That rare physicist to make the pop-culture crossover (ever heard of Dirac?), Stephen Hawking is one of the most respected minds both within his field and among the public at large. This unique prominence lets him advance arguments so outlandish-seeming that few others could pull them off. Last week, he proposed that humans should abandon attempts to contact intelligent aliens, for fear of attack. On Monday in the Daily Mail (UK), Hawking seriously--and at a length of 3,000 words--outlines how to construct a time machine.

What Hawking Would Do With a Time Machine

If I had a time machine I'd visit Marilyn Monroe in her prime or drop in on Galileo as he turned his telescope to the heavens. Perhaps I'd even travel to the end of the universe to find out how our whole cosmic story ends.

Why Time Travel Is Not an Absurd Idea
The concept may be far-fetched, and the reality may be very different from this, but the idea itself is not so crazy.

Physicists have been thinking about tunnels in time too, but we come at it from a different angle. We wonder if portals to the past or the future could ever be possible within the laws of nature. As it turns out, we think they are. What's more, we've even given them a name: wormholes. ...

Given enough power and advanced technology, perhaps a giant wormhole could even be constructed in space. I'm not saying it can be done, but if it could be, it would be a truly remarkable device.

An Experiment Illustrating a Paradox of Time Travel
I like simple experiments, and champagne. So I've combined two of my favourite things to see if time travel from the future to the past is possible. Let's imagine I'm throwing a party, a welcome reception for future time travellers. But there's a twist. I'm not letting anyone know about it until after the party has happened...my time traveller guests should be arriving any moment now. Five, four, three, two, one. But as I say this, no one has arrived. What a shame. I was hoping at least a future Miss Universe was going to step through the door.

On the Impossibility of Time-Traveling to Shoot Your Past Self


I believe things can't make themselves impossible. If they could then there'd be nothing to stop the whole universe from descending into chaos. So I think something will always happen that prevents the paradox.

Why Hawking's Still Optimistic

But the story's not over yet. This doesn't make all time travel impossible. I do believe in time travel. Time travel to the future.