# Category Archives: Relativity

Posts about relativity.

## Transformations between inertial systems of reference (download:-)

One can derive the Lorentz transformations without specific using the second postulate of relativity. You can find it in this document: Transformations between inertial systems of reference. Ok it is still a draft:-) Hope you enjoy it! Advertisements

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## Raising the power of a 2×2 matrix

The main question here is: given a matrix then what is ? Given is the matrix (1) . . . . It is clear that This can be written as . Note that and . We shall write and . … Continue reading

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## Neutrinos faster than light.

Recently experiment has shown that neutrinos move faster then light. Some claim that “neutrinos might break one of the most fundamental laws of physics”. The question would be “what law of physics would be broken?” In general this all is … Continue reading

Posted in Cosmology, Physics, Relativity, Special Relativity, Universe | 3 Comments

## Measuring the speed of light and the speed of the medium.

Let us consider a medium and an observer that is moving through that medium. Say that the magnitude of the velocity of light with respect to the medium is and say that the velocity of the observer with respect to … Continue reading

Posted in Mathematics, Physics, Relativity, Special Relativity | 1 Comment

## The escape velocity for the Schwarzschild metric (2).

In the other post The escape velocity for the Schwarzschild metric. we have found the escape velocity , however – this was based on the limit and . Let us return to the radial-equation for the Schwarzschild metric given by … Continue reading

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## Kerr metric and dragging.

The Kerr-metric is given by , where and . We solve the geodesic equation using It is clear that , then for we obtain the equation So there is a solution . Next we look to the equation for and … Continue reading

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## Solving the geodesic equation.

In this post, I will write about the geodesic equation. I suggest a simplified form that is simpler to solve. The geodesic equation is given by , where . We have used the convention that . Then we may write … Continue reading

Posted in General Relativity, Mathematics, Physics, Relativity | Leave a comment

## The escape velocity for the Schwarzschild metric.

The Schwarzschild metric is given by where and . The geodetic equation is given by The path for escaping is given by and , so we only need And we obtain the equations So Now it is clear that . … Continue reading

Posted in General Relativity, Mathematics, Physics, Relativity | 11 Comments

## The universe as a sphere.

Consider a uniform sphere that has mass and radius . The gravitational energy of an isotropic sphere is given by so using we obtain The energy is given by and defining we obtain where . So Using we can write … Continue reading

Posted in Cosmology, Mathematics, Physics, Relativity, Universe | 1 Comment

## Spontaneous creation of matter and antimatter.

In this post I will write something about the spontaneous creation of matter and antimatter. Let us consider matter as an elementairy particle. This elemenrairty particle has some mass and several quantum-numbers. We assume that charge itself is also a … Continue reading

Posted in Mathematics, Physics, Relativity, Special Relativity | 9 Comments