How long does it take to travel to the nearest star at the speed of light?

1 Answer
Oct 9, 2016

Approximately #4.2# years


The nearest star (apart from the Sun) is currently Proxima Centauri, which is about #4.2# light years away. (The Sun is a mere #500# light seconds or so from the Earth)

That means that the light we currently see from Proxima Centauri started its journey about #4.2# years ago.

If an astronaut were able to travel close to the speed of light, then from the perspective of observers at home, the journey would take at least #4.2# years.

Note however, that the astronaut would experience somewhat less time, depending on how close to the speed of light they were travelling.