## Gravity unexpectedly popular, levity suspected

My “Not your grandfather’s gravity” talk proved unexpected popular: it was SRO & post talk I ran into four or five people who hadn’t been allowed in the room at all because of the fire regulations.

Pre-talk I ran into a lot of people fascinated with gravity, had lots of great conversations, & spent part of Saturday morning folding in some of the suggestions.

As I said at the talk, this provided a perfect example of how the Higgs boson gives particles mass via interactions. In principle, you could walk from one end of the hotel to the other in under five minutes. But in practice, with all the conversations, it could take three hours! Ditto the Higgs. The electron wants to just zip thru space, but it keeps interacting with Higgs particles & losing a bit of time with each interaction. From a distance, it looks as if the electron — massless tho it may have been at the start — has acquired mass.

Very enthusiastic crowd at the talk. When I pointed out that we owed the black plague three debts of gratitude because it:

- Paved the way for the industrial revolution by making serfs valuable (as there were many fewer).
- Gave the population of Europe significantly enhanced resistance to HIV.
- Gave Newton time to think about mathematics, light, & orbits: “All this was in the two plague years of 1665 and 1666, for in those days I was in my prime of age for invention, and minded mathematics and philosophy more than at any time since.”

the crowd gave a round of applause to the Black Plague! 🙂

Post talk I got a lot of positive feedback & may do the talk again. Because of the new material the last few slides were (more than a bit) rushed. To recap, the main new developments in gravity over the last two years or so are (obviously in my opinion):

- Verlinde’s “On the Origin of Gravity and the Laws of Newton” derives gravity from thermodynamics, letting us talk meaningfully about gravity even without a confirmed theory of quantum gravity.
- The universe is about 95% mysterious: The WMAP & other results about dark energy & dark matter are now very solid, letting us say that the universe is only 5% baryonic matter, stuff we know about, with 22% dark matter, & 73% dark energy!
- New telescopes & new kinds of telescopes are looking for neutrinos, antimatter, WIMPS & other candidate sources of dark matter, & gravitational radiation.
- The Large Hadron Collider is online, looking for the Higgs (widely thought responsible for giving particles mass) & anything that might out there, i.e. signs of Calabi-Yau dimensions.

I’ve uploaded the latest version of the talk as pdf, keynote, power point, & html. Given that I find there are new developments just out each time I work on this, by the time you read this, it will already be at least slightly behind the times! 🙂