Four Forces – Gravity

This week’s videos are all about gravity. However, before embarking on the main videos about the four forces of nature, I decided I needed to make Noether’s Theorem seem plausible. Noether’s theorem tells us that, for every continuous symmetry in nature, there is a conserved quantity. It’s so central to what follows that I think you have to have some confidence in the truth of the theorem. So that’s where I’ll begin.

Now we can examine the first of the four forces: gravity.

There’s a very nice demonstration of how curvature creates forces, and that I reference in the above video. You can see it on YouTube.

Finally, for those who want something a bit more detailed, I’ve put together a 10 minute summary of General Relativity. It took me several years to boil GR down to the absolute essentials so that I could remind myself, on a single sheet of paper, how it all hangs together. so here is the result.

Warning – this one, and the ones that follow, are all maths.

If you would like something a bit more leisurely, then the following video (not by me) does the same thing in about two hours (phew, what a slouch!).

And if you really want to learn GR, then Leonard Susskind’s videos can’t be beaten.

http://theoreticalminimum.com/courses/general-relativity/2012/fall

The only book on General Relativity that ever made the slightest bit of sense to me was this one. (And it makes a LOT of sense.)

Cheng: Relativity, Gravitation and Cosmology A Basic Introduction

One thought on “Four Forces – Gravity

  1. Only just got round to watching these two presentations (I haven’t looked at the third one!) I must admit that I hadn’t really thought about forces in terms of conserved quantities leading to local transformations – or, at least, if any of my physics teachers put it that way, I wasn’t paying attention. Looking forward to catching up with the electromagnetism one now!

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s