What If You Built a Tipler Cylinder?

Are you ready for the trip of a lifetime? Because this not so little machine is about to take you on one. A trip back in time. What would you need for this time travel to happen? How would it mess with your body? And what do black holes have to do with all of this?

Theoretically, building a time traveling device is possible. Or almost possible. All you’d need to do is to assemble an enormous cylinder, and get yourself a spaceship. Then you’d need to figure out how to make the cylinder spin at a few billion rotations per minute. And remember I said it was enormous? Well, for this cylinder to work, its length would need to be infinite.

Before I get into the explanation of how this time machine works, let me give you a bit of a back story. In 1915, Albert Einstein came up with his theory of general relativity. He claimed our Universe can be described by four dimensions. The first three would be the dimensions of space, and the fourth would be time. Together, they’re space-time. Gravity can bend space-time like a bowling ball would bend a rubber sheet. The bending of space-time makes time slow down. The passage of time also changes depending on how fast you move.
The theory of general relativity blew people’s minds. But it was Frank Tipler who in 1974 realized that solutions to equations of general relativity could be used to build a time-traveling device.

Now that you’re all caught up, let’s start building this machine already. First, you’d need to find material with the total mass of about ten Suns. Where you’d find all that matter is a big question, of course. But let’s assume you managed to strip all the neighboring star systems and assemble them into a cylinder somewhere above the Earth. Ten solar masses worth of matter is no joke. It would take up a lot of space. And you would have to figure out how to compress all that matter. It would have to be so dense, that it would turn into an elongated black hole. There’s no time to worry about getting sucked into it. Now that you finally assembled a Tipler cylinder, you’d need to make it rotate at an unimaginably fast rate, a few billion times every minute.

Theoretically, instead of condensing a whole lot of matter into a black hole, and then having to deal with the cylinder rotation, you could just find a few neutron stars. Those are leftovers from gigantic stars that didn’t have enough mass to collapse into black holes. And they rotate pretty fast. You could line up a few of them and synchronize their rotation. But even if you chose the fastest ones, their rotation wouldn’t come close to a few billion times per minute.

Besides, in our earlier video, we already tried bringing a spoonful of neutron star back to Earth. And it didn’t go that well. Anyway, regardless of how you achieve this effect, the massive gravitational pull of the cylinder combined with the fast rotation would create a frame-dragging effect. In other words, the cylinder would drag space-time along with it.

That means that you could hop on a spacecraft and follow the spiral course of the cylinder. And that would take you back in time. Time would fold upon itself, and you’d find yourself in a closed timelike curve. It’s a loop, in which your traveling into the past has always been a part of that past. So you wouldn’t create any time paradoxes. If you changed the direction of your travel, you’d go back to the future. Or rather, back to the time you started your journey from. The Tipler cylinder’s specialty is travel into the past, not the future.

But hey, you could hang out with your favorite people from the past, go see a real-life Jurassic world. You could even go back to the time when the Earth didn’t have any life at all. But, of course, there’s a drawback. All that would only be possible if the Tipler cylinder had an infinite length. It would have to go on forever. But that’s just impossible. You can’t build something that has no end at all.

If you tried to make a finite cylinder, then you’d have to deal with some exotic matter and its negative energy. But we haven’t discovered it yet, and it doesn’t look like we’d be getting our hands on such matter any time soon. I haven’t even mentioned the effects of the black hole on your body. You’d instantly get sucked into the cylinder’s black hole if you got close enough.