Illustration of Special relativity

1905 Special relativity

The book of science

Tom Sharp

Albert Einstein physics Illustration of Special relativity

Special relativity

All motion is relative except for the speed of light, which is constant for every observer no matter how fast the observer moves relative to the light emitter. As a body in motion approaches the speed of light its energy and therefore its mass approaches infinity. Thus Albert Einstein explained how Maxwell’s equations work for rigid bodies in motion. Essentially, physical laws are not changed by the motion of the framework in which they are tested.

Atomic bomb

In 1905, Einstein realized that E = mc2 —the energy of an object is equivalent to its mass multiplied by the square of the speed of light. In 1939, aware of Hitler’s efforts to build an atomic bomb, Einstein helped persuade President Roosevelt to push the U.S. to be the first to develop one. In 1950, Einstein analyzed the grave global risks of the nuclear arms race, and called for the “peaceful coexistence of nations.”


I lie under blankets, and my window is open to the night. A jet warbles through clouds in his southerly descent. A freight train comes closer from possibly any direction. Echos fail to distinguish north from south, east from west. The big world is flooded with air against my ears.

In his 1905 paper, “On the Electrodynamics of Moving Bodies,” Albert Einstein dealt with Michelson and Morley’s observation that no shift in the speed of light could be detected in any direction, even relative to the direction of earth’s rotation or orbit.

This was the third of four papers that Einstein published in 1905. The first helped begin quantum theory, “On a Heuristic Viewpoint Concerning the Production and Transformation of Light.” The second discussed Brownian motion and explained atomic theory, “On the Motion of Small Particles Suspended in a Stationary Liquid, as Required by the Molecular Kinetic Theory of Heat.” The fourth established the equivalence of matter and energy, E = mc2, “Does the Inertia of a Body Depend Upon Its Energy Content?”

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