Did Repulsive Gravity Jumpstart the Cosmos?

Wow I've been huge fans of Guth and Linde for years for their work on inflation. What a treat to see such a competent interview with both of them by Brian Greene.

The world is extremely lucky to have Brian and the World Science Festival. I imagine if we lived in an intellectually healthy society, these videos would top the trending charts. It is unfortunate this video has only 25K views in 48 hours when one considers the kind of trash on YouTube that gets millions of views in only a few hours.

Guth and Linde, heavy weights of Cosmology 🚀🪐🛰️🔭🍺

What Linde described beginning at about 12:58 -- the problem of how to explain how the Big Bang started at exactly the same moment throughout the small hot dense clump of primordial mass -- finally helps me understand why Feynman assigned a strange homework problem in a class at Caltech that I audited in the 1980s. He called it the "firing squad" problem. Suppose there are N members of the firing squad arranged in a row. Each member can communicate only locally.. only with its nearest neighbor on its right and its nearest neighbor on its left. They can communicate only at regular periodic intervals (like cellular automata). None of them know how many members are in the squad. All of them are programmed with the same communication & firing algorithm. Their goal is to all fire at exactly the same moment. Assume that at a random moment, one of them initiates the (local) communication that is to eventually lead to all of them firing at the same moment. Design the simplest algorithm that achieves the simultaneous firing goal. Feynman didn't tell us why he wanted that algorithm. But it would solve the problem Linde described, in a 1-dimensional toy primordial universe. So I'm guessing the Big Bang problem is what motivated Feynman to assign the "firing squad" homework. I submitted my solution, which seemed reasonably simple. But I don't know if it was the simplest algorithm, because Feynman didn't review any of the answers with the class.

Thank you so much wish to meet Mr green one day.

I love this lecture. It helps me understand the underpinnings of inflation that many others have either glossed over or ignored.

By the way the way hes sitting in a chair the 3d animations and dr guth and the other physicist are around him is truely amazing.

"A fantastically dense nugget...." best quote ever!!!!

Thank you!

This was a great segment. The question I was left with is: How do dark energy (DE) and dark matter (DM) factor into these theories? At some point they must be accounted for. What are the possible mechanisms for integrating such? Also (and I think [maybe] relatedly), the previous segment here on DESI indicates the employment of baryon acoustic oscillations (BAOs) as measures of the effects of DE & DM. I am not clear on what mechanism in Inflation would manifest BAOs (or if Inflation is required for BAOs to form). My first intuition is that BAOs formed after the Inflationary period (were they "locked in" during or after cooling?), and also, that they manifest across larger spatial scales. Still, given the euclidean nature of Space-Time, it would seem BAOs are dependent on Inflation. So any effects of DE and DM on BAOs should also inform the parameters for Inflation. Am I thinking about this correctly?