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.

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

Catherine Pepinster, professional Catholic

And in the Big News today from a Faith Perspective, happy eve of all Catholic martyrs day everybody!

Suicide attackers from certain other religions, no other religions in particular spring to mind here, are not proper martyrs. They’re just a bunch of religious fanatics. Proper martyrs are all Catholics.

Preposterously Reverend Lord Professor Bishop Baron Lord Richard Harries, Baron Pentregarth, Gresham Professor of Divinity, Baron, Bishop, Professor, Lord…

There’s an election in America. Christians invented democracy and accountability. We need this because we are basically bad, but with good bits that look like the Invisible Magic Friend.

No need to mention that we evolved to be a social species which creates tension between our altruistic and selfish natures. No, it’s all to do with invisible magic stuff.

Rev Lucy Winkett, Rector of St James Piccadilly, handy for Fortnum and Mason

The Invisible Magic Friend’s holy virus turns out to be even worse than we thought. There’s only one thing to do, keep believing in the Invisible Magic Friend. Pray to him to make his holy virus go away, or at the very least, just kill somebody else. It’s the only possible thing to do. You know it makes sense.