Here's why:
* Cathode rays are streams of electrons. Electrons are charged particles with mass.
* The speed of light is the fastest speed anything can travel in a vacuum. It's a fundamental constant of the universe.
* Cathode rays are accelerated by electric fields. While they can reach very high speeds, they are still significantly slower than the speed of light.
Typical speeds of cathode rays range from a few percent to a few tens of percent of the speed of light. This is still incredibly fast by everyday standards, but it's a far cry from the speed of light.
Think of it this way: Imagine a car traveling at 100 miles per hour. That's very fast, but it's still far slower than the speed of light, which is roughly 670,616,629 miles per hour.
