LOG#189. Fundamental challenges.

The marriage between gravity and quantum mechanics is “complicated”. The best physicists and brightest minds have tried, but only with partial success. String/superstring theory, now M-theory, is a curious story. The another story is canonical quantum gravity, or loop quantum … Continue reading

LOG#150. Bohr and Doctor Who: A=mc³.

The year 2013 is coming to its end…And I have a final gift for you. An impossible post! This year was the Bohr model 100th anniversary. I have talked about this subject already, here, here and here. The hydrogen spectrum is very important in Astronomy, … Continue reading

LOG#105. Einstein’s equations.

In 1905,  one of Einstein’s achievements was to establish the theory of Special Relativity from 2 single postulates and correctly deduce their physical consequences (some of them time later).  The essence of Special Relativity, as we have seen, is that  … Continue reading

LOG#100. Crystalline relativity.

TABLE OF CONTENTS CENTENARY BLOG POST! And dedicatories… 1. Serendipitous thoughts about my 100th blog post 2. The search for unification and higher dimensional theories 3. Final relativity 4. Kalitzin’s metric: multitemporal relativity 5. Spacetime crystals and crystalline relativity: concepts … Continue reading

LOG#080. A Bug-Rivet “paradox”.

Imagine that an idealised bug of negligible dimensions is hiding at the end of a hole of length L. A rivet has a shaft length of . Clearly the bug is “safe” when the rivet head is flush to the … Continue reading

LOG#075. Batmobile “paradox”.

The Batmobile “fake paradox” helps us to understand Special Relativity a little bit. This problem consists in the next experiment: There are two observers. Alfred, the external observer, and Batman moving with his Batmobile. Now, we will suppose that the … Continue reading

LOG#056. Gravitational alpha(s).

The topic today is to review a beautiful paper and to discuss its relevance for theoretical physics. The paper is: Comment on the cosmological constant and a gravitational alpha by R.J.Adler. You can read it here: http://arxiv.org/abs/1110.3358 One of the … Continue reading

LOG#052. Chewbacca’s exam.

I found this fun (Spanish) exam about Special Relativity at a Spanish website: Solutions: 1) 2) 3) t=13.6 months = 13 months and 18 days. Calculations: 1) We use the relativistic addition of velocities rule. That is, where u=Millenium Falcon … Continue reading

LOG#049. Ludicrous speed.

We are going to learn about the different notions of velocity that the special theory of relativity provides. The special theory of relativity is a simple wonderful theory, but it comes with many misconceptions due to bad teaching/science divulgation. It … Continue reading