2007-04-24 09:13:47 · 8 answers · asked by Jared M 1 in Science & Mathematics ➔ Physics
It depends on what kind of vacuum. Hoover is much faster than westinghouse. Generally, the noisiness of the vacuum is proportional to the inverse square of the light speed in it. Dogs can detect this relativistic effect of the light speed changing and tend to get very upset by it, because they are very attached to regular old Newtonian mechanics.
2007-04-24 09:24:26 · answer #1 · answered by Anonymous · 0⤊ 1⤋
Air has a refractive index slightly above 1 and thus the velocity of light in vacuum is a little more than the veocity of light in the atmosphere at the sea level which keeps changing. For all practical purpose, this difference is negligible.
2007-04-24 16:20:07 · answer #2 · answered by Swamy 7 · 3⤊ 0⤋
They are different speeds, the speed of light on Earth is 3.00 x 10^8 m/s, speed in a vacuum is different.
2007-04-24 16:17:51 · answer #3 · answered by Matt C 2 · 1⤊ 1⤋
Light WILL travel slower through different materials like glass, air, etc. The whole idea of a refraction index is the comparison between the accepted value of c (the speed of light) and the speed it travels through a clear medium like plastic, air, glass, water.
2007-04-24 16:21:04 · answer #4 · answered by zombiehive 4 · 2⤊ 0⤋
If by "on Earth" you mean through the air, then it's about 0.03% slower than it is in a vacuum. This is because at normal atmospheric pressure and temperature, the refractive index of air is about 1.0003. To get the percent change, subtract "1" from that number to get 0.0003 or 0.03%.
2007-04-24 17:43:57 · answer #5 · answered by genericman1998 5 · 0⤊ 0⤋
It depends on the density of the air at the point of measurement.
The speed of light is a constant in vacuum, but due to refraction, it will be traveling at a different rate depending on the air density through which it has passed.
Sorry about the hip-shot "constant" answer ... but thanks for making me think.
2007-04-24 16:16:45 · answer #6 · answered by Grendle 6 · 1⤊ 1⤋
The speed of light on earth is affected by gravity while in a vacuum it is not.
2007-04-24 16:18:00 · answer #7 · answered by Jimmy H 1 · 0⤊ 3⤋
Nothing, because the measured speed in a vaccum was measured on the earths surface, so it is relative to earth as the common field.
2007-04-24 16:24:41 · answer #8 · answered by rich c 3 · 0⤊ 1⤋