# I am not able to understand the one-way speed of time

123 views

I am not able to understand the one-way speed of time

what it is

why scientists think like that

articles and research papers for further reading

In: 0

Do you mean the one way speed of light?

Einstein’s Theory of Special Relativity would be a good start. The “speed” of time for you, and the, “speed” of time for me would be different if we were traveling at vastly different velocities.

Also “time” here on Earth, and “time” on a planet, orbiting a star, in some distant galaxy thousands of light years away are different, as what happens in either system is in no way causaly linked to the other.

When it comes to the question you are asking, I don’t think there is a simplified version that would reflect on the reality. It’s just bloody complicated regardless.

Imagine that there are two photographs, one with an egg and another with a broken egg. If I asked you which photograph was taken first, you will say it was the one with the egg intact. The photo with the broken egg was taken later. This is because you intuitively understand that an intact egg can break, but a broken egg can never rejoin into an intact egg.

Why is this? The reason is that for an intact egg, there is a specific way in which all the molecules of the egg are arranged in space. Just one specific way to be in the ‘intact’ state.

On the other hand there are infinite number of ways for an egg to be broken. There are many many ways in which the pieces can be arranged such that the egg is in the ‘broken’ state.

So probability says that the chance that broken pieces will assemble into an intact egg is 1 in infinite…in other words 0%. The chance that intact egg will break eventually is infinity/infinity or 100%. Because of this, we say that the breaking of an egg is ’irreversible’. Now, there are many such irreversible things happening all around us…Everytime something like this happens, we know that time must have passed…there is a before state and an after state. This is the origin of ‘time’ and it happens in to go in one direction because probability makes some processes irreversible.

Scientists call this the second law of thermodynamics and the probability and chance part is defined in a quantity called entropy.

I just know that someone is going to bring up Einstein here. People very often confuse the arrow of time as coming from Einstein’s relativity. This is incorrect, as relativity does not say anything about the arrow of time. Einstein asks a very different question. He asks, if things keep changing irreversibly, what is the speed at which they change ? What is the *maximum* speed at which things *can* change ?

The answer is that the maximum speed is the speed of causality (more commonly known as the speed of light, because light moves at the maximum speed at which things can change). The later part of Einstein’s work shows the relation between the speed at which things change in time , and the speed at which they change in space (the total must always be equal to the speed of causality).