STEPHEN HAWKING ONCE THREW A PARTY FOR TIME TRAVELERS

IF YOU WANT TO ATTEND STEPHEN HAWKING’S INFAMOUS COCKTAIL PARTY, YOU’D BETTER FIGURE OUT HOW TIME TRAVEL WORKS FOR A JOURNEY BACK TO 2009.

HEY EVERYONE, Stephen Hawking is throwing a party, and we’re all invited! One catch: Hawking has been dead since 2018, and the party was in 2009. Still, the invitation stands.

What if you threw a party and nobody came, but that’s exactly what you expected? That’s precisely what famed astrophysicist Stephen Hawking did on June 28, 2009. He rented a space at Cambridge University and got balloons, decorations, and, yes, champagne. Then he sat in the empty room for a few hours and left.

Only then did he send out the invitation.

ESSENTIALLY, Hawking’s time travel party was held for our future descendants, should they ever crack the mystery of time travel, one of the biggest puzzles faced by modern physics.

The setup may seem silly, but Hawking was actually experimenting. That’s because our current knowledge of physics does not strictly forbid time travel. Indeed, in some cases, it’s explicitly allowed. Take the general theory of relativity, for example. This theory provides our modern understanding of gravity as the bending and curving of space and time in response to the presence of matter and energy, with that curving dictating the motion of matter.

General relativity provides several scenarios that enable time travel into the past. One involves an infinitely long cylinder, which rotates fast enough to allow you to travel a corkscrew path around it and end up in the past. Another is the creation of a wormhole where the ends are not synchronized to the same time, allowing you to travel down one end and exit into the past.

Every time scientists try to concoct a permissible time travel setup in general relativity, they encounter some random rule of the universe preventing them from realizing it. And yet, no hard-and-fast rule outright forbids time travel, so we’re a bit stuck. Hawking, like many other physicists, believed that a resolution to the dilemma would come in the form of an advanced theory of gravity, one we currently do not yet know.

SINCE NOBODY showed up to Hawking’s time travel party, we have a few possible conclusions:

1

Time travel into the past is not allowed. Our future descendants will realize a deeper understanding of the laws of physics and, in that deeper understanding, discover the fundamental reason why time travel into the past is forbidden. They will read about Hawking’s invitation and sigh regretfully that they could not make it.

2

Time travel into the past is allowed, but we figure it out so far into the future that Hawking’s invitation is lost in the historical record. Maybe some ancient Sumerian philosopher also hosted a time travelers’ party thousands of years ago, writing down the invitation on clay tablets spread throughout the land, but none of them survived to the present day.

3

Time travel into the past is allowed, but we never figure it out. Maybe humanity destroys itself. Maybe our human intellect isn’t quite powerful enough to discern the deeper mysteries of the universe, or we never bother taking a deeper look.

4

Time travel into the past is allowed, but there are rules. Maybe it’s exceptionally complicated or energy-intensive to build a time machine, or we can send fleeting signals into the past, but not entire persons. Or perhaps you can only travel as far back as the creation of the time machine itself.

Of course, if someone from the future had shown up, it would’ve been a big deal. But, as experiments go, Hawking’s party wasn’t a total bust. In this case, it showed that the mystery of time travel will remain unsolved — at least, for the time being.