Light

[jaypee]

Can light travel through a vacuum? If so, can you provide an example.

thx.

[Mulder]

Have you ever seen the moon? [;)]

[LogicalAtheist]

Space is essentially a vaccuum. Furthermore, C is the speed of light in a vacuum, so how do you think we got that?!?

[dav2008]

Yeah, unlike most other waves, light doesnt need a medium to travel through..It was proposed that there was some medium called the ether, but I think experiments could not find conclusive evidence supporting it.

[FZ+]

And current theories of light as a group of mutually supporting electric and magnetic fields have made the ether rather pointless, as well as explained several other phenomenons....

[newton1]

light is a electromagnetic waves....
sure can through a vacuum

[Alexander]

No ethir means no difference for any experiment in moving vs non-moving with any velocity lab. So, h, c, G, e and all laws of nature shall not depend on lab's velocity. This in turn requires that h, c, G, e shall be invariant values (shall not depend on velocity of moving by them pobserver). This in turn requires space and time to be transformed very certain way (called Lorents transformations). Special relativity then precepitates from those transformations mathematically.

[Alexander]

No ether means no difference for any experiment in moving vs non-moving with any velocity lab. So, h, c, G, e and all laws of nature shall not depend on lab's velocity.

This in turn requires that h, c, G, e shall be invariant values (=shall have the SAME numerical values measured by DIFFERENT observers regardless their mutual motion). Say, observer moving with some velocity past electric charge shall measure same charge as non-moving observer. Or observer moving by flashlight shall measure same c as non-moving one.

This in turn requires space and time to be transformed very certain way between moving systems (called Lorents transformations).

Special relativity then precepitates from those transformations mathematically.