THOUGHT EXPERIMENT
Is Time Travel Possible?
Yes, but not in the way you might imagine
Time travel across physical space is possible. Time dilation due to relativistic mechanics has proven this as we travel closer to the speed of light, time moves slower in relation to the reference point of those at rest. If a spaceship were to travel one-half the speed of light and return to earth one year later, the astronauts aboard would find that more than one year has passed on earth when they returned. In essence, they have traveled into the future. Traveling to the past is another story. At least not without an infinite source of energy to warp space and time. In theory, if we were to exceed the speed of light, time will reverse, and it would be possible to travel back in time. There is a caveat. I propose we can send information from the past, and we can do it with current technology. Let me explain.
Consider the following thought experiment
The Time Capsule
What do we consider information? Suppose a person writes a note and places it into a box with only one slit. They cannot open the box until a certain date passes. Just imagine another box now with the same note within it. Anything written on the note is the same as the following box. We would agree that when we open box boxes at some point in the future, the note should read the same message that we wrote and deposited in each box. Now, consider a paired box that records information with quantum entangled particles. We code a message into these entangled atoms. The way we encode these particles are simple. We encode with Boolean values. 1 for a positive spin, 0 for a negative spin. We then place a recording device that will encode a message from measurements in the surroundings onto these entangled atoms. These recordings will be translated as time passes. When we open the time capsule, we should still expect the message to read the same. The message should read the same measurements.
Let’s now imagine if we take one of these paired boxes that take measurements. We also take aboard a box of messages that are not entangled. Now suppose someone takes a paired box with them on a ship traveling at near the speed of light. The note is written in entangled particles that we have entangled before we have set out on our spaceship. These two sister boxes each communicate to each other and auto-sync as the ship travels faster. In reference to the box at rest, the box on the ship takes measurements of some kind that can be held constant for both the box aboard the ship and the box on earth. Now, in relation to the box aboard the ship, time is traveling at a slower pace, than time on earth. This means that the box at earth is taking more measurements as time continues to progress. The astronauts when they deboard will find that the box to their surprise doesn’t have less because these particles have been entangled with each other. When they land, the astronauts would compare the list of measurements and find there are equal values to the entangled box, but unequal values to the box that is not entangled.
Now, let’s consider the reference point of the box that wasn’t aboard the ship.
When we look at the measurements of this box, we would find that there are more measurements than time has passed because of the entangled state of these particles. In essence, the ship on board the craft has communicated the future measurements that have to occur in real-time due to the entangled state.
It is a bit more complex than this thought experiment in practice, but work through the logic, you will see that receiving messages from the future is possible.
This is just a thought experiment. In practice, it’s a bit more nuanced.
