Cosmology and the arrow of time: Sean Carroll at TEDxCaltech
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- Опубликовано: 12 май 2024
- Sean Carroll is a theoretical physicist at Caltech. He received his Ph.D. in 1993 from Harvard University, and has previously worked at MIT, the Institute for Theoretical Physics at the University of California, Santa Barbara, and the University of Chicago. His research ranges over a number of topics in theoretical physics, focusing on cosmology, particle physics, and general relativity, with special emphasis on dark matter, dark energy, and the origin of the universe. He is the author of "From Eternity to Here," a popular book on cosmology and the arrow of time, and of "Spacetime and Geometry," a textbook on general relativity; has produced a set of introductory lectures for The Teaching Company entitled "Dark Matter and Dark Energy: The Dark Side of the Universe;" and is a co-founder of the popular science blog Cosmic Variance, blogs.discovermagazine.com/cos....
About TEDx, x = independently organized event: In the spirit of ideas worth spreading, TEDx is a program of local, self-organized events that bring people together to share a TED-like experience. At a TEDx event, TEDTalks video and live speakers combine to spark deep discussion and connection in a small group. These local, self-organized events are branded TEDx, where x = independently organized TED event. The TED Conference provides general guidance for the TEDx program, but individual TEDx events are self-organized. (Subject to certain rules and regulations.)
On January 14, 2011, Caltech hosted TEDxCaltech, an exciting one-day event to honor Richard Feynman, Nobel Laureate, Caltech physics professor, iconoclast, visionary, and all-around "curious character." Visit TEDxCaltech.com for more details. 
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i just came across this today, and coincidentally, also just finished reading sean's book on the bus this morning! this is basically a summary of it in 15 minutes. he's an amazingly clear, articulate and concise speaker! i could listen to him talk about this stuff for hours on end. if you want a lot more detail, i'd highly recommend 'from eternity to here'.
Which book?
Drs. Sean Carroll and Brian Greene do an exceptional job of bringing physics and cosmology to the public commons. Thank you both.
I love these TED Talks, thanks for posting it online.
Thank you TED Talks, Thank you Ms., Mr. Carroll for being my colleagues and testing my ideas on our existence, I cant wait to work with all of you, peace and love, Doug.
Wow this dude is amazing. I mean of course, I suppose. I rarely ever regret not having good professors, because learning is a personal thing, and I am self-taught in my career and all of my hobbies and interests. But this dude makes me wish I had someone like him. Kids are so lucky today, with RUclips and Coursera, and all that. Jeez.
I understood your analogy as minimum variations vs maximum variations. Easy enough to grasp that way.
I love that you left us with a big open question for us to ponder and discern. Thank you!
Totally enthralling and down to earth explanation in laymans terms with some humour. I enjoyed this presentation and will watch it again. A good wish likely granted. Thank you.
This is still what I consider to be the best Ted talk ever released. It's grounded in science (not this soft-science shit they've been spamming my feed with lately :[ ), it addresses the current problems within it's field, it's highly factual, and it's content at large is very thought provoking. Cheers, Misour Carroll.
Very good info!!! This is an invitation to see a theory on 'time' with an emergent uncertain future that gives us a new understanding of quantum mechanics.
It's annoying that these are so short.
You want him to be taller?
If you want to see Sean talk more look up Joe Rogan podcast, he has several podcasts with Sean that are great and are several hours long.
Impressed by how easy Sean Carroll talks about these subjects. Thank you!
His lectures are excellent, I wish he was my professor
Easy, you just have to go to Caltech.
He is ... videos, many of them available.
Lucky guy
I have gone through his lecture in TTC videos , excellent 👍👍
Sean Carroll is excellent. He got one thing wrong near the end. He exclaims he agrees the universe is expanding forever. Then at 12:54, he talks about how all of the cosmos will die out as if fact. That is quite a statement to propose. If the universe is expanding for eternity as he claims, new stars can be forming, new space/dimensional pockets, etc. Infinite expansion of nothing? Even if true, for infinity/casualty that should at the very least cause something to happen, given a timeframe of infinity. It will never be an infinity of nothing, we will still always have cold debris such as rock, ice, and old technology for infinity, and if something is truly infinity, then by smashing together something is bound to happen. So rest assured most scientists don't think that far, when we found we are expanding indefinitely it meant a chance for life to survive. Even advanced civilizations prepare for it in several ways, creating wormholes to other universes, if you want to get really deep.
Awesome video, great talk. Fun & informative.
Prof. Carroll's talks are always engaging.
Wow, he hardly took a breath to cover inception to extinction. Amazing lecture!
this is the ultimate conversation
Sean has a great way of taking an immense exhausting subject and making it immense and exhausting.
John Zebell indeed why they just don't realise that e=mc2 is an ancient idea older than modern Newtonian physics. Probably because they don't want to admit they need to take CGJungs ideas into consideration
The Cosmic Chicken! Of course!
One of the best Ted Talks ever. Mahalo!
I've always wondered where do forces play a role in this 'randomly moving particles' (statistical mechanics) view of the world. Although I cannot calculate anything, say A is the event of a galaxy forming, G is the existence of gravity, S is the distribution of matter through space in the early universe, the probability P( A | G & S ) is almost 1.
Particles aren't just randomly moving, they exert forces on each other that increase the probability of forming structures.
A
Fascinating! Especially the part about the apple pie!
Great speech Sean. I've become more fascinated the past few yrs with the origins of the Universe & very quickly I recognized you were headed toward our supposed beginning in the immediate aftermath of the big bang in the "Egg of Life." Where we all truly were as 1 within a much smaller frame. I believe the egg "split" with the intro of gravity into the equation which drew out matter from the egg continually expanding the Universe since. Really interesting your thought that maybe the big bang isn't our origin. The more I learn the less I'm bound to our Earthly mindset but realize that our Universe seems to be a reflection of itself so we are able to like you said not only know our past but can ostensibly learn much of what's ahead or is it actually behind? My question comes back to why? Obviously there's intent behind existence so where did that originate? Was the big bang essentially a much higher intelligence than we cannot fully comprehend? I definitely don't see our origins from the big bang as a fluctuation something had to give us the matter that allows us to know what we've come to understand. I'm so looking forward to the rest of eternity & the twists & turns in our existence.
Can someone explain Feynman's debunking of Boltzmann's hypothesis to me? I'm not really sure of what he means by that expectation of order...
Theory: Objects in the universe that are further away are accelerating faster because of gravitational pull. The initial big bang explosion was so high in energy that it was strong enough to push objects away from the universe's gravitational core. As objects continue to get pushed outwards from the core, it accelerates faster thus causing less gravity to have an effect on the objects being forced away. With less gravitational force, there is more acceleration.
Time is affected by the density of space and/or matter, and, it seems reasonable to me that an object's 'observed' acceleration must reflect this. If we assume that 'new space' is not being created and that existing space is expanding, then the 'density' of that space would be more rarified toward 'the edge' of the universe and show non-linear results in the measured velocity of galaxies. Time would run faster the closer you look to the edge of the universe. This would require no dark matter or dark energy.
I'm not refuting anything but merely offering up an idea.
How is time affected by the density of matter?
@@mykhailohohol8708 it slows down
Question: Can any answer pl? In a positively curved Universe, acceleration of distant supernova would mean - beginning of contracting phase. Is it correct? If it is correct why it is not predicted in that way? I think there is no dark energy. In a positively curved universe galaxies should accelerate in contracting phase and would be seen receding even if they are approaching (for curved space).
Great, very interesting talk. Thanks.
Wouldn't cause of relativity the past and the present and the future all exist simultaneously, so there would then appear both a big bang and not one simultaneously, it just depends on where you maybe located and how fast you maybe traveling whether you maybe seeing a depiction of a big bang or not, correct? If you could travel so fast then maybe you could travel to a place where the big bang had not yet started and so forth, so time maybe an illusion like the movement of a big bang through space it maybe relative to the observer.
There is something intrinsically assinine and simplistic going on in here that is difficult to describe
We’re evolving and we’re going back in time
So he's saying that, as one of the many possible combinations of particle arrangements in space time, they once assessed into a single point, and have been moving apart ever since. That is our experience of our universe since the Big Bang. A low entropy turning to higher entropy period. So we experience the arrow of time. Sound correct?
But I'm not sure how we hopped from that, to the multi-verse.
great video. I understand entropy a little now.
I wonder, ¿What relation is there between the arrow of time and the big inflation of the first instants of the Universe?
Powerful , keep it up
6:24 from _Time lapse in the future_
Watch at 0.75x speed for more time to absorb everything!!
Rewatch it now to test your knowledge retention ;)
11:20 Pie in the sky joke becomes funnier with the Boltzmann's suggestion
3:30 Boltzmann portrait looks like it came from the Fullmetal Alchemist screen-in-between.
Fascinating! :-)
is there an underlying function,we can't see, that dictates what outcome will actually occur out of the many possibilities??? coz even if we make a computer program, that is programmed to accept one possibility out of the many, it has to rely on an underlying function. it can't generate randomness on it's own....
The answer to multiverse is that if Einstein is always coorect that particles become waves at superluminal velocity then beyond the expansion luminous horizon no matter exists hence entropy there decreases normally. His hypothesis predicts antilife IMO!
What will happen if the entropy keep increasing?
my brain! it can barely take it.the flow of knowledge into my head is glorious right now.
Thank you for your reply.
But why must infinity create infinite fluctuations/events/systems and compositions?
Let's say, instead of particles we have all the letters of the alphabet; Now with infinite time and letters, what is to say that all possible words and phrases must come about by default? That universe could consist of scarce amounts of low entropy systems and fluctuations, such that you may find half the words of shakespeare some where once, perhaps, but mainly it would be A's and O's for infinity.
Please explain how you can have energy...without 'stuff'. How do you know there is 'energy' if you cannot measure a temp or observe motion.?
because the interactions of things observed in the universe couldn't happen if the only thing there was is visible matter and measurable energy. Like gravity is not expected to work if it's only originated from the mass we can observe in the universe, it would be too weak. by calculating the difference between the mass needed for gravity to work as it does and what we currently observe you can estimate the mass of dark matter in the universe. Sixty symbols and other science channels have some good videos explaining that better than i would.
Im wondering if this idea has a strong connection to mandelbrot fractals?
@nifedonkey3 Bold, unfounded conjecture. What have you to support it?
What exactly is a "precisely similar calculation"? [8:08]
It is approximately the same math but exactly the same idea. Maybe.
Could we have an Arrow of Time for each object? The organization is not formed at the beginning of the Universe with a big bang but is being formed here and now as a process of continuous spherical symmetry forming and breaking. The electron is the most spherical object in the Universe this forms the organization for statistical entropy or disorganization that we have in the second law of thermodynamics. By the way this is an invitation to see an artist theory of the physics of ‘time’
What is the universe expanding in to?
where is the equal and opposite enthalpy that must necessarily accompany his alleged entropy ? For that matter, where is the equal and opposite compaction that must necessarily accompany the alleged expansion of the universe?
Universal chicken!!! Best explanation of God I've heard so far :-D
None of this is real.
It's not !
Just a thought or two.. Gravity is the sum of all possible timelines which we see as superposition states, ie the primary principle of quantum theory. All particles and wave perturbations are entangled with each other. The closest those wave perturbations are in their respective fields to each other in 3 spatial dimensions, the more entangled they become resulting in spacetime curvature around those more entangled regions. Could this be what gravity intrinsically is? ... Or have I had too many shots of Jack Daniels this evening?
I think latter is the case.
@@Anskurshaikh Hmm yes I concur. Apparently I've been drunk theoretical physics-ing again.
@@MissChanandlerBong1 well do you have a Phd in Physics?
@@Anskurshaikh lol Not as yet mate. How about you?
Every system with a finite ending time will fail to be time-reversible, and since current physics' classic solutions are always never-ending, there is a flaw in the traditional mathematics' tools used: since they are always holding uniqueness of solutions, they will never model accurately phenomena with finite duration, which left us with models that don't show the direction of the arrow of time on their 2nd order differential equations.
As example, I have found an interesting issue with classic pendulum equations: if you consider the Drag Force as the classic Stokes' force:
F=b*x'
the pendulum eq. is (for some positive constants {a, b}):
x'' +b*x'+a*sin(x)=0
a diff. eq. that under the transformation:
t --> -t
is not time reversible! (which is commonly only atributed to entropy by the 2nd Law of Thermodynamics).
But if instead the standard Drag Force:
F=b*(x')^2
is used, the diff. eq. becomes time reversible, but its solution are never decaying!... so it is needed to modify the Drag Force in something like:
F=b*x'*|x'|
to recover the decaying solutions, so somehow, the condition of been non-time reversible is required!
But even with this improved drag force, solutions are never-ending in time, since the diff. eq. holds uniqueness of solutions due Picard-Lindelöf theorem... but, if I change the Drag Force by something like:
F=b*sign(x')*sqrt(|x'|)*(1+|x'|^(3/2))
which resembles Stokes' Law at low speeds (non-near-zero), also resembles the quadratic version at high speeds, but introduce a non-Lipschitz component at zero speed, now the differential equation:
x''+b*sign(x')*sqrt(|x'|)*(1+|x'|^(3/2))+a*sin(x)=0
will be having decaying solutions that will achieve a finite extinction time t=T< infinity (so x(t)=0 exactly after t>T), also with a diff. eq. is not-time-reversible. Hope you can review this, is easy to see it in Wolfram Alpha.
I have a problem in the phrase "looking back in time". My very simplistic view is that a "moment" at my location is the exact same "moment" at any point in the universe or beyond the universe. The fact that the very distant "moment" can take numerous light years to tell us that it (a particle, a group of particles a star) has just had its moment for me to observe that moment on earth I will need to live all most forever to witness the arrival of that moment at my location . The conclusion that I draw is that each and every particle has a "moment" in which every other particle has a mathematical fix in space. If you will, a "Universal General Positioning". What the human race is observing is "Change" in the absolute coordinates of all partilces in what ever form. Being that is the case, the need to have a "dimension of time" becomes redundant. After all, the measurement of time is one that we humans have invented and is a concept to allow us to organise when and where our bodies our things, our World can be coordinated. Given that, once Einstein got to Special Relativity he got stuck on General Relativity and then he really got hung up that Gravity is observed but cannot be explained. Einstein had a buddy, a mathematician, who he turned to with his problem. His problem was given that a particle with mass is travelling in a straight line through space how can a second particle travelling through space on a different trajectory be mathematically cleared to meet with each other. Thats when Herman Minkowski offered a solution which was to cause a depression, a vortix, in which a particle can be taken through a change of direction by following a straight line which has been curved. It is referred to as Minkowski Space Time. This clever solution has never been proven and has led science, in my humble opinion up a blind alley trying to bring together Special and General Relativity together as one.
The concept of travelling back through time is therefore binned as to travel, "to return", to a original form would infer all the particles of the universe would have to conform in a mathematical relationship to each other coincidental to the form that is anticipated by travelling back in "time". Similarly, the concept of travelling forward through time would infer an arrival in the future would need all the total elements of the Universe to be in lock-step in accordance with the mathematical lock on their postions at that "time" chosen. If time is binned it will make the understanding of our universe that much easier as I feel confident the solution will turn out to be a very precise but simple one
"Back when I was your age..." ??? He's never been my age. I think hes flipped his ever-lovin universal arrow of time.
His audience is college students.
@@jenni1111100 you mean robots
Did the Organizers also ask Sean to finish with his Jazz Combo?
I like the idea of a multiverse- but i prefer to think of these as branching timelines for each computational point or virtual particle- not "parallel" realities as some suggest. You can't have time without space, and visa/versa, so there's no doubt in my mind that Sean's radical ideas will be vindicated. Yes, it's a set of alternative universes defined by tensor networks, or maybe a "co-existing" multiverse of alternative timelines for each, virtual particle. We have free will, and sometimes do things that statistics and AI supercomputers fail to accurately predict.
My favorite elements are candium and ballonium. The candy and balloon atoms respectively....
When he says that there is the same amount of energy per cubic centimetre (same density) even though the universe is expanding, doesn't that imply that energy is 'created'?
+Calvin Chen Technically dark energy is being created not energy per say but yeah I've been thinking the same thing
+Calvin Chen Would energy be created if you were to pull a rubber band 3 meters from your thumb? That's a simplified model of the big bang theory. It implies that the energy has always been there and it's expanding faster than light.
Space itself is also expanding... so a cubic cm is also getting larger
Yes, energy is created. The observable universe gets heavier and have more energy. The UNIVERSE including the unobservable is and was always infinite in energy.
Proud nerd moment when I was like, "I know this face, but from where.... Oh from Sixty Symbols!" haha.
14 is one such. To create more entropy means random numbers will have to have additives rather than subtractive. There is no subtraction or division in physics.
I could listen to this guy for hours.
16:00 min. Instead of having energy; what if Space had negative energy?? That way it would need to acquire energy just to get up to zero or neutral? Just a thought...
We can always roll it down a steep Nebula and try popping the clutch.
Awesome talk
Was there fields in "space" before the big bang?
this confirms what I believe, and that is that the big bang was a regional event in an infinite universe caused by the collision of two universes within a multiverse. Such collisions would cause the release of energy that could cool and form stars and planets.
As for dark energy being the matrix of energy that is the universe, thats bang on. All things are energy, or another way to put it, all things are spirit and what we, the observer sees as physical is due to a limitation of perception.
@cristianfcao That is why you need to learn. Take a lot of Mathematics (Calculus, Differential Equations, Partial Differential Equations, etc) , Physics (many components), Astronomy, etc. Then, after about 6-8 years of graduate school you have a solid grasp of this. Throw in a little post-doc work in there also.
He does a good job of explaining things to laymen. I.e. Explaining things to someone with maybe a high school science background.
It seems like the Universe once expanded to a point of thermal equilibrium is the same as the universe before the big band at thermal equilibrium. What about a Bose-Einstein condensate could it be state of matter at the point before the big bang at the end of that expansion?
None of you is using the correct definition of entropy. It isn't a measure of non-homogeneity, it's the logarithm of the number of possible microstates associated with a certain macrostate, ie the number of ways to make a certain arrangement of matter. The early universe was smooth, but it was composed of relatively few, very high-energy particles. Now it's composed of mostly low-energy particles, but a lot more of them, so there are many more ways to arrange it, and entropy is much higher.
No chicken. It's eggs all the way down. :)
WHAT? Do you deny the undeniable truth that Adam and Eve rode on the back of a giant chicken in the garden of Eden? BLASPHEMER! HEATHEN!
The turtles disagree.
I've always thought that was the answer
Could dark energy be a force with less gravity? Like since we expanding the dark energy is becoming more and more observable cause less gravity is pulling on it.
Maybe it's not a "push" but the resultant backflow of a "pull"
Seems plausible, especially if you consider the electrically charged plasma theory.
the past is also added some of the knowing things go in the sens inverse of time .....
Thunderbolts of the Gods utilizes archtype imagery from around the world that suggests that they were all influenced by witnessing the same events. It postulates that the planets were much closer together giving off plasma displays that can be reproduced in a lab.
oh. that explains it. You are an electric universe weirdo lol.. go on with your bad self. there is no hope for you.
after a bit more study i definitely wanna read up on it. I like any book with the format blank of the gods my new favorite being food of the gods which tells the theory that human brain size was caused by pre-modern humans eating halucinagenic mushrooms. but i mean its trying to explain phenomena which are already explained by gravity. Stars are formed by masses of hydrogen with enough gravitational force to start fusion. the resulting star is electric true but resulting from gravity and fusion
Expanding into what?
Space doesn't necessarily need to expand into something. Instead of imagining it expanding, imagine new space being created between objects. It's a bit easier to comprehend this way.
Could dark energy actually be the entropy of the universe writ large?
That was fun!
jack parsons worked at caltech too they even named a crater after him
Man, i'm trying to find some way I wouldn't take that the wrong way if it was me. "Hey Elastic, we named a pothole after you, come check it out"
the first 3 words of any sentence in such a Sean Carroll talk should be: "we assume that ..."
It thinks for itself....It creates itself....
Ladies and gentlemen, I give you...
THE UNIVERSE!!!!!😍
Can't give something that owns you.
Anyone else notice it's the same place as the big bang theory is set (Caltech university Pasadena California)
What if the "accelerated expansion" of the universe is simply due to the slow spreading of galaxies and their gravity is capable of slowing down the light from said galaxies over immense distances. Would that not create the exact same effect as an accelerating expanding universe?
I mean we do know that light cannot escape a blackhole due to its gravity so why couldnt it be feasable that the collective gravity from every galaxy behind a photon could slow it down to the extent that it makes it seem like, from where we are, that everything is accelerating away from us
Every Once and awhile I'll swear I'm listening to Alan Alda giving a lecture.
45 years to go!
43 now...
@fryingsok id like to see you do a similar speech as intriguing, entertaining and within the time limit whilst GETTING ALL PRECIOUS DETAILS JUST SO.
@jknengr796 I really don't get your comment. Of course you need to learn a lot to better understand cosmology, so what? I'm just saying he used a misleading mental image. You don't agree?
BTW I LOVE listening to Sean Caroll and I appreciate his effort to explain science to the laymen as you've said. I'm not sure his style is one of the best (he always speaks too fast and presupposes a high level of familiarity with many concepts) but I really like him and appreciate his work.
They don't know. So much speculation short of confirmation. Our knowledge of the universe is in it's infancy. So much to learn and so difficult to investigate. I'd love to be around a hundred years from now to see what our best cosmos are saying then.
14:45 when you find out you have still have 1 egg left after thinking you ran out days ago
TIME flies like an arrow, fruit flies like a banana.
🤣🤣🤣🤣🤣
@@thehellyousay I was quoting Grouch Marx
Now we just need to find a Universe making machine infinitely more complex then the un-explainable Universe that we see, that's outside our time and space. Some physicist have this bad habit of just pushing the problem back a step and saying "solved". One of my favorites is Francis Crick who discovered DNA. Very bright obviously. He admitted there just isn't enough time on earth to explain such complex life forms by un-directed, blind, random forces with no signs of mistakes or transitional forms in the fossil record. Let only the origin of life with it irreducible complexity that has to come into co-existence all together. His answer: Earth was seeded by another planet! Now we just need to find the planet where amino acids can form to make a functioning and stable 3D folded protein against the odds of 1 in 10X77 power. And that is just one protein. We are so eager to have an explanation of the really big questions but the science is not there yet obviously.
The universe is a collection of minds. Consciousness came first.
Does it mean that there is an apple pie somewhere in the universe?
probably more than one, and perhaps even an infinite number of variations of the same one, and each unique apple pie, having infinite itierations in infinite parallell universes in an infinite multiverse....
Feynman says nope
Yep - which explains what the teapot is for as well...
There's an apple pie in my freezer, want me to crack it out? Sounds gooood, heat it up, plop some vanilla on it, BLAM, you know you gotta let that vanilla melt a little.
The Universe is overflowing with Apple Pie. It's an applepieverse. Get you some, brother.
In the midst of this awesome lecture is a 1968 Fender Super Reverb
Looks like it belongs there
Excellent. no more no less!
This is the most mind boggling part of this lecture: "The amount of energy in the vacuum of space remains the same as the universe expands"
Googled it and came across what appears to be an official site that claims to have peer reviewed articles supporting the theory yet once you click it only says "There are many peer reviewed papers on electricity (electric fields and electric currents) in space. They do not necessarily cover aspects of the "Electric Universe" theories." lack of peer review = bad sign. I like the ancient alien theory but even it has peer reviewed articles. Thunderbolts of the Gods..the title is very telling =)