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A great question. First--It isn't always constant. Light can travel slower than "c" ("the speed of light"). In a perfect vacuum light travels at "c". It's slower in glass, air, water, etc., light can even stop! But "c" is the upper speed limit. Second--Not only light but ANY disturbance in the universe has a speed limit of "c". Even the influence of gravity travels at the speed of light. Third--Einstein didn't just wake up one day with a good idea. The constancy of the speed of light (and relativity in general) explained many curious observations that had been made, and solved many physics problems. Fourth--There have been competing theories that allow a variable "c" but all the experiments indicate that it is indeed a constant value.
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Can the speed of light be changed?
no. speed of light is always constant . as long as the light stays in the same medium. the speed is generally slightly different in different media.
What is the average constant speed of light in vacuum?
The speed of light in vacuum is 299,792,458 meters per second, and that's not an average. That's what it always is.
What is the different between constant velocity and constant speed?
constant velocity is when you maintain speed and direction, this usually is in a straight line, and constant speed means that your speed is always constant at all times.
If a ferris wheel is rotating at constant speed is it moving at a constant velocity?
No. Velocity combines speed and the direction of motion.Constant velocity is constant speed in a straight line.In circular motion, the velocity is always changing even if the speed is constant,because the direction is always changing.
What does the speed of light equal in a vacuum?
The speed of light is a constant, C= 300,000 km per second.
