## Background

The theory of relativity originated from Albert Einstein, first in 1905 with his paper on special relativity and then with his work on general relativity from 1907 to 1915. Relativity is a mathematical model that accurately describes the energy of matter, gravity and much more. **Some** of the strange concepts to arise out of relativity are:

- the notion of spacetime where three-dimensional space and time are merged together
- a speed limit that nothing can go faster than the speed of light
- the mass of an object increases as its speed increases – referred to as
*relativistic mass* - the length of an object decreases as its speed increases – referred to as
*length contraction* - the clock (time) of an object slows as its speed increases – referred to as
*time dilation*

Relativistic mass, length contraction and time dilation are hardly noticeable at low speeds, but at relativistic speeds closer to the speed of light, they become very apparent.

## Explanation

Most of the strange cases in relativity can be explained by the principle that longitudinal waves travel the universe and are reflected off particles (wave centers). An object, which consists of particles, experiences the Doppler effect. In the example below, the radar source on the left sees a different frequency/wavelength of waves when reflected off the moving plane.

**Doppler Effect on Wavelength – Object in Motion**

**Spacetime**

Longitudinal waves travel the universe in three spatial dimensions. The frequency of these waves is constant for an object at rest (note that transverse frequencies – photons – are variable). The longitudinal wave frequency was derived here. Time is integrated very much into space and in all of the equations, as it is longitudinal waves that travel a three-dimensional universe at a given frequency.

**Universal Speed Limit**

Waves travel the universe at a defined speed limit – the speed of light. The density property of the aether governs this speed, much like how the speed of sound has a limit based on the density of air. From a particle’s perspective, when it reflects a longitudinal wave, it reflects back at the same speed, regardless of motion. The wave has a speed limit.

**Relativistic Mass**

Due to the Doppler effect, the longitudinal wavelengths of a particle on the leading and lagging edges of a particle change. The particle’s wavelength is the geometric mean of these modified wavelengths due to motion. This was proven in energy wave theory with the natural inclusion of the Lorentz factor when deriving Einstein’s energy-momentum equation.

**Length Contraction**

The orbitals of atoms are calculated as the number of wavelengths where attractive and repelling forces are zero. Below is an illustration of an atom and where the electron may reside, at a specific number of wavelengths from the atom’s core. Whether stationary or in motion, the electron is always at the same specified number of wavelengths.

In the stationary atom, the electron is fixed at a distance X. For the purpose of illustration only, this is locked in at eight wavelengths from the proton (actual wavelength count from the proton to the electron would greatly exceed eight cycles). In the atom in motion, the electron is still locked in at eight wavelengths, but now at a distance Y, which is shorter than X. In fact, the proton itself is also smaller. This is because the wavelengths are now compressed due to the Doppler effect for the particle in motion.

The atom has been compressed in the direction of motion. Furthermore, all atoms in the molecules that make up the object traveling at high speeds are subject to the same compression. Thus the length of the object is contracting – only on the axis in the direction of travel – because the Doppler effect shortens the wavelengths that bring the atoms of the molecules closer together. This is length contraction at relativistic speeds.

**Time Dilation**

Time dilation was explained in the Time page. In short, time is based on the frequency of the longitudinal waves that a particle reflects. Like length contraction, it experiences the Doppler effect which changes the perception of frequency relative to the observer.