"Art Unwin" wrote in message
...
On Sep 16, 7:48 pm, Jim Kelley wrote:
Cecil Moore wrote:
Rectifier wrote:
Radiation has no mass ...

On the contrary, radiation is photons which indeed
do have mass when traveling at the speed of light,
which radiation does.

According to Einstein, anything with energy has mass equivalence -
especially photons. But other than that, nothing with mass can travel
at the speed of light. You can have one, or the other, not both.

73, ac6xg

True, travel is something less than the speed of light
Art

-

In what medium? Remember that the speed of light is different in different
media.