Einstein brilliantly wrote about the influence of gravitation on time in his article on General Relativity. Then came Emmy Noether’s theorem: Energy conservation demands a constancy of the constants of physics, like the speed of light: they must be invariant to time translations. She wrote to Einstein that his GR...

## The day Relativity changed

loopdoctorNovember 30November 300Level I Student, Level II Advanced, Level III Doctor

Einstein started publishing on his General Relativity in January-February 1916. On these articles Karl Schwarzschild based his exact solutions. On 11 May that year, however, Einstein published is official GR – with a little but important change: no more two equal reference frames. Too late for Karl. Other...

## Properties of a torus-shaped Black hole

loopdoctorOctober 31October 310Level II Advanced

The ‘photo’ of the black hole in M87 is already iconic. The ‘Event Horizon telescope’ gave us a valuable look on the enormous object. But what do we see?ETH think it is the accretion disk (sending radiowaves) around the event horizon of a singularity. This conflicts with physics, Karl Schwarzschild and Einstein...

## Hubble based distance ladder-advanced for all distances

loopdoctorOctober 22October 220Level II Advanced

The Hubble law is widely used as distance ladder. Edwin Hubble assumed that high redshifted galaxies was caused by their speed, which led to the expanding universe. He never imagined that a redshift of more than 1 would ever be measured. How about relativity: Doppler at ultra-high speeds and gravitation?A step...

Black Hole Singularities and Wormholes: Albert Einstein would have warned against them and Karl Schwarzschild would have corrected these ideas, caused by errors. This article explains extensively the history behind these errors and also how they must be repaired. It turns out that a so called Event horizon belongs in...

## Lorentz transformation or Minkowski formula?

loopdoctorFebruary 20February 200Level II Advanced

In his Theory of General Relativity, Einstein replaced the Lorentz transformation by the formula of his tutor Minkowski. What happens if we apply the Minkowski formula back into the Theory of Spécial Relativity? What are the differences? This article shows: the Minkowski’s formula doesn’t create the Twin- and Ehrenfest...

## Time and Repairing the Schwarzschild Solution

loopdoctorFebruary 18July 110Level II Advanced

In his theory of General Relativity, Einstein replaced the Lorentz transformation by the Minkowski formula. He also introduced the variable speed of light in gravitation. This is unnecessary and untenable: it is in conflict with Noether’s theorem on energy and momentum conservation. The authors use the ‘time’...

## Gravitation not acceleration influences the clock.

loopdoctorFebruary 15February 170Level II Advanced

How do you interpret the equivalence principle of gravity and acceleration? Einstein said: standing in a hypothetical closed elevator, you cannot determine whether you hang still and feel the effect of gravity of a planet nearby , or you feel the same effect caused by the elevator accelerating out in space. What...

## Shapiro annihilates Eddington’s “drop the suffix”

loopdoctorFebruary 11February 120Level II Advanced

Long after Einstein’s death, Shapiro sent a radar signal to Venus, in its position opposite of the sun, and half an hour later received it back. With this astonishing experiment he proved part of the delay (190 microsec) was caused by the gravitation of the sun. Eddington, expert in Einstein’s theory of General...

## Albert Einstein’s space-time and the speed of light

loopdoctorDecember 12March 11Level II Advanced

Albert Einstein (1879 – 1955) was a pioneer of space-time. In 1905, he published his theory of Special Relativity, in which he discovered the energy in mass (E = m.c^2) based on the constancy of the speed of light to all observers. He also introduced time dilation (time going slower at high speed), based on the...