[camle]

if they can make light travel backwards, can't they make a "dark bulb" for day sleepers? (I mean there are lots od DIM BULBS in congress...)

and if light can be made to go backwards, down't that mean it has mass? and doesn't that destroy the conservation of matter thoery that says that mass cannot be created nor destroyed since one can turn a light off and on?

[LuxMaker]

and if light can be made to go backwards, down't that mean it has mass? and doesn't that destroy the conservation of matter thoery that says that mass cannot be created nor destroyed since one can turn a light off and on?

First off, light does have mass.

Second the conservation of matter theory could easily be said to be a conservation of energy theory as well because E=MC². Energy and Mass are directly proportional to each other. When you turn a light on, nothing is created as electrons are used to generate photons (light) both of which are different kinds of energy.