WITH reference Paul Brazier’s letter (Gazette 18/10/2018).

Time travel may be possible, as Steven Hawking has stated, but only in one direction, forward, you cannot go backward in time - this is known as the Arrow of Time.

As Hawking knew this comes from Einstein’s special theory of relativity (I have the translation of the original text in German, I have also read some of the original text) that you cannot travel any faster than the speed of light (sorry Captain Kirk your just fiction so you can just warp off).

Thus if we sent a manned spaceship into space and it travelled at 99.99 percent of the speed of light and returned 500 earth years later the crew of the space ship would only be 7 years older.

This phenomenon is known as 'time dilation’ from the theory of relativity.

Thus the crew would time travelled 500 years into the future but the crew cannot return to the earth time at the start of their journey plus 7 years (Time’s Arrow).

I hope this clears up confusion. See you in time and space!

Michael Boulton

Thornbury