Eminent physicist and cosmologist Dr. Stephen Hawking has recently come out to say that he no longer fears ridicule and endorses the possibility of time travel. While this might seem like a revelation, his actual endorsement is not. Let me explain.
Einstein’s Special Relativity has shown for nearly the last century that objects appear to move through time more slowly the faster they move through space. This phenomenon has been measured, though the effect is so slight in everyday experience that physicists ignore it. However, if astronauts were to travel in a spaceship very close to the speed of light, (a version of the Twin Paradox,) the effect would be very pronounced (see: Time Dilation), and our intrepid explorers would zoom forward in time – in a few years time spent away for the astronauts, the Earth and everyone on it will have aged centuries.
This is the only sort of time travel Dr. Hawking has come out to endorse – forward time travel as a result of moving quickly – which, as I mentioned above, has been a known effect for nearly a hundred years. Backward time travel in Dr. Hawking’s view is still impossible because it would allow violations of causality, which bother him. (Endorsing that kind of time travel would have truly been a revelation!)
So, nothing new here. However, anything that gets the physics of Relativity and time travel into public media is okay in my book!
…and being that Dr. Hawking is so clever, maybe that was his intent all along.
Astrowright 
I think its a bit of a cop out from Stephen really. It does seem like common sense that forward time travel is possible, given that we are already traveling in that direction anyway, but im not sure backwards time travel is impossible. Im sure eventually when we actually understand the fabric of the place we exist in we will have a much better idea of whether we can move back and forth in time.
Really nice blog by the way, I shall read some more.
Ste
Ste,
Thanks for reading! Yes, I agree that it was quite a cop out – but maybe he was being clever and using his celebrity to get talk of physics and time travel back into regular media. Or maybe not. But I also agree that we don’t understand enough to rule out reverse time travel. Hope you enjoy future posts!
Cheers,
Ben
[…] This summer, scientists at the Hong Kong University of Science and Technology announced that in a meticulous data transfer experiment, they verified that photons don’t break the lightspeed barrier, and their effects don’t appear to even slightly precede their cause. Hence, lightspeed is a barrier and causality is confirmed, thus ruling out backwards time travel. (On a side note, Stephen Hawking has also endorsed this view.) […]