Time Travel Isn't Possible…Or Is It?

Paul Sutter is an astrophysicist at Ohio State University and Chief Scientist of COSI Science Center. Sutter is also a Spaceman, we asked Do not Planet, and now is host to COSI Science.

Special relativity teaches us that the three dimensions of the space and the single dimension of time are woven together like a fabric. It is impossible to think of them as separate agencies, except we are aware of speed through space-time only - a single unified entity - we can not think of the speed through space, and vice versa. On the left-right, up-down, back and all future side of the future.

And still, the time seems a little different. We have the final freedom of space space, but we can not avoid our future. While the time seems to have an "arrow", while the territorial dimensions are ambidextrous. Given the unity between time and space, it makes obvious questions: Time travel, any kind, possible? A good creator? At all?

In the future: Of course

Curiously, the answer is yes! We will not move towards our future, but we can control the time we are going to run. This is the result of relativity from another: All the clock is not the same.

The place you move to the speed determines the speed of time that you move in time. Short phrase: Moving watch run slower.

If you can build a large enough rocket (9.8 meters per second per second; acceleration by gravity of the earth beneath the same page), then constant acceleration of 1 GB (Do not ask about an engineering problem) You can reach the Milky Way galaxy - Your personal time is just for a few decades - a healthy 20,000 light years away -.

You can stop for a few hours, a picnic near the triangle A * (black hole in the center of the galaxy), and then your rocket can return back and return to Earth.

You will be eligible for the retirement time during the return, if the organization providing this facility is even closer, because when you travel only decades in accordance with your ship's clock, the earth will be accepted approximately 40,000 years.
Close the loop

Time is relative, but it is still flowing in the same direction for everyone. We are asked whether we can go in the opposite domain of general relativity (GR) domain - this is not only the mathematical understanding we use to understand mathematical language, but the full connection between the space time and the speed.

In Gry, we ask a little more technical question: like rotating time, like the timing of the rotation, or the existence of CTC has no mechanism to matter and the power (thing that spot time warps)? I know this phrase but it's a fun phrase to toss around the parties! "Curve" is a way here, "like time" means you do not go faster than the speed of light, and "stop" means it returns to its beginning - in other words, its own past

So, Einstein's Oracle has allowed CTC?

Yes!

Well ...

The possibilities are limited

There are about half a dozen familiar configurations about space-time, which allow CTC or past time to travel. For example, Goodle's incomplete theoretical fame, Cart Godell discovered that if the expansion of the universe (which it is) and the universe is rotating then CTCs will be allowed and we can travel in our imagination in a fantasy.

As much as I can say, Gödel used this solution to show Albert Einstein that there was probably no GR that it was a complete crack - I mean, let's not be skeptical of any self-reliant theory of the natural world, such as an obviously ridiculous solution?

But Gödel's point was distinguished - from all the observations it is understood that the universe is not spin, so that certain solutions are not applied to our universe, and in the past travel time is verboten

Ah! But what we did was to form an infinite long massive cylinder and it was set to spin on its axis around the speed of light. It will almost drag during the space, and some paths around that spinning cylinder will end in their own past. Good things have no infinite long wider cylinders in the universe, or we might have to think.

Wait, I got one: If you run into a wormhole (a shortcut in two remote locations during space) and a close light speed running around and bring it back, the usual time-reproduction effect will be one of the ends of others in the "future" , So you can sink directly through your animal's neck and finish it in the past. What is that Wormholes require the existence of "negative mass", and the negative mass does not exist in the universe? Well, hmm!
In the past: no

It is the same story every time (too much hard-to-forgive apologies). For each scenario, we allow CTCs in general relativity and our past travel time, nature find ways to confuse our plans and rule the scene.

What is happening? General relativity - principle - during travel in the past, but it seems to be ruled in every case. It seems that there are some fun waking, there must be some basic rules denied at the time travel. But there is not one. We can not point out any particle interaction at the datacent level, which clearly stops the formation of CTC.

Another indispensable law of the inevitable vivid nature of the past is similar: Entropy. That thermal power law goes into law that says that the closed system orders are disordered. (This law explains why an egg will not only read itself unscrew if you leave it alone enough). What time is associated with entropy? Maybe, but the subject of another article ....

"What time travel is possible?"