Is time travel possible?

Surprising as it may sound, the laws of physics as we understand them today don’t prohibit time travel. The solutions to Einstein’s equations of general relativity include ‘closed timelike curves’, which would effectively allow you to travel back into your own past. Hawking was bothered by this because he felt that backward time travel raised logical paradoxes that shouldn’t be possible. He suggested that some currently unknown law of physics prevents closed timelike curves from occurring – his so-called ‘chronology protection conjecture’.