Can light travel as a longitudinal wave?

[k9b4]

If i have a charge in a vacuum, and I oscillate it at some frequency in x direction, other charges along the x direction will be caused to oscillate in the x direction.

So why was I always taught that the direction of oscillation is always perpendicular to the direction of travel for EM waves?

 

[NascentOxygen]

Charges in motion constitute an electric current.

 

[Dale]

If i have a charge in a vacuum, and I oscillate it at some frequency in x direction, other charges along the x direction will be caused to oscillate in the x direction.

So why was I always taught that the direction of oscillation is always perpendicular to the direction of travel for EM waves?

What you describe is only a near field effect, so it isn't properly an EM wave at all.

EM waves are transverse because they have two polarization states. If you wish to make an argument that they can be longitudinal also then you must show that they have 3 polarization states.