than it closes behind. This actually creates matter by making the void larger. The closer you get to the wave propagation speed of the universe, the more mass is created during acceleration. This seems to correspond to the properties of matter and the constraints of physics on matter and energy.
I'm still trying to grapple with the idea of Dark Energy only expanding space outside of gravitationaly effected areas of the unvierse, but with this video I think I managed to finally properly internalise it. It is so weak, that it can't overcome any other forces in any meaningful way, since all the other forces balance/cancel eachother out at such a magnitude, that there is no affection from it to any defined states; even if it "changes" something, that level of "change" doesn't actually CHANGE anything.
If time ticked slower at the beginning of the universe, similar to when you get close to a black hole, could this explain the red shift?
No, red shift is something more similar to a result of light falling into FTL. Not necessarily that it does, but that's a better way of explaining the red shift phenomenon than the actual detailed explanation of what red shift is.
@Seven Inches of Throbbing Pink Jesus That's only related to the speed of recording memories, which is entirely hormone dependant.
@Seven Inches of Throbbing Pink Jesus If you are 6 years old. 3 years ago is half of your life. If you are 80, 3 years ago is a much smaller portion of your life.
@Seven Inches of Throbbing Pink Jesus Look into it yourself before refuting it as a possibility. This is the internet, after all.
@Seven Inches of Throbbing Pink Jesus should I trust redditor and RUclips comment anecdotes? Or the neuroscientists studying the functioning of the brain and how it processes and correlates time, memory, and consciousness? Hmmmm. You don't have to trust neuroscience at face value, but you should probably consider the proposition that something strange in your perceived experience has a physiological basis... over, say, Time Cube-wannabe internet commenters discussing how focusing on a cup of water caused the cosmic rift to universe split. Or how the spelling of Froot Loop cereal demonstrates that we live in a simulation.
One of the aforementioned body of knowledge is science and the other is... something else entirely
every episode is wow, i’m so stupidly happy when i see a new one is available and i’m sad when i ear the final ‘spacetime’.
Quintessence is a mind blowing concept!
I loved season 4 of Avatar: the last Airbender when Aang traveled to the Quintessence Commonwealth to learn quintessence bending, make zany friends, and save the commonwealth.
If a simulation is accurate enough is it really a recreation
Dark Energy is like the long term Scaffolding of Universe’s structure
Lmfaooooo, it's called the Aether, and perhaps dark energy is the signature for it we've been looking this whole time ;) space itself is nothing but a shadow, in the Aether. Human beings with our monkey brains have reified concepts like "time" and "space" to mean real things, but they aren't real - they're simply a form of measurement of change. Same like how a shadow isn't a real thing but it's what something else casts, 3D space itself as we perceive it is simply a "shadow" cast in the ether by a divergent magnetic field ;)))))
@@Positive_Tea Doesn't entanglement prove that there is something there?
That’d mean the universe has negative curvature, which it doesn’t have. It’s flat… like the Earth. Lol. But for real, it’s a quantum effect from the low pressure and cold temps of the hydrogen and helium in the voids.
AHAHAHA
@@maeton-gaming it's literally called spacetime, not the eeeeEaEtHeR.
is there anything called dark expansion?
I figure it would either be similar to what happens to the water before a tsunami, pulling everything behind during the start of inflationary expansion. Considering it's in space, there wouldn't be any build up pressure stopping it from expanding. Or would it be more like a large truck passing by a smaller vehicle creating a "lower" pressure zone creating a larger vacuum behind? The original big bang blast being the large truck.🤷🏾♂ idk I get confused by the idea.
When it comes to Quintessence couldn't that be a layer of space where time hasn't yet been formed? If outside the cosmic universe there is a state where nothing has changed is that the same as time also not being present (time here being a state of changed?) The idea is that it would make space prior to the big bang a "timeless state" then the big bang blast being the force creating "dark expansion". Essentially the force of change that created time/change of the cosmic universe.
Regardless as far as I can understand there seems to be 3 main forces driving.
1. the state prior to time/the dark expansion, also being known as ambient universe pressure.
2. the force of the big bang creating a more positive pressure (expanding into a unlimited vast of ambient universe pressure) * possibly creating another variable of pressure on the receiving side "tiny residual" .
3. The vacuum/gravity created from inside the expansion of the big bang pulling things outward.
Either way I'm not sure what could be found when searching for evidence of an anti-gradational effect outside a quintessence field .
I always regret watching these videos after drinking but forget to rewatch them when sober
I’ve always imagined the universe breathing, periods of expansion and contraction like a system. Cool to hear about quintessence and maybe that theory being explored theoretically. Thanks for your work!
probably not, though.
6:55 "it could be that our assumed cosmology is wrong". All the people who believe we know exactly how the universe works are just unaware of how much there is left to learn.
Exactly! We can reason with what we know, but we should still be searching for what we are oblivious to.
That's a very specific statement for something so unknown...
@@unvergebeneid right! It’s paradoxical. It’s like saying: Let’s do what we can’t
but the "all the people" you refer to are not the cosmologists. it is funny how this reproach is always hurled at mainstream science when it is the maverick crackpots who really are cocksure
@@_Donovan I wouldn't call it paradoxical. I'd call it mysticism.
Gravity's influence on expansion is limited to the speed of light, but dark energy's expansion is NOT limited to the speed of light. Therefore, dark energy wins.
Dark matter , dark matter and the big bang have all been disproven by JWST discoveries. Why are we still committed to this delusio
@@becbarry9866 We're not talking about Dark Matter. Pay attention, fool.
@@Bult He said nothing about Dark Matter.
@@planexshifter He deleted his comment, Karen. Pay attention, fool.
Question:
If it's found that Quintessence does evolve over time, wouldn't it mean that our estimates for the age of the universe are wrong?
Yes
_Estimates_ are wrong by definition. The real question is, how far could such evolution have thrown off our estimates? For example, when someone says they are "29 years old" they aren't actually 29 years old; they are 29, some months, some days, some hours, minutes, and seconds old. But, for practical purposes, differences of hours or less are essentially always considered negligible; they are only used for full Zodiac charts. Differences of days are *occasionally* used, but almost always negligible; same for months. Thus, your "age" is an estimate of how long ago your birthday was. It's wrong, but it's close enough. Likewise, the "age" of the universe is an estimate of how long ago *its* birthday was. So, if the nature of Dark Energy is throwing off our estimates, is it the equivalent of throwing off a person's age by minutes or hours? Or by days or months? Years? _Decades?_
Yes
@@omargoodman2999 wow thanks a lot einstein we all understand that an estimate isn’t exact 🙄
@@kashu7691 Let me explain it more simply for you since you seem to have not understood; maybe you forgot to read past the first sentence. Of course it would mean the estimates are wrong, that was already a given. But is the new information enough to make a significant difference and we need to re-work the estimates into new, still wrong, but less wrong, ones? Or is the difference negligible enough that the original estimates we had are still not so wrong that they can no longer be relied on? At such a preliminary stage of research, we just don't have enough information to yield a clear "yes" or "no" for practical purposes.
An old adage still applies to this case: The absence of evidence is not evidence of an absence. Just because we have not found it, does not mean it is not there; we could just be looking in the wrong places or the wrong way. That could be the case for quintessence particles.
Simulation theories are cool, Ive always enjoyed the idea of spacetime/dark energy being the medium in which things exist but effects relating to our biological experiences like perception like sight, when our eyeball interacts with a photon translated by the brain and the observer effect, all different potential realities/outcomes we can observe like the double slit experiment happening to consciousness all the time. Not just the physical, but virtual and spooky lol i enjoy thinking that reality could be more magical
If Dark Energy is another field, then could that field be manipulated in such a way that it could generate a FTL warp drive? That is, if you transfer Quintessence from one point in space to another point of space, creating a vacuum of Quintessence on one side & a surplus on the other, then could an object positioned in-between these two points be propelled at faster than lightspeed as the two sides return themselves to a state of Quintessence equilibrium?
That sounds a lot like an Alcubierre drive. And yes, in principle, IF we could manipulate it, we could distort space-time so we could achieve FTL travel.
Something being a field does not mean we can manipulate it. That is a big leap in logic in your question.
Something being a field does not mean we can manipulate it. That is a big leap in logic in your question.
@@angelmendez-rivera351 FTL drives are already a topic that pushes scientific knowledge to the fringes of theory. Right now, FTLs are just as uncertainly probable as there being a 5th fundamental field, so I don't think It's that big of a leap in logic to ask if there could be a theoretical FTL application. Since I can't understand the math, I won't know if I don't ask.
@@nachoijp I agree with whats already been said about manipulation of fields. Dark matter however is a different story and uncovering its reality could unlock a world of possibilites
I barely got through the undergraduate physics program at university so if I goof up the observation, mea culpa. At the beginning of the video where you first began talking about the process that leads to the creation of, and subsequent further creation of more dark energy, sounded so much like recursion. We were always warned in Comp Sci to tread lightly if we want to go there. I can see at a kind of intuitive level, that dark energy might be a problem ... lol
I love these videos! Go PBS Space Time! Love you all!
I can really appreciate how mathemeticians and physicists get pet theories now. The fact Quintessence fits so well with observations, it seems so beautiful.
Science is so freaking cool.
Dark energy has been the most complicated subject for me to understand… it doesn’t work like anything else
It doesn't work because it doesn't even exist.
@@lemmetellusum4884 it's just a theory but it doesn't mean you're correct either...you need to explain how it doesn't exist by your own theory..even vacuum space has quantum field with 0 energy
@@BenjaminMilekowsky My theory is simple, if you cannot prove your theory it just doesn't exist. If you claim you have any valid explanation that these stuff really exist then I might come up with my explanation. Until then it's just beating a dead horse.
@@lemmetellusum4884
what !!? Sorry are you bl*nd ?
So what did you see the massive blackness in the night sky..eventho it's just a theory and we named dark energy dark matter or whatever, but it means exist because we can clearly see it..maybe we were wrong about the theory or to name it but once more it is something there
@@BenjaminMilekowsky I suggest you to watch Rupert Sheldrake's conference talk on EU (Electric universe) from 2013 called "Science set free". You might find the reason why this whole "dogmatic belief system" called mainstream science is so confusing and nonsensical. It's not a flat earth theory nor some crazy conspiracy theory made up by theoretic physicists who just couldn't stop worshiping Einstein and his fantasyland. It is the new theory that terrifies mainstream scientists because it makes more sense than this whole big bang, black holes, dark matter, quantum mumbo jumbo stuff. It is called the Electric universe theory which was later developed by David Talbot and Wallace Thornhill. Do a little bit of research on it with an open mind ofc and I guarantee your whole perspective will shift into another level of thinking instead of just blindly believing and accepting whatever NASA spits out.
My favorite Theory is that Dark Energy is just the natural "unbend" state of SpaceTime, taking back its natural "volume", when not smooshed together into tight Blobs by Matter. Looking to us like Spacetime is expanding, but its just spreading out "without ripples & folds"!
Know Sci Man Dan?
I think it has something to do with higher dimensions and what is outside of the known universe 🤔
Could space itself be dark energy? Space seems to exhibit the same properties, and would maybe explain inflation (if space creates itself, then we should expect exponential expansion, right?)?
Yes, that is the standard "cosmological constant" explanation talked about in the video. If space itself had an energy, it would act just like the dark energy we see.
That’s the idea behind a non zero vacuum energy. There’s a video on this as well
Kudos to you for explaining cutting edge theoretical physics in a way that an interested layman can appreciate
This is the first PBS space time I felt like I understood. I paused, rewound the video multiple times, repeated what he said out loud to help myself process. It was an extremely rewarding experience.
From my understanding, the quantum field explanation, means that dark energy is tied to a fundemental force of reality rather than random particles appearing in a vaccum. The quintessence field, means that dark matter responds to the state of the universe, and changes over time. This also is the flaw and benifit of the theory, is that it's very flexible yet conversely hard to prove due to said flexiblity.
Also, in this theory, the laws of relativity would have to be broken for the big rip to occur. (on a side note, this theory seem far more optimistic on the fate of the universe, I can only hope in case I live another billion years)
I still insist Dark Energy is the measured difference between actual expansion rate of the Universe, and what we can locally measure. The worst prediction of QM is probably right, and if you do that safe assumption, you can combine it slightly with GR to give rise to relative expansion rates, which we observe as gravity, Dark Matter and Dark Energy. It fits neatly into Eternal Inflation as well, which makes it sort of an implicated evidence for EI, which solves a whole lot of other problems.
I can't do the math tho.
> The worst prediction of QM is probably right
It's can't be, we would see an extremely rapid expansion it that case. We see a very slow one instead.
Couldn't dark energy just be a result of 4D spacetime? Like when you have a 3D sphere and go through it slice by slice it would look like a circle that is expanding first and contracting later, with a cone it would just be expanding. So if time is just not linear the universes expansion could just be the shape of time, right?
I'm not following. If the "time" dimension of space-time is an object, why does space accelerate outwards rather than slow down (I'm thinking the shape of a sphere)? If the "shape" of this 4D object passing through our locality of the multiverse - giving dimension to the dark and standard matter here - is a flared out horn shape passing by at linear speed, how could we differentiate that from a normal conical object accelerating through our universe, such as an object accelerates towards a gravitational influence? There would be practically no difference. What we observe - the accelerating galaxies moving away from us in all directions - could match either one of those 4D descriptions, because we can assume that an object in the multiverse that can move linearly may also have momentum, which affects other 4D objects.
The universe is probably a 4D hypersphere. Time is probably just a 4th dimension (direction) of space.
@domninin You seem to be thinking of time still being distinct from the "4th dimension" of spacetime. Firstly in General relativity (and apparently reality) there is not a universal "now" that eveyone agrees about, so your now-slice through the 4D spacetime isn't a single flat plain, or even a wriggly one.
But more importantly, the quantum field equations (and relativity) are already 4D state equations. If there were a simple pattern like that of the 4D sphere it would already have fallen out of the maths (to the disappointment of theoretical physicists everywhere) . However, instead they are having to use models that have too many parameters in the hope that experiment can limit the ranges of most of those to values that are related to existing universal constants (or maybe one more -- Omega?). If a relationship is found between the different constants then they can be eliminated by substitution, hopefully resulting in a nicer set of state equations.
Come on, everyone knows the fifth element is Leeloo...
These videos make me want to run out to my local university and pick up a degree in quantum physics but unfortunately I don't have the time needed right now to do that -- so I'll just have to continue watching these videos like a young dog that slightly tilts his head sideways as his owner says, "who's a good boy? You're a good boy!"
I don't know what's better--the end of the work week, or new episode of Space Time?!
When I was a kid there were only 2 planets: the moon, and the sun. Crazy to see just how far physics has come in such a short time.
you must be thousands of years old
Haha dude I almost drowned ...
@@thedeemon Yeah, the man's got to be at least 300.
@@Eagle3302PL 5000 more like...
When have the 7 classical planets not been known since ancient societies (up to saturn plus sun and moon)
Isn’t it the most likely thing, out of things that we know about?
If dark energy is anything of the kind that science knows of, wouldn’t quantum field be the most likely candidate?
Everything is a field. Everything is particles. Everything is waves.
There is no “quantum field”, but there are many quantum fields for each type of wave and particle. But perhaps you meant it as a generality, in which case I’d agree that it is a superfluid-conducting effect of the low pressure and temps on the hydrogen and helium in the voids.
What's simpler, adding an entirely new quantum field or just saying the field of space time which we know has to be quantum has energy?
@@ObjectsInMotion Ockham’s razor applies, mainly, to human conundrums, not the universe. All things are not equal out there…
Why assume that in just a little over 100 years we have discovered all the components of the universe?
You guys made another video on cosmic strings i saw recently, and it gave me an idea. Cosmic strings are areas of high energy vacuum the same high energy vacuum that was the norm in the early universe when expansion was much faster. You mentioned these strings likely pinch off and create loops which get smaller and smaller. If the entire universe was full of these microscopic string loops that were constantly splitting/self replicating, and the high energy vacuum inside them was creating space and expelling it from the strings it would act basically exactly like the dark energy expansion we observe. Since if they are creating space then being a loop theyd create internal space causing them to grow then split again. Replicating like cells. Theyd be really small and super spread out too so very hard to detect, and would explain why we havent found them yet.
Time travel? Did you say time travel Professor? well... It's good to know that J Campbell It's involved here (theoretically _ What Can Possible Go Wrong?) very appreciatted science class, as always, big thank you to you, the crew and PBS
MY MIND JUST EXPLODED. thanks to you I understand most of this.
Hey Matt! Awesome episode, I'm going to have to watch it again, not just because it all went over my head - but because I love the music so much! Is there a place I can find your background music?
My most favorite show on my phone! I wish To see a live stream one day!!!
Matt, question: Is the vacuum energy that's 10^120 too big dominated by contributions from fermionic fields, from bosonic fields, or is it about 50/50? Where would I find more information?
'We've been discussing every aspect of dark energy for years yet we never answered the most basic question. What is it?' LOL Man I love this channel even more.
So in an earlier episode you mentioned that when you split quark pairs apart they develop new quark partners. If acceleration eventually gets to the point where it's pulling the quarks apart really quickly, do you suddenly get a massive amount of matter? Like if the universe gets to expanding at the speed of light, that expansion energy would get absorbed by the creation of matter. That matter would be flying apart at close to light speed and be suddenly appearing everywhere at once. Suddenly you would have an energetic hot soup and a ton of new matter creating gravity and slowing down expansion even more. Big rip could lead to big bang. Universe infinitely recycling itself.
That is a very good question, I'd love to know the answer
This channel is absolutely amazing
I'm supporting you at the big bang level in my heart 😄
14:17 Subtle Return of the Jedi reference, love it.
love your videos. really enjoy listening to you.
I love this channel. I've been binging watching your videos all day long.
I love how these segments just get progressively more and more layered in complication when at from the beginning you think you might have a toe hold then 3 mins later your toes have curled up beyond your knees in confusion. A sort of..I can still make myself fell like I am smart just for the fact I have chosen to play this video I my life toe curling confusion
This episode was awesome. I've been waiting for this one for a while!
This live coverage is so awesome.
Storytelling at it's best! Has Dark Energy monetized itself with great ads yet?
Nice video, as always!
Quick note: At 8:27 you say that Quintessence was proposed in 1998. It was actually introduced already in 1988 by Wetterich, and Ratra and Peebles :D
This videos are going to be interesting when our understanding of the universe changes. Imagine whole documentaries given on the Thompson atomic model.
My newest personal theory is that matter behaves randomly until there is a certain mass, then it starts to follow rigid rules.
I could never hope to prove that, and I certainly can't do the math for it,
but it does fit in my brain better than most of the other ideas I see and hear, especially these days.
Whenever I see such tutorials I find myself pondering absurd questions. Probably because I don''t fully comprehend the Physics under discussion (it's not my field & my maths skills are woefully inadequate), but I'd like to think that looking at things from a different perspective can give some insights into what's going on.
That said:
• What would the expected characteristics of a *Quintessence Particle* be?
• Would it be like *Neutrinos* in how it interacts with *Baryonic Matter..?*
• Would it be expected to be massive..?
• Or even more radically, could it have (in effect) *Negative Mass..?*
• Or would fixed characteristics even make sense in this context, as their values continue to change (over time) in relation to other factors..?
~ ~ ~
• Does *Empty Space* - with virtual particles & anti-particles popping into existence from the quantum foam - have a *Temperature..?*
• As it expands (pushing more *Dark Energy* into a finite area), does this increase the *Temperature* or reduce it..?
*Thought experiment:*
① - Take *One Cubic Meter* of *Space* (a vacuum free of all other matter & energy) and (putting aside *Heisenberg* ⊚) measure how much _Change_ (virtual particles/anti-particles, movement of the quantum foam - whatever) occurs over one minute.
② - Now _Expand_ that *Space* so that *One cubic Meter* of original *Space* has now become *EIGHT Cubic Meters* of
*_E x p a n d e d S p a c e._*
③ - Extract *One Cubic Meter* from this newly *_Expanded Space,_* (so that you again have *One Cubic Meter* of *Space* to work with.)
④ - Measure how much _Change_ occurs over one minute in *One Cubic Meter* of *_Expanded Space._*
• How is the *_Expanded Space_* different from the original *Space..?*
• Is it _More_ or _Less_ Dyamic..?
• What other _Perameters_ / _Characteristics_ would change with the _Expansion_ of *Space..?*
⊚ - _'Just cause..._
10:51 - The problem with the Anthropic Principle is it doesn't actually explain anything useful. It doesn't explain why we exist in a time that allows us to exist, it only explains why we don't exist in a time that doesn't allow us to exist. We could've just as easily not existed _at all -- unless_ there's some aspect of the universe that (for lack of a better word) "compels" matter to organize into fractally-complex structures simply because it _can_ do so.
that really depends on what "explain" and "useful" could mean in this context. it has always struck me that explanation is not really a scientific concept at all. it is _neat_ whenever we can tie a bewildering variety of phenomena to a few simple posits, and to convey our enthusiasm we do say things like "now this can all be explained if we merely assume that..." but I actually don't think _explain_ means anything in itself in such a sentence, other than helping me make my students share my fascination with the subject. when somebody has done something bad and we ask them to "explain" themselves, we are asking for a different kind of explanation (unless there is a God, in which case we could ask God, as a person, to explain Himself and thus the way the universe is).
I share your misgivings about AP, by the way. It is unclear relative to which ontological commitment AP poses its "explanation" or at any rate, insights. Does it imagine a variety of different realities or universes with and then _obviously_ we can only happen to find ourselves in one in which we can (or even: be compelled to) exist at all?
Hi Matt, is the expansion of space within the universe linked in any way to the flow of time? Also, how does the expansion of the universe affect an observers view of time if at all? Thanks for all the great content.
Hey, I don't know if he will answer you but me I can, it's not often I come but i'm nice with physics.
Yes, but less you imagine. It's an affair of place to be clear.
The universe flow of time is incredibly fast but there's a shift per location, this means time goes slower with massive objects. The universe adds space ok but where the flow of time is moderated it's where we are or stars are.
It's like a train going to high speed, this time people in plays the motionless people, instead plays in the Relativity Train. It's just they try to make believe the passengers can slow down the train.... But the driver does not care, the train is on infinite rails.
Awesome vid Matt!
the writers had fun with this one, i appreciated the clever jokes and appreciate that they were kept few, perfect amount
Thank you for mentioning the importance of falsifiability toward the end of the video. The extreme flexibility of the quintessence scalar field, and its compatibility with seemingly any observation was setting off alarm bells for me. Ultimately, a theory that cannot be falsified is meaningless.
I thought of a possible quantum gravity equation and my brother told me to post it on a pbs spacetime video. Would like to see anyone's comments about this who know about biomechanics and physics.
The equation is W=(ma)d
I substituted gravity (F=ma) into the Work equation (W=Fd) in Biomechanics, which makes it a scalar (Work is a scalar in biomechanics)... I don't know if it being a scalar is significant but I thought it was... so gravity is measured in Work, (unit=joules).
In biomechanics, Work is the product of the force and displacement of an object. Thus we are measuring gravity not by its acceleration but by its total displacement. It's a simple equation yet measures gravity completely differently. It is a scalar but movement is still happening because the force acting on the object moves with its displacement at the same time...( this is roughly the explanation, I forget what my biomechanics professor said exactly)... that's pretty much it let me know if I'm on to something lol
We do light experiments.... I have light experiments using lasers and a venturi on my channel....I believe we created muons and you can see them using CMOS. From Cornell Univ.... "A measurement of the efficiency of CMOS sensors in smartphone cameras to cosmic ray muons is presented. A coincidence in external scintillators indicates the passage of a cosmic ray muon, allowing the measurement of the efficiency of the CMOS sensor. The observed flux is consistent with well-established values, and efficiencies are presented as a function of the number of photo-electrons collected from the CMOS silicon photodiode pixels".
The pics will blow you away.
Here I go with some far out ideas:
• Does time create space? Do extremely void regions of space generate added space-time?
• Does the vacuum energy, at some very slow rate, condense into matter? Possibly at a rate to almost offset the generation of space-time?
• Expansion of the universe is not caused by pressure but by first order local expansion, predominantly within the very nearly void regions of space.
• Nearby we, we observe space-time expansion. Farther out, we observe the more distant space-time expansion on top of our local space-time expansion. At ever longer ranges, we will observe exponentially greater space-time expansion .
• The several measurements to determine H₀ use observations taken at different distances, so differences in H₀ are to be expected. Calculating H₀ based on observations of nearby phenomena should produce a lower value than calculations of H₀ based on observations of very distant. phenomena
• H₀ is not a constant. It increases with distance from the observer. This notion could be tested against the existing observational data sets which have pointed ti differing values of H₀.
• The exponential expansion as seen in our most long range observation might explain away apparent inflationary period after the big bang.
• The universe may have always been expanding in this manner, and what we can see from out single vantage point might look very much like the product of a singular big bang event; an event which might not have actually occurred.