History of Light

	Revision 42 . . November 24, 2001 4:41 pm by Bignose [copyedit]
	Revision 41 . . (edit) November 24, 2001 4:12 pm by Koyaanis Qatsi
	Revision 40 . . November 24, 2001 4:08 pm by (logged).123.179.xxx [*Did a little copy editing, needs an english teacher to go over it for readability.]
	Revision 39 . . November 24, 2001 10:53 am by SJK [note value for c of 299,792,458 m/s is an exact value]
	Revision 38 . . (edit) November 10, 2001 2:46 pm by Xaonon

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Difference (from prior major revision) (no other diffs)

Changed: 8,10c8,10

According to standard modern physical theory, the speed of light propagation? (and all other electromagnetic radiation) in vacuum (notated as c) is a physical constant. Regardless of the [reference frame]? of an observer or the velocity of the object emitting the light, every observer will obtain the same value for the speed of light upon measurement.. c (exactly 299,792,458 metres per second, or about thirty centimetres in a nanosecond) is the maximal speed of any particle or information. This has been confirmed to a high degree of accuracy by experiment and observation in our "neighbourhood" (on a universal scale) in space and time .

According to standard modern physical theory, the speed of light propagation? (and all other electromagnetic radiation) in vacuum is a physical constant (notated as c). Regardless of the [reference frame]? of an observer or the velocity of the object emitting the light, every observer will obtain the same value for the speed of light upon measurement. c (exactly 299,792,458 metres per second, or about thirty centimetres in a nanosecond) is the maximal speed of any particle or information. This has been confirmed to a high degree of accuracy by experiment and observation in our "neighbourhood" (on a universal scale) in space and time .

Changed: 19c19

In passing through materials, light is slowed to less than c, by the ratio called the refractive index of the material. On the microscopic scale this is caused by continual absorption and re-emission of the photons that compose the light by the atoms or molecules through which it is passing.

In passing through materials, light is slowed to less than c, by the ratio called the refractive index of the material. On the microscopic scale this is caused by continual absorption and re-emission of the photons that compose the light by the atoms or molecules through which it is passing.

Changed: 23c23

The speed of light may also appear to be exceeded in some phenomena involving [evanescent waves]?. Again, it is not possible that information is transmited faster than c.

The speed of light may also appear to be exceeded in some phenomena involving [evanescent waves]?. Again, it is not possible that information is transmited faster than c.

Changed: 25c25

Help, real physicists, please give a better explanation!

Help, real physicists, please give a better explanation!