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Light-year
A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in a vacuum in one year. While there is no authoritative decision on which year is ... > more -
Gravitational wave
In physics, in terms of a metric theory of gravitation, a gravitational wave is a fluctuation in the curvature of space-time which propagates as a wave, traveling outward from a moving object or ... > more -
Barred spiral galaxy
A barred spiral galaxy is a spiral galaxy with a band of bright stars emerging from the center and running across the middle of the ... > more -
Outer space
Outer space, also simply called space, refers to the relatively empty regions of the universe outside the atmospheres of celestial bodies. Outer space is used to distinguish it from airspace (and ... > more -
Ion thruster
An ion thruster (or ion drive), one of several types of spacecraft propulsion, uses beams of ions - electrically charged atoms or molecules - for propulsion. The precise method for accelerating the ... > more -
Luminosity
In general physics, luminosity (more properly called luminance) is the density of luminous intensity in a given ... > more -
General relativity
General relativity (GR) is the geometrical theory of gravitation published by Albert Einstein in 1915. It unifies special relativity and Sir Isaac Newton's law of universal gravitation with the ... > more -
Space suit
A space suit is a complex system of garments and equipment and environmental systems designed to keep a person alive and comfortable in the harsh environment of outer ... > more
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