Gravitational waves and the geometry of spacetime

When speaking of our universe, it's often said that "matter tells spacetime how to curve, and curved spacetime tells matter how to move." This is the essence of Albert Einstein's famous general theory of relativity, and describes ...

Physicists reach atomic-scale telegraphy with light

In the 1880s Heinrich Hertz discovered that a spark jumping between two pieces of metal emits a flash of light—rapidly oscillating electromagnetic waves—which can be picked up by an antenna. To honor his groundbreaking ...

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Electromagnetic radiation

Electromagnetic radiation (sometimes abbreviated EMR) is a ubiquitous phenomenon that takes the form of self-propagating waves in a vacuum or in matter. It consists of electric and magnetic field components which oscillate in phase perpendicular to each other and perpendicular to the direction of energy propagation. Electromagnetic radiation is classified into several types according to the frequency of its wave; these types include (in order of increasing frequency and decreasing wavelength): radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. A small and somewhat variable window of frequencies is sensed by the eyes of various organisms; this is what we call the visible spectrum, or light.

EM radiation carries energy and momentum that may be imparted to matter with which it interacts.

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