An Etymological Dictionary of Astronomy and Astrophysics
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Of, relating to, or subject to the theory of → general relativity.

→ general; → relativistic.

Not concerned with or based on the → theory of relativity. See also:
→ non-relativistic electron, → non-relativistic mechanics, → relativistic.

→ non-; → relativistic.

An electron that does not experience relativistic effects since its velocity is very small compared to that of light.

→ non-relativistic; → electron.

Mechanics in which the masses under consideration move at speeds much slower than the speed of light.

→ non-relativistic; → mechanics.

One consequence of the theory of → special relativity, according to which no two events separated by a distance greater than their separation in time multiplied by the → speed of light may have a → causal influence on each other. Violation of this principle leads to → paradoxes, such as that of an → effect preceding its → cause.

→ principle; → relativistic; → causality.

1) Physics: Relating to the → relativity theory.
2) Philosophy: Involving or characterized by → relativism.
See also:
→ non-relativistic, → relativistic aberration, → relativistic Doppler effect, → relativistic effect, → relativistic mass, → relativistic particle, → relativistic precession, → relativistic quantum mechanics, → relativistic redshift, → relativistic speed, → relativistic spin precession, → relativistic velocity, → ultrarelativistic, → ultrarelativistic gas.

From → relativist + → -ic.

The aberration of light for an object moving with → relativistic speed. In contrast to the classical case, the → Lorentz transformation between the → rest frame of the observer and that of the object must be used. Relativistic aberration is expressed by the equation: cos φ' = (cos φ - )/(1 - cos φ.v/c), where φ is the classical → aberration angle, v the speed of the Earth, and c the → speed of light. It can also be expressed as: tan φ' = -(c/v)(1 - v²/c)^1/2.

→ relativistic; → aberration.

The Doppler effect when the relative motion of the source and the observer is comparable to the speed of light. In that case the classical Doppler formula should be corrected for effects of the special theory of relativity (Lorentz transformation).

→ relativistic; → Doppler effect.

A physical phenomenon described only by the theories of → special relativity or → general relativity.

→ relativistic; → effect.

In → special relativity, the mass that is assigned to a body in motion. Einstein demonstrated that the velocity of the observer has an effect on the way inertial mass is measured. The relativistic mass is expressed by m_t = m₀ / [1 - (v/c)²]^1/2, where m₀ is the → rest mass, v is the velocity, and c the → velocity of light. The experimental evidence for this phenomenon is observed in the mass of high-speed electrons accelerated by magnetic fields. This formula shows that it is impossible for a mass to be accelerated to the velocity of light in a vacuum.

→ relativistic; → mass.

A particle which has a speed comparable to the velocity of light.

→ relativistic; → particle.

A → general relativistic phenomenon in which the line joining the → apsides of an orbit gradually rotates in a → prograde direction. Also called the → orbital precession and → perihelion precession. Although the general relativistic precession of Mercury's orbit is extremely small, the similar precession observed in the orbit of the → binary pulsar PSR B1913+16 amounts to 4.23 degrees per year, i.e. 36,000 times greater than the → advance of perihelion of Mercury.

→ relativistic; → precession.

A quantum theory that incorporates special relativity, for example, → quantum electrodynamics.

→ relativistic; → quantum mechanics.

A redshift caused by the → relativistic Doppler effect. → gravitational redshift.

→ relativistic; → redshift.

Same as → relativistic velocity.

→ relativistic; → speed.

The change in the direction of the → rotation axis of a → pulsar in a → binary pulsar. In such a system, → geodetic precession leads to a relativistic → spin-orbit coupling, analogous of → spin-orbit coupling in atomic physics. In consequence, the pulsar spin precesses about the total → angular momentum, changing the relative → orientation of the pulsar toward Earth (Damour & Ruffini, 1974). As a result, the angle between the pulsar → rotation axis and our → line of sight changes with time, so that different portions of the emission beam can be observed leading to changes in the measured pulse profile. In extreme cases, the precession may even move the beam out of our line of sight and the pulsar may disappear as predicted for PSR 1913+16 for the year 2025.

→ relativistic; → spin; → precession.

The velocity of a body when it is a significant fraction of the → speed of light.

→ relativistic; → velocity.

Of, relating to, or subject to the theory of → special relativity.

→ special; → relativistic.

Describing a system or situation for which the → Lorentz factor, γ, is much smaller than 1. See also → ultrarelativistic.

→ ultra- + → relativistic

Describing a system or situation for which the → Lorentz factor, γ, is much larger than 1. See also → subrelativistic.

→ ultra- + → relativistic