Newtonian gravity is not coherent with special relativity. Einstein was well aware about it and he had to invent General Relativity (GR). Armed with the equivalence principle, a mystery since ancient times of Galileo, the equivalence between inertial and gravitational … Continue reading

# Category Archives: Gravitational theories

Some fundamental mottos: Fundamental spacetime: no more? Fundamental spacetime falls: no more? Fundamentalness vs emergence(ness) is an old fight in Physics. Another typical mantra is not Shamballa but the old endless debate between what theory is fundamental (or basic) … Continue reading

I am going to review the powerful Cartan calculus of differential forms applied to differential geometry. In particular, I will derive the structure equations and the Bianchi identities. Yes! Firstly, in a 2-dim manifold, we and introduce the Cartan 1-forms … Continue reading

Flatland is a known popular story and book. I am going to review the Bohr model in Flatland and, then, I am going to strange fractional (or fractal) dimensions, i.e., we are going to travel to Fracland via Bohrlogy today … Continue reading

The 2012 found Higgs particle is special. The next generations of physicists and scientists, will likely build larger machines or colliders to study it precisely. The question is, of course, where is new physics, i.e., where is the new energy … Continue reading

Cosmology is facing again some troubles. Some estimations of the Hubble parameter differ up to four standard deviations from the accepted value. Even when a few km/s/Mpc are not quite a huge difference, it turns than they can provide anomalies … Continue reading

The spectrum of gravitational waves!!!!! Purely gravitational wave music! The blog post today will cover two topics from elementary viewpoints: falling into a non-rotating black hole and gravitational wave “music”, i.e., gravitational wave formulae! It is a hard equilibrium … Continue reading

What is dark energy? Where does it come from? Is it constant? Is it a quantum field? Is it vacuum energy? Nobody knows what is the 70% of the Universe! In the beginning of Physics as Science, Aristotle himself introduced … Continue reading

Hi, there. Today some retarded Pi-day celebration equations (there is a longer version of this, that I wish I could publish next year). Some numbers and estimates for pi-related equations: 1st. Hawking radiation temperature (Schwarzschild’s 4d black hole case). (1) … Continue reading

Hi, there! Today some Kepler third law stuff plus cosmic speed calculations and formulae. Cosmic speed sounds cool…But first… From High School, you surely calculated how fast is A PLANET moving around the sun (or any star, indeed). To simplify … Continue reading