Schwarzschild Radius: The Boundary of a Black Hole

The Schwarzschild radius is the critical radius at which the escape velocity from a massive object equals the speed of

Bending of Starlight: A Historic Test of General Relativity

One of the first major confirmations of Einstein’s general theory of relativity came from observing the bending of starlight during

Invariant Interval: The Unchanging Spacetime Distance Between Events

In special relativity, the invariant interval is a fundamental quantity that measures the “distance” between two events in spacetime. Unlike

Relativistic Mass-Energy Equivalence: Energy and Mass Are Interchangeable

The relativistic mass-energy equivalence is one of the most famous concepts in physics, captured by Einstein’s iconic idea that mass

Relativistic Beaming: Radiation Focused by High-Speed Motion

Relativistic beaming is a phenomenon in special relativity where radiation emitted by an object moving at speeds close to the

Lorentz Factor: The Key to Relativistic Effects

The Lorentz factor is a concept in special relativity that explains how measurements of time, length, and other physical quantities

Gravitational Time Dilation: Time Slows Down Near Massive Objects

Gravitational time dilation is a key prediction of Einstein’s general theory of relativity, which states that time passes more slowly

Twin Paradox: Resolved by Asymmetry in Acceleration

The twin paradox is a famous thought experiment in special relativity involving identical twins: one stays on Earth while the

Rapidity: A Relativistic Alternative to Velocity

In special relativity, rapidity is a mathematical quantity that replaces velocity to simplify the description of motion and transformations between

Proper Time: The Clock’s Time in Its Own Frame

In the theory of relativity, proper time is the time interval measured by a clock that is moving with the