3 ms·

Here's another way to think about this: Your velocity is time dependent quantity. When you are moving faster time for you is simultaneously slowing down. When y

Here's another way to think about this: Your velocity is time dependent quantity. When you are moving faster time for you is simultaneously slowing down. When you almost approach speed of light relative to anything, time for you slows down to almost zero relative to that thing. So everything runs in super slow motion. Another particle coming at you at the speed of light towards you will appear almost still. So you total relative velocity wrt to other particle is still just speed of light. The key is again, its because time has slowed down for you.

gus_massa 8y ago
This comment is confusing/wrong. > time for you slows down to almost zero relative to that thing This is at least confusing. You would not fell anything special. If all the windows are covered, you will not note that you are moving fast or slow. > Another particle coming at you at [almost] the speed of light towards you will appear almost still. If you are moving at a speed of 99% of c in the "laboratory" reference frame, and the other particle is still in the in the "laboratory" reference frame, then (if the front windshield is not covered) you will see that the other particle comes to you at a speed of 99% of c. If you are moving at a speed of 99% of c in the "laboratory" reference frame, and the other particle is moving in the oposite direction in the in the "laboratory" reference frame, then (if the front windshield is not covered) you will see that the other particle comes to you at a speed of 99.995% of c. (See the calculation details in the article.)