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

# Tag Archives: black holes

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

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

Black holes and other astrophysical objects are true monsters. Some interesting tools from web pages to learn about these free catalogues: WATCHDOG and BLACKCAT. Also, the blackhole.org page and the sounds of spacetime for gravitational waves are suitable for you. … Continue reading

Black holes are coming! No, winter is coming! NOOOO! Winter is here, and black holes, as shown by LIGO, are not coming. They are already here, as they were already supposed to exist due to X-ray astronomy. Moreover, LIGO-VIRGO, LISA, … Continue reading

The second and last blog post in this thread is about the analogies between black holes and condensed matter theory, in particular with phases of matter like fluids or superconductors. That is what explains my previous picture…And this post! Are … Continue reading

Hi, doctorish ladies and gentlemen! I am going to teach some bits of black hole today. For the simplest static (non-rotatory) black hole, the whole space-time is fully specified by mass , and some constants, like . The critical … Continue reading

Hello, metriplectic followers and friends! I have often written about Stoney units or Planck units in this blog. Indeed, I have a complete thread about systems of units. For Stoney and Planck units, you get some basic units of S.I. … Continue reading

This post continues the Bohrlogy thread I did some time ago. It aims to parallel electric Bohr (atom), the gravitational Bohr atom and the black hole atom (as new!). Note that , and , . First of all, the common … Continue reading

In this year, 2015, we celebrate the Light Of Year (LOY) and one century of general relativity (GR), a misnomer for something that should be called relativistic theory of gravity. Let me celebrate the centenary of general relativity with some … Continue reading