If anyone can invent a time machine, it's probably famed physicist Stephen Hawking. But the author of "A Brief History of Time" is, himself, running out of time. He's already 71 years old and almost completely paralyzed by amyotrophic lateral sclerosis (ALS). Those facts, however, won't stop Hawking from hosting a party for fellow time travelers. In fact, he already had the party – back in 2009.

The event, complete with caterers and champagne, was held at the University of Cambridge on June 28, 2009. No one showed up, of course, because Hawking didn't send out the invitations until this year. That way, only people from the future could even know about the event. But this week Hawking said he hopes that the guests who didn't show up in 2009 will still manage show up at some point in the future — or the past? — and therefore prove his theories about time travel.

By the way, you can get one of those invitations yourself right now, as long as you're willing to spend about $230. The invites have been printed as special letterpress posters, designed by artist Peter Dean, in a limited edition of 100 copies. They've been printed on handmade archival black paper with silver ink that should last pretty much forever. You can check it out below:

Stephen Hawking invitation to time travel

If that price is too steep for you, a less permanent version, screen-printed on orange paper, will set you back about $65.

Hawking said this week that he hopes copies of the poster "will survive for many thousands of years. Maybe one day someone living in the future will find the information and use a wormhole time machine to come back to my party, proving that time travel will, one day, be possible." (He did not say if he hopes any guests will arrive in a TARDIS.)

Dean, the designer, told The Telegraph this week that Hawking is happy with his work. "Prof. Hawking is a world-famous physicist, but he is not a great poster designer," he joked.

Hawking himself recorded this tongue-in-cheek invitation video, where he says he likes the simplicity of this experiment and counts down to the arrival of his possible guests:

Related on MNN: