Question: Is it true that if you travelled at the speed of light, you wouldn't age?

Parnika Gupta answered on 6 Nov 2020:

Oh that’s great, so you know about the twin paradox. The twin paradox says that if one twin stays on Earth and the other goes to space, Einstein’s theory of special relativity says that time slows down or speeds up depending on how fast you move relative to something else. Approaching the speed of light, a person inside a spaceship would age much slower than his twin at home. It’s not that you would not age, it is just that you would age slower, because our bodies are not massless, so we actually cannot go at the speed of light, but astronauts do travel relatively faster than the normal speeds. when you think of speeds in space, always think of relative speed.
For example, a tortoise is slower than a rabbit, but it is faster than a snail. So think of the relative speed of the twin in space, it is much higher than that of the twin on earth, which makes time go differently for both. The faster you move through the three dimensions that define physical space, the more slowly you’re moving through the fourth dimension, time––at least relative to another object. Time is measured differently for the twin who moved through space and the twin who stayed on Earth. The clock in motion will tick more slowly than the clocks we’re watching on Earth. If you’re able to travel near the speed of light, the effects are much more pronounced.
It is a bit mind boggling but quite interesting. Read up more on the twin paradox if you are interested in it, it’s really cool!