2. Inflationary Cosmology: Is Our Universe Part of a Multiverse, Part II 

What a tremendous gift these lectures are. Professor Guth is very patient and respectful of all questions and attempts to answer each one sincerely while gently dispensing with the many misconceptions (many of mine own).

I never thought i could understand how the universe form unless explained by the genius teaching professor Alan Guth

What a thoughtful listener. When Dr. Guth solicits questions from students, he is so attentive and eager to hear what they need to know. Of course, these are the smartest university students there are, but this cat's got decades of experience. He clearly loves to teach and to help young scientists learn how to think.

Has anyone noticed how politely Dr Guth listened to Q&A’s at his Public Lectures?

Pretty sweet. I get to take in a lecture at MIT and not even pay tuition. I love the internet *hug*

So much information on MIT... I wish i was a particle in a quantum state so i can watch them all at once.

What an amazing opportunity to watch and learn from this great teacher and physicist! Thank you Alan!!

I am in love with this series of lectures!

The summary was so good for non physicists and mathematicians like me.

Thank you so much for making this free.

I enjoy listen to your teachings Mr. GUTH. Thank you.

in one word,An extraordinary lecture..!!

33 views ! wtf? this is of the most superb content on the net!...thanks MIT!...& from a virtually guaranteed future Nobel Laureate mind u.....right up there with Lewin, WSU & Stanford's Leonard Susskind CE lectures.....I rec'n they soulda had "piano kitty" speaking instead...jeez 33?!.....free mind candy 4 all....1 way 2 help fix the future 4 sure !

Course starts at 1:02:00 1 hour 2 mins into the video.

How could you be bored by this? This is the most cutting edge stuff that human beings are engaging in as it relates to objective reality. These guys are trying to get to the cutting edge secrets of the universe. The implications these lectures have for our distant future on a cosmic scale cannot be underestimated.

When discussing the anthropic argument it is a selection effect not the fact that the universe is done for human kind, but when discussing that Omega is 1 and it is very rare this happens by chance while the inflation can explain it then it is not a selection effect but it is that bis theory is the right one. What I mean that at the end this kind of argument are more than by what we think it is right more then by a scientific demonstration.

Absolutely well done and definitely keep it up!!! 👍👍👍👍👍

Sir thank you so much for all of the information that you are providing to all of human kind ..

having access to something like that really makes me happy to live in this century !

I like this one. Look ahead he gets into some pretty cool stuff.

1:08:15 As of January 2022, Wikipedia still finds Hubble's Law, Lemaître's Law, and the Hubble-Lemaître Law to all be acceptable names.

If you find this lecture boring then I suggest the problem is .........you aren't in the right field. Would that I could be in his class.

In this pocket universe of a larger Youtubian multiverse , how unlikely is the dislike parameter to be zero and what divine selection helped you land here ?

It is not a prediction, it is a fit.

in minute 31, professor Guth said that weinberg and his collaborates calculated the effect of IS on galaxy formation .. they said it's about a factor of 5 or so .. I didn't get it .. a factor of 5 or so of what? please anyone has an answer ?

The Cosmological Redshift is NOT a doppler shift. Amazing how so few get this correct, most textbooks are wrong about this

What does a domain wall look like at the edge of a pocket universe? Would there be a smooth transition between local physical laws?

Thanks my hero

Thanks a lot ❤️

have just checked Wikipedia as per Guth's comment at around 1:08:15, and indeed it only refers Hubble's law, not Lemaitre's .. .

YOU ARE MY FRIENDSLY

I have a question -----> In this hubble's law how to find the r because the distance between the two galaxies are change by each milli second of time (Universe is expanding , galaxies are also moving ) then how to find the correct value of r(distance).

Thanka mit

I'm not a scientist, my background is computer science, and I think you guys grouse a lot. Even enjoy being unkind. What's not to understand about his lecture? It's actually rather basic if you pay attention. And he's not at all boring (again, if you pay attention). Keep in mind, he's teaching. This is not Comedy Central. And Sean Carroll does give lectures, many here on Utube on a similar level. Even deeper. Get to work!

Is the graviton only the quantum of attractive gravitational interaction?

As a cs grad, is it too late to change major now?

Genius

1:17:14 Nightmare of Dark Energy - 'Vacua'. 1:02:05 Standard Level of Detail..

Thank you MIT! Does anyone know of a website or something similar where there is a large collection of educational lectures from all types of subjects for free?

Is the entire mulitverse (if this theory is correct) 14 billion years old, or is it only our pocket universe that is 14 B years old? I watched another video from Dr. Guth an got a mixed answer. Thanks in advance.

It is already written as Hubble-Lemaître law, anyway :D en.wikipedia.org/wiki/Hubble%27s_law

Correct me if i' m wrong. Relativity theory, states that an object that travels at very high relative speeds (as light, near light or even faster than light, if it' s possible) becomes relative energy,that for that object point of view all surroundings become relative energy AND his relative motion will be more likely thoroidal for the relative surroundings point of view, and the relative surroundings will be distorted in a thoroidal pattern for the object point of view AND time contracts for the relative object, with contrary effect on the relative surroundings. Does this statement (if correct) imply that practically, an object surpassing speed light (which seems to be the last thing we can observe in relative movement) simply leaves the bounds of our universe in matter of mass/energy, direction and time? meaning that an object that goes faster than light in a relative way, simply DISAPPEARS from our perception of speed, mass, time? Does it mean that once that object has reached those incredible speeds, it falls into the indetermination realm, from our prospective? Which makes it VERY RARELY interact with our "universe"? If so, is it possible that randomness of mass, energy, direction, time "direction" and time "lapse" may create infinite possibilities, that randomly affects our universe, coming from infinite others? Is it possible for that that "dark energy" simply to be matter coming from other universes which RARELY interact with ours, given infinite space and infinite possibilities of universe laws of physics? It blows my mind, since i was a kid.

House-keeping ends 01:02:50

I have missed something 😎. I understand that the Universe is expanding, however does mean that the space between bubble Universes must as well expand, thus obviating most possible collisions? Why must that space (between bubbles) expand?

Present.🙂

Profesor Milan Cirkovic

How could two separate inflationary pocket universes "collide"? That would imply that there is EMPTY SPACE AS WE KNOW IT >BETWEEN< THEM! That would be nonsense in that space is being created by the expansions themselves so that what is in-between them is totally and completely unknown and is highly unlikely to be "space" in any way, shape, or form and thus in almost any scenario cannot be traversed by the expanding bubbles to allow a collision. We are still thinking much to narrowly! When you decide that different rules are involved with different universes, you have to GO ALL THE WAY WITH THAT THOUGHT! Remember, Khan was defeated by being too two-dimensional in his thinking when fighting the ENTERPRISE when using spaceships capable of going up and down, too. Do not fall into this trap with the multiverse...

I think it’s only because I’m much older than college-age (or even the average post-graduate age), I’m I understanding a great deal more of this lecture than I expected to. What has helped is that I’m not coming into this, at least for now, at the beginning of the 2nd class, with a bit more than zero knowledge of astronomy, cosmology, and even some basis quantum physics because I’ve been watching so many RU-vid videos on those subjects during the last six months or so. I’m having only one problem so far, and that is Dark Energy. I hear scientists and academics and others talk about the evidence that proves that dark energy exists. And I get it. But I keep thinking to myself that they jumped the gun. That they named it dark energy and yet they have no idea yet (or it seems so) what “it” is. Other than “force of a vacuum”, etc. which again, doesn’t mean much, really. Is the name “dark energy” a placeholder? Did they call gravity “gravity” before Isaac Newton? Or did they call it “falling” or “attraction” or some other word before Newton published his Laws? To me, it is still a mystery. I’ll get there, maybe by the end of the course I’ll figure it out. But wow. Thank you MIT! I guess I’m “auditing” this course, yes? It’s not even pass/fail! I’m not taking any exams. Wowie! This is awesome.

Patrick Collison at 50:37?

Pocket universes, multiverses, what the good man fails to mention is that all of these are purely mathematical constructs. None of these can be empirically confirmed in nature in any way. It is one of countless theories, nothing more and nothing less. And I find it frightening that he sells this to students as if it had been confirmed beyond doubt.

Multiverse??? Would Help if you guys Defined This One First!

13.8 billion years all leading up to the font comic sans

Only thinking one reality for life. Expanding slow down 5 billion years ago then speed up from then on. Example blow up a balloon in wind tunnel which is increasing its speed. That balloon is are our reality which expands that balloon can only expand so from its own energy which not infinite stopped 5 billion years ago. Now all other reality are expanding to that is increasing wind speed in the tunnel from all other reality expanding which the balloon start moving at speed of all other reality energy put together. That why expansion is increase in speed.

This guy is one of the best apperantly. Knows his shit real good alright alright. Does he have a nobel prize?

Righthh

from 52:10 to 1:02:49 - talk on boring.organization stuff. you welcome.

He's using a ThinkPad. :)

Once you let the cat out of the bag concerning an original big bang and an infinite number of pocket universes trailing behind the inflation detonation wavefront(s), we run into the idea that if such a situation can occur once in our "Cosmic All", which I call the "Omniverse", then it can occur an infinite number of times, each with its own basic set of rules totally unique from any other such Big Bang sequence. There is no reason whatsoever to assume that the overarching Omniverse has any rules whatsoever (what would enforce them?), so most of these expansions or whatever they may be are inconceivable to us and nothing that we can interact with in any way at all (obviously, even in our own universe, Dark Matter comes close to this, already, does it not?!), so the number of universes (I use this term very, very loosely) that exist (again, a loose definition) is infinitely larger than any mere multiverse based on one set of rules, no matter how variable in application they may be (10 to the 123 power is zero compared to infinity). Thus, no matter how arcane the concepts we might come up with are (in books, myths, comic books, plays, or movies), they all not only might exist but literally HAVE TO EXIST somewhere, no matter how impossible they might seem. Even a stopped clock is right twice a day is magnified to infinity!

If you’re bored by this, you don’t realize what you’re actually listening to.

At what point does it become useless to speculate about things that can never be proven or disproved?

String theory? Still?

Towards the end Dr. Guth says "this is delta t sub "O", not zero. Then he goes a few seconds later calling it "delta t sub zero". Just saying.

Clark Kent

Fairy tale

This lecture is almost entirely wrong. You can delete 90% of it as pure nonsense. Look, it's simple: The major process in cosmology, crunch/bang/inflation/expansion must be reformulated as galaxy local rather than universe wide. How? Via the AGN SMBH ingestion (crunch) and jetting (bang, inflation, expansion)..Isn't it rather obvious if you think about it? So that eliminates about 90% of the lecture as I said. It's really just that simple. What about expansion? You still get expansion and redshift but expansion is galaxy local - galaxies expand into one another. That resolves the Hubble tension because we would expect different galaxies to be in different stages of this grand recycling process. What about isotropy to 1 part in 100,000 -- well, we can see something like a trillion galaxies - all executing the same physics. What about multiverses and pocket universe? Oh, you mean galaxies? Yep, galaxies. What about the age of the universe - well it must return to unknown and probably a LOT longer if not infinite. This is actually good because it resolves a lot of tensions. See jmarkmorris.com.

Uh uh uh uh uh so distracting

This a brilliant, good hearted man. But he presents an argument not worth two dog lives. In the first half he depends on two admitted " miracles", reverse gravity, exceeding the speed of light and other axiomatic foundations of the very theories he espouses. What is more, the correlation he is so encouraged by have been shamelessly reverse engineered. That is, continual attacking of the data until a calculation fits it. Then declaring success. The most questionable example is the Higgs Boson Particle. The most expensive machine ever built spews billions of results which are selectively addressed until a few match the theories. Then culling of results are adjusted to find more confirmations. Have no religion. But I have a nose. What this good man says stinks.