Definition

Noun: A theory in physics developed by Albert Einstein, which describes the relationship between space and time. It is based on two main principles: 1) The speed of light in a vacuum is constant and is the same for all observers, regardless of their motion or the motion of the light source. 2) The laws of physics are the same in all inertial frames of reference (non-accelerating systems).

Usage

This term is used specifically in the field of physics to refer to Einstein's 1905 theory, which deals with objects moving at constant, high speeds. It is often contrasted with "general relativity," which includes gravity and acceleration.

Examples

Advanced Usage

• "The principles of special relativity": Refers to the two foundational postulates of the theory.
  • The principles of special relativity lead to the conclusion that mass and energy are equivalent.
• "Within the framework of special relativity": Used to indicate an analysis or calculation done according to the rules of this theory.
  • Within the framework of special relativity, nothing can travel faster than light.

Variants and Related Words

• General relativity (n): Einstein's later theory that extends special relativity to include gravity and accelerated frames of reference.
• Relativity (n): The broader concept encompassing both special and general relativity.
• Relativistic (adj): Pertaining to or involving the theory of relativity, or describing speeds close to the speed of light.
  • Relativistic effects become significant at very high velocities.

Synonyms

• Einstein's special theory of relativity: The full formal name.
• Special theory of relativity: A common alternative phrasing.

Related Concepts and Phrases

• Time dilation: A consequence of special relativity where time passes slower for a moving object relative to a stationary observer.
• Length contraction: A consequence where the length of a moving object appears shorter in the direction of motion to a stationary observer.
• Mass-energy equivalence: Expressed by the famous equation E=mc², which is a result of special relativity.
• Inertial frame of reference: A key concept in the theory; a system in which an object not subject to forces moves at a constant velocity.

Noun

1. a physical theory of relativity based on the assumption that the speed of light in a vacuum is a constant and the assumption that the laws of physics are invariant in all inertial systems