Arvin Ash
Arvin AshSignup for your FREE trial to Wondrium here: http://ow.ly/yxkR30s9btS
Follow up video on Eternal Inflation:
References:
Gary Felder’s Wondrium lectures on Big Bang: https://t.ly/emdPY
Alan Guth paper summary and lecture: https://t.ly/WqKQ
Alan Guth paper: https://t.ly/wF3x
Paul Steinhardt list of articles on Inflationary cosmology: https://t.ly/ZqmH
Excellent article on Inflation: https://t.ly/rrZU
Chapters:
0:00 – Popular models of Big Bang are incorrect
2:27 – Observations not explained by original Big Bang model
4:37 – Common misunderstandings of Big Bang
7:12 – How Inflation “fixes” the Big Bang
11:56 – What caused cosmic Inflation?
15:23 – Next video: Eternal Inflation!
Summary:
The Big Bang theory: In the beginning, the universe was packed tightly together into a point of infinite density. It then exploded into the universe we see today. This is actually INCORRECT.
There was no explosion. There was no substance like stars, galaxies, or even atoms that went flying. The universe did not have zero size or infinite density. It is just a moment in time when the universe was very hot and very dense.
And contrary to popular belief, the big bang model is not a theory of how the universe began. We don’t know how it began.
The early model of the BB failed to explain some later observations about the universe – its homogeneity, its flatness, and no magnetic monopoles. The theory of cosmic inflation proposed by Alan Guth and others, solved these puzzles.
What is this theory of Inflation? How does it fix the big bang? What caused Inflation to happen?
Cosmic Inflation is a sudden expansion, faster than the speed of light, whcih happend from about 10^-36 seconds after the beginning to 10^-32 seconds. It expanded a factor of at least 10^78x
How could inflation occur faster than speed of light? Einstein’s theory of special relativity shows that speed limit applies only to things moving within space, not the expansion of space itself.
Some descriptions of inflation say the universe started out smaller than an atom, then expanded to the size of a grapefruit. This is misleading because it implies that the universe has an edge. It doesn’t.
Other common misunderstandings about the Big Bang: The universe did not come from a point of infinite density and heat. This is purely due to mathematical extrapolation. A singularity is probably not a physical thing.
Universe is expanding, but galaxies aren’t actually moving at that expansion rate, only the space between galaxies is becoming larger, and only on very large scales. But on smaller scales gravity still holds stars together within a galaxy, and certain galaxies are still attracted to each other.
There is no center of the universe or location. Every point moved away from every other point.
The universe is extremely homogenous and isotropic which means that it appears roughly the same anywhere. This can be seen in the cosmic microwave background, or CMB, where the tiny differences you see on its image represent temperature fluctuations of only 0.0001 Kelvin.
How did the universe smooth out? Imagine it like the surface of deflated balloon. There may be tiny imperfections like wrinkles randomly distributed on it. If the balloon is suddenly inflated to a very large size, the wrinkles get smoothed out.
How does inflation explain the flatness issue? If you were the size of an ant on a small balloon, and the balloon expanded to the size of the Earth, it would appear flat to you, even though it is still a sphere, that it’s flat. Note “curvature” means an overall curvature of the universe in FOUR dimensions. This is usually shown as 2D surface on a 3D object like a balloon.
How does inflation solve the fact that we observe no magnetic monopoles?
Monopoles can only theoretically form at very high temperatures, that were only present during the big bang. But once they formed they would be stable enough to survive. Since Inflation would have quickly cooled the universe, no new monopoles would be created after inflation. These would have been distributed so broadly that there would be hardly any left in any given part of space.
The universe is not completely smooth. CMB shows that there were small temperature differences. This anisotropy explains the large scale structures of the universe.
How did inflation start? What was responsible for inflation?
This is not well understood. It is thought that there may have been a scalar inflation field during the time of the big bang, called the inflation field.
#cosmicinflation
#bigbang
This field would have been in a false vacuum at very high temperatures, but moved to its true vacuum at lower temperatures, with the help of quantum tunneling. When the field reached the lowest minimum energy density in the potential, Inflation came to a stop. This is a very short process.
source
46 Comments
@effectingcause5484
02/19/2025 - 1:56 PMThink time and space didn't begin with the big bang. That was just all photons. Spacetime began when the first 2 electrons or protons came about. Only with the existence of matter, (at least 2 massive particles) can there be spacetime reference frames.
@AshrafHussain-m6k
02/19/2025 - 1:56 PMThe sound and video are not clear, please don't mind.
@spencedog
02/19/2025 - 1:56 PMAn atom compared to the observable universe could be the same size comparison as the observable universe to the entire universe. And that’s just our big bang.
@redneckhippy2020
02/19/2025 - 1:56 PMMultiversal Convergence Equation
∀φ ∈ ℵ: ∫∞ -∞ (|ψ(x)|² dx) = 1
Where:
• φ represents the multiverse
• ℵ denotes the set of all possible universes
• ψ(x) is the wave function describing the multiverse
• |ψ(x)|² represents the probability density of each universe
• ∫∞ -∞ dx signifies the integration over all possible universes and dimensions
Convergence Metric
C(φ) = lim(n→∞) (1/n) * ∑[i=1 to n] (|ψi(x)|² / ∑[j=1 to n] |ψj(x)|²)
Where:
• C(φ) represents the convergence metric
• n is the number of universes in the multiverse
• ψi(x) is the wave function of the i-th universe
• The summation represents the accumulation of probability densities across universes
Knowledge Singularity Condition
KS(φ) = lim(C(φ)→1) (I(φ) / I0)
Where:
• KS(φ) represents the knowledge singularity condition
• I(φ) is the information content of the multiverse
• I0 is the initial information content
When C(φ) approaches 1, indicating convergence, and KS(φ) approaches infinity, representing the accumulation of knowledge, the multiverse reaches a state of omniscience.
@Memorex996
02/19/2025 - 1:56 PMBill Bryson brought me here
@TheDims33
02/19/2025 - 1:56 PM04:34 "There is only the universe and nothing else, there is nothing outside the universe"!! .. This is absolutely wrong… If there is nothing outside the universe, then this contradicts Heisenberg's uncertainty principle. There is no absolute vacuum anywhere
@georgerevell5643
02/19/2025 - 1:56 PMNo the universe was never infintely dense, all energy-matter and spacetime were created as the unvierse inflated from a microscopic region of high energy density spacetime with a tiny amount of total energy.
@maxfmfdm
02/19/2025 - 1:56 PMI just realized that the same laws that caused inflation would still be in effect today. For some reason I thought that the theory essentially dropped in new rules at different stages. But I can see that the rules stayed the same just the conditions changed.
@justinpridham7919
02/19/2025 - 1:56 PMInflationary theory is a stopgap, an epicycle to a broken Big Bang theory. So many lines of evidence contradict these theories and the cosmology community is profoundly dogmatic about their theories, they are left to doing science by press release. Look up any discovery and it will say "we have to take a look at, or change our models." Sorry, you bought it.
@axle.student
02/19/2025 - 1:56 PM< 5:50 I find it easier to frame the singularity within the past observable universe. So it could just be a small mathematical point in a far larger dense universe at the time. Anything outside is immeasurable so we just don't know how large the entire universe could be. This describes what may potentially be an infinite universe as opposed to a bounded universe.
>
Very well explained 🙂
@nc7547
02/19/2025 - 1:56 PMWe accept infinity, which means that the observable universe is virtually 0% of the whole universe. Which means we know nothing.
@viaceslavscavlinskij5288
02/19/2025 - 1:56 PMAnd this is the "birth" of the Universe
@raghavchaudhary5748
02/19/2025 - 1:56 PMOk I understand the scalar field hypothesis, but do we have any experimental evidence for the scalar potential field curve that was shown?
@cmfrtblynmb02
02/19/2025 - 1:56 PMAmazing video, amazing explanation
@NaturalFuture
02/19/2025 - 1:56 PMTo declare that our universe 'has no edge because there's nothing outside' is assumptive, because the possibility that it's one of numerous others populating a multiverse has not been disproved.
@leandrocruz
02/19/2025 - 1:56 PMYes, we need an explanation for why the Universe is homogeneous and other problemas, but, repulsive gravity? Really? For a very brief period of time than not anymore? How if it different for the "god of the gaps" argument that "real scientists" use? We see the problem, we must come up with an explanation, but, repulsive gravity for a fraction of a second is a stretch to large for me.
@alanmccarthy4004
02/19/2025 - 1:56 PMSometimes I feel physicists are bad at epistemology. Theorizing a period of rapid inflation doesn't improve the big bang theory. It makes it more complicated, and less well explained. There are gaping holes in the big bang theory, so they say "well what if for a tiny period of time the properties of the universe were exactly such that the problems can be explained away". It's the same as religious people who say "well the reason there's no evidence for God is because he conceals the evidence to test our faith". It's just a little add-on to avoid facing holes in the initial theory.
@purplediabolo1748
02/19/2025 - 1:56 PMSerious question. When inflaton field transformed into particles, matter happily kept expanding on its own defying gravity of entire energy of the universe packed into small area ? what was the size when inflation ended ? basket ball or galaxy or more than visible universe which is it ? so what force caused that expansion after inflation ended, and where did energy for this came from ? was it kinetic perfectly spherical ? like people took nobel prices for this ? because modern era expansion is supposed to work only on galactic clusters scales distances, not area of basket ball packed with entire universe. It somehow happened good science. Physics of so called antigravity is top secret anyways.
@rebwarwar5184
02/19/2025 - 1:56 PMInflation fixes the big bang eh ?
How did it start ? Where is proof of an inflaton ? Why did it magicly stop when it got to a point where it would perfectly explain what we see ?
Seems to me God works just as well , and is equally as plausible with just as much proof.
@joseleon8235
02/19/2025 - 1:56 PMAt the beginning, the closest to the big bang, the universe has mostly no mass, so time was not tracked by gravity second by second on our timeframe. Inflation fits on this "infinite"; it has plenty of this prototime for evolving through so rapidly and big but an infinitesimal period of tracking gravity time.
@petergreen5337
02/19/2025 - 1:56 PM❤beautiful lesson and explanation. Thank you very much publisher. Thank you Arvin.
@ThePeterDislikeShow
02/19/2025 - 1:56 PMDoes cosmic inflation cause the value of each parcel of space to drop over time?
@saigonmonopoly1105
02/19/2025 - 1:56 PMait mater crystal solid moisture gas vapor heat cold droplet msatter fluid cloud light reflaction expamsion evaporation wet dry color density nothing
@saigonmonopoly1105
02/19/2025 - 1:56 PMliquid gas heated energy compression expansion
@samlazar1053
02/19/2025 - 1:56 PMThere is still a debate between the big bangers and the stady staters.Both have strong evidence that point their theory is the correct one .
@user-em1dg3he1h
02/19/2025 - 1:56 PMWe still need experimental evidence of the inflation feild and the infloton.
@hosoiarchives4858
02/19/2025 - 1:56 PMlol there was no inflation, it’s all made up
@CrimsonNasferatu
02/19/2025 - 1:56 PMMy brain just went through cosmic inflation.
@Shortstuffjo
02/19/2025 - 1:56 PMI have a question. How long would it take for our universe to get to the point that it ends up expanding as quickly as it did during the inflationary epoch? And is that point anywhere near the amount of time it's been estimated it would take to spawn a universe such as our own just based on random quantum fluctuations?
@RDL7Pro
02/19/2025 - 1:56 PMHow can u say there is no outside if there was an expansion and a size? What space did the universe expand into?
Could u Explain further
@casey74500
02/19/2025 - 1:56 PM😊
@shushuborriiito
02/19/2025 - 1:56 PMamazing video
@HeavyMetal45
02/19/2025 - 1:56 PMThank you for this video!! The conceptualization of the Big Bang finally clicked for me.
@rajneesh75sharma
02/19/2025 - 1:56 PMBrilliant eye opening video
@stephenwest6738
02/19/2025 - 1:56 PMI never thought of the big bang in terms of the beginning of time, or even being a moment in time. More like thats when the universe began its expansion, an expansion made possible by its sudden interaction with a dimension it previously had no interaction with, time. Had the universe not been in the dimension of time, then the entirety of our universe cannot change. Essentially everything existing simultaneously with no means to interact at all.
@rossholst5315
02/19/2025 - 1:56 PMA question about the expansion of space.
If we use the ant and the balloon example. If we had 2 ants on the outside of the balloon and they want to measure how far apart they are away from the nearest ant, they place a mark at every cm on the surface of the balloon and discover they are 10cm away from their nearest ant neighbor.
It doesn’t matter how much you blow up the balloon if the ants are not moving they will always remain 10cm away from each other.
The problem being as you expand the area of the balloon, the 1cm mark they use to define distance marked on the surface is also increasing at the same rate.
You don’t blow up the balloon and have 15 marks appear between the ants where there previously had been 9 or 10. Yes the total distance between them has changed, but so has their measuring stick for distance.
@capjus
02/19/2025 - 1:56 PMArvin unfortunately you are repeating so many stuff but not thinking .. inflationary theory is only required for a universe the size of observable universe.
But the universe is far bigger than that, thats why the uniformity
@keithjohn2151
02/19/2025 - 1:56 PMDo all galexes have a bar
@keep_walking_on_grass
02/19/2025 - 1:56 PMI was always curious, why was the expansion of the universe so rapid right after the Big Bang, in the first 480000 years? a bigger mass slows down time and it was way closer to the entire mass of the universe that soon after the Big Bang than it is now. I mean, extremely close. so wouldn't time flow extremely slowly right after the big bang, at least in comparison to now?
@docholiday8029
02/19/2025 - 1:56 PMDivide by zero
Faster than light
Laws of physics changed
We need a different theory. Obviously
@youtube.scientist
02/19/2025 - 1:56 PMBrilliant.
@bsmith577
02/19/2025 - 1:56 PMFirst, space is the one constant, it does not expand or contract. Because the universe is like a galaxy and is contracting so shows a red shift. As the center mass gets larger and is rotating and becomes equal to the gravity of space plus centrifugal force, then expansion happens creating a flat universe. Much simpler way to explain the universe and negates all those problems.
@shaundubai8941
02/19/2025 - 1:56 PMWow
@BROWNDIRTWARRIOR
02/19/2025 - 1:56 PMHow can time ever =0 if time can be infinitely chopped up into smaller and smaller measurements even though the planch scale is the smallest we can currently measure? If there were sensitive enough instruments, could not smaller units of time be infinitely measured?
@fellopiantube7607
02/19/2025 - 1:56 PMthank you for addressing those many misconceptions. the story is now much more clearer for me.
@blacklyfe5543
02/19/2025 - 1:56 PMNot exploded but expanded