Q:

What is the speed of light?

A:

Quick Answer

The speed of light in a vacuum is a universal constant, with a value of 299,792,458 meters per second. Nothing in the universe that has mass can, even theoretically, exceed this speed.

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Full Answer

The speed of light is so fast that it has become a convenient standard for measuring the vast distances in the solar system and beyond it. The distance between the Earth and the Moon, for example, is slightly less than 1 light-second. Light from the Sun takes 8 minutes to reach the Earth, and it takes around 1 hour to pass by the orbits of Jupiter and Saturn.

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Related Questions

  • Q:

    How fast is the speed of light?

    A:

    When light travels in a vacuum, its speed is 186,282 miles per second. The fastest aircraft, which is the Boeing-43 scramjet, has a speed of 7,546 miles per hour. If these two speeds are compared, the jet's speed is approximately 0.0004 percent that of light.

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  • Q:

    How fast do radio waves travel?

    A:

    Radio waves travel at a velocity that is equal to the speed of light traveling in a vacuum, which is 186,282 miles per second. Top speed is only possible in empty space; passing through transparent liquids and solids like crystals cause waves to bend, which slows down their speed.

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  • Q:

    How fast is lightspeed?

    A:

    Lightspeed, or the speed of light, is 186,282 miles per second in a vacuum. Traveling at this speed would allow a person to circle the earth at the equator approximately 7.5 times in one second.

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  • Q:

    What is the speed of light in water?

    A:

    The speed of light in water is approximately 225,000 km per second. While enormously fast, this is notably slower than the speed of light in a vacuum, which is 300,000 km per second.

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