suppose two rockets with a passenger are nearing speed of light velocities and are going opposite directions. Relative to eachother one rocket will seem stationary while the other rocket will look like it’s going almost twice the speed of light. What do both passengers see?

Question

I can’t wrap my head around it. But maybe it might be a very silly question with a simple answer.

In: Physics

Answer 1

It won’t be going twice the speed of light or anywhere near it. It will still be less than the speed of light.

The way we think speed adds together isn’t really true.

In school we are taught that if we add 10 mph + 10 mph we get 20 mph.

However that is not true.

The truth is that the real way to calculate this is far more complicated than that.

At low velocities the truth is close enough that it makes no difference.

The close we get to the speed of light the more difference it makes.

90% of the speed of light + 90% of the speed of light is not 180% of the speed of light but something closer to 99.5% of the speed of light.

No matter how fast two objects move away from each other from the point of view of the object it will never be faster than the speed of light.

Additionally a flashlight shining out of a spaceship will emit light going at the speed of light in all directions and that will be true no matter which point of view you look at it from.

Velocity does not work at all the way we normally think of it.