Cosmic inflation: is it how the universe began? - with David Mulryne

0:31: 🌌 The universe was different before the hot Big Bang model, with everything closer, hotter, and denser. 5:42: 🌌 The speaker discusses the special nature of our universe, the concept of inflation, and the size and structure of the universe. 11:34: 🌌 The universe was very smooth and even when it was young, with only small variations in temperature. 16:49: 📡 The law stating that galaxies that are twice as far away are moving twice as fast is a result of the smoothness and uniformity of the universe. 22:13: 🌌 The image is being stretched to show the expansion of the universe, with galaxies maintaining their relative positions. 27:21: 🌌 The universe is expanding, with everything getting further away from each other as space-time itself grows. 32:59: 🌌 The speaker wants to show the expansion of the universe in a more realistic way. 37:55: 🌌 The universe is smooth and homogeneous, with everyone experiencing the same expansion from the Big Bang explosion. 43:10: 🌌 The homogeneity problem addresses why the universe is so smooth and homogeneous everywhere. 48:15: 📈 Exponential growth is illustrated by taking something and multiplying it by a number greater than one, causing acceleration in growth. 53:14: 🌌 Inflation theory explains the homogeneity and horizon problems in the universe. 57:43: 💫 Quantum fluctuations in the field during inflation give rise to the structure and formation of galaxies in the universe. 1:02:35: 🔬 Inflation in the universe can lead to Quantum fluctuations and the creation of disconnected bubble universes with different physics. Reca

For those , with some basic PS knowledge , skip to 36:09 . That`s where he gets on the topic of his lecture.

Kind of a bummer that I'm about to spend an hour watching this and I already know how it ends.

It's amazing that we worked any of this out.

This presentation is mis-titled. It should have been called, "An Introductory Overview of Cosmology and the Big Bang". The speaker doesn't really start talking about inflation theory until the last ~10 minutes of the talk and simply lists some of the various models rather than discussing them. It's a nice talk, but it's an introductory presentation of cosmology for a lay audience, not a discussion about the merits of, and issues with, inflation theory.

15:40 the way the whole universe is summed is beautiful to watch. We felt very small in this comparison 😂

Poor guy was nervous at s start. He realised that he fggot the bucket analogy wrong by a factor of 10, and while wondering about it said Stars instead of Galaxies in our observable universe.

The famous desk looks great! Glad to see it's back home.

The bucket of sand analogy always works well, what really does hit home though and how I explain the scale is by adding the fact that between each grain of sand is ~4 light years, and would take the fastest thing we have made, 73,000 years to make 1 single hope to the nearest star!! That's when you start to realise space is big, very big!" ;-)

0:52 “ Everything in the universe is getting further and further away from everything else”. On a more human scale my socket set is absolute proof of this.

Thank you. This was an excellent talk by a gifted explainer.

He said when you zoom in on anything it becomes smoother. I remember my math teacher showing us this with Integration and how you zoom in on a curved line and it becomes more straight. But this is not always the case. There can be what looks like a straight line from a distance but when you zoom in you see it is a high frequency sine wave or some other jiggling function. The Mandelbrot function never becomes a smooth line. Zn+1 = Zn2 + C . Then I thought of a circle. 2πr If you look up the definition of a circle , it has a center point and a radius and the circle is defined as all the points that distance from the center. But in the real world you have quantum fluctuations and the center of any circle is moving around and vibrating. The radius is also not a fixed distance because of the uncertainty principle. So now if you make a circle with these things in mind , and you zoom in on the circle line, you will see it as very wiggly and the distance around this circle will not be 2πr It will be higher. 2πr is the distance around a circle in a classical world where planks constant is zero. Which is obviously wrong. To get the actual distance of the circumference of a circle you have to use QM and do what Feynman did and add up every possible circle there could be and average out the circumference. The same things goes for addition like 1+1. You need to add up all the possible ways you could every add 1+1 together. If will be higher than the classical 2.

He is a very good speaker. I find the mix of advanced topics and basic ones to be puzzling. He almost assumes that you are familiar with non-Euclidean geometries and Heisenberg's Uncertainty Principle but sketches out in a very basic way. I kept thinking yes yes but please get on with it and give the topic some depth

Lovely presentation. Thank you.

Is it possible to have a big bang in middle of university to see what would happen.

The hypothesis of inflation seems artificially forced in to salvage a theory of the early universe that just doesn't work. Sir Roger Penrose's hypothesis make a lot more sense.

god I love experts that can tell me all about the history of the universe but cant tell me for sure how all the water got on our little planet

I mean this with no sarcasm or hate: what an interesting accent. At times you sounded like you were from Northern Ireland, but at others almost RP or very upper class London, and it mixes in such an interesting way.

this is all so unbelievibly real....

This is such an awesome presentation on what we know about the ultimate “origin story” = the Big Bang!