Interplanetary space consists of a vaccum, what's the evidence that light waves can travel thru a vaccum?

The very fact that you can see other objects in space and space is vacuumed means light can travel under such circumstances.

The light from the sun's (and other stars) photosphere reach the Earth (and your eyes) after traveling through the vacuum of space and then through the atmosphere of the Earth into your pupils.

Look up at the sun... there's your proof

Your question is either very simplistic or very insightful...I will assume the latter.

This was an issue for two early scientist named Michelson and Morley. They set out some very famous experiments to look for the stuff light needed to travel on. They called it aether. The idea was, like going up or down stream in a river, light would travel faster going with the aether than against it. Well, as we all know by now, they found a rather amzaing thing,..light traveled at the same velocity no matter which direction the observer was traveling. There was no aeither was their conclusion.

Along came big Al (Einstein that is). He saw these results and explained the constant velocity of light (c) through his theories of relativity. What was happening, he posited, was that the measuring stick used to measure c was actually changing its length, depending on which way it pointed (into or with the direction of travel).

But all this hocus pocus failed to satisfy some physicists. They still looked for the thing light waves had to have to travel on. Wave have to have something to make the waves on...like water waves have to have, duh, water.

Along came quantum physics and. lo and behold, these unhappy physicists found that light is its own medium for making waves. Like the molecules of water in a pond, light is a particle and quantum of energy. And those quanta, taken as a group, form the waves, like the molecules of water form the ripples over the pond.

Bottom line, light travels in a vacuum (or less) because light is its own medium. The quanta form the waves as they speed through that vacuum (or less). In other words, light does need anything but itself to move on out.

We get sun rays through space isn't it??
Do we need more evidence?

Or are you starting the dispute of corpuscular theory v/s wave theory again?