① Light is the fastest
② Light goes straight
③ Light is not heavy
④ Light travels even in vacuum
The speed with which the wave propagates increases as the volume of the medium changes.
Likewise, the smaller the density of the medium, the faster the speed.
In other words, the medium is strongest, lightest.
Those with straight traveling waves in the direction perpendicular to the axis.
That is, like a bow and arrow, like a trump skip.
We can not measure the weight of water in the water.
In other words, light is water and water is light.
Is it a wave propagating in nothing vacuum?
In other words, there is nothing vacuum.
The world made very tightly hard is fluidized with wave motion.
It is fluidized, but it keeps regularity and keeps changing.