## Tags » General Relativity

#### Gravity 9: The Evolving Universe

by Shane L. Larson

Of all the fundamental forces in Nature, gravity is the weakest. What do we mean by that? Let’s forego our usual thought experiments, and do something real to demonstrate this idea. 2,232 more words

#### Astronaut Scott Kelly will return from a year in space both older and younger than his twin brother

Today NASA’s Scott Kelly, along with two Russian cosmonauts, blasts off for the International Space Station (ISS), where they plan to spend 342 days. Kelly’s identical twin brother Mark, also a (retired) astronaut, will stay on Earth to serve as the other half of… 485 more words

#### Closure constraints for hyperbolic tetrahedra by Charles and Livine

This week I been continuing to look at non-euclidean tetrahedra as in the post:

In particular I have been looking the paper ‘Closure constraints for hyperbolic tetrahedra’ in this paper the authors investigate the generalization of… 608 more words

#### And now for something completely different…

Each and every trade has its favourite tools, some more powerful than others. A plumber would not get by without a good wrench, a carpenter needs a hammer, a mechanic a screwdriver and so on. 748 more words

#### Update on my notes on General Relativity and GR (Gravity Notes) pdf, tex, sage math files update

Implementation of sphere S2 as a manifold in sage Math sage manifolds

### Postface

I write notes and code and make calculations for physics. 132 more words