In the cosmos, time is not a constant aspect. However, your experience of time is typically quite stable, which is why it appears to you to be a constant. Your experience of time would be how it is now if you were traveling at near the speed of light. Time would appear to be running out for you, but for everyone else on Earth it would still be just a few seconds since you last emailed them or something similar.
Time goes by more quickly as you approach the speed of light, and less quickly when you're moving away from it. But even when you're not moving at all, time passes for everyone else on Earth anyway. A minute passes for you every second, but also every second a minute has passed for someone on the other side of the planet who isn't here today because they're away on holiday or something similar.
Now, if we go back in time, then time itself hasn't yet happened, so nothing can run out or pass away. But once we arrive at a certain point in the past, we find ourselves in a world that no longer exists. There's nothing after this point in time, so anything that existed before it no longer does so.
So time is relative to where you are in relation to the future and the past.
Recognizing time While most people consider time to be a constant, physicist Albert Einstein demonstrated that time is an illusion; it is relative and may change for various observers based on your movement through space. For example, if you are standing still on Earth while watching the sun rise, it will appear to move away from you. Because you are not moving towards it, there is no signal to tell you when it has fully risen; instead, you have to wait until it reaches its highest point before going outside.
This means that someone standing on Earth who is facing the sun when it first rises will see it set later than someone who is observing from somewhere else on the planet. As you travel west across the globe, the sun will seem to go down later because you are traveling into the shadow of Earth. Since there is no way to signal the rising and setting of the moon, this body also has to be waited upon to know when it is best to go outdoors.
Time passes more quickly as you approach the center of Earth because objects near the ground take longer to pass by. This is why astronauts aboard spacecraft experience time passing faster when they are in orbit around Earth or beyond. As they get farther away from our planet's surface, each day seems like a month to them (because one month equals a little over seven days).
While most people consider time to be a constant, physicist Albert Einstein demonstrated that time is an illusion; it is relative—it varies for various observers based on your movement through space. Even though time generally just flows forward, it supplies additional coordinate - direction. Thus, time can be thought of as a fourth dimension.
Einstein's theory of relativity explains how different observers moving at a constant speed with respect to one another will all assign different lengths to the same event.
For example, suppose Observer A is traveling toward Earth at 10,000 miles per hour while Observer B is standing still on Earth. According to Observer A, it takes 11 minutes for a message to reach Earth; according to Observer B, it takes 9 minutes. Since both observers are moving with respect to one another, they assign different lengths to their measurement of time.
This means that time is not constant; instead, its rate of flow is relative to the motion of the observer. An object moving with respect to you will appear to move more slowly than you. An object at rest with respect to you will appear to stop time completely.
This has profound implications for humanity's understanding of reality and our place in the universe. It means that there is no such thing as absolute truth, only perspectives based on one's location in space-time.
The short answer is no. Time may flow at various rates throughout the cosmos, yet all of these rates remain relative to one another. So, while time is a constant theoretically, the rate at which it passes is relative and is primarily controlled by gravity and speed.
In general relativity, time is considered to be an aspect of space-time that measures how much progress has been made across the universe. At any given moment, time exists but it does not matter; what matters is how much time has passed since you or I was born.
As far as we can tell, time moves at the same rate everywhere in the universe. However, this doesn't mean that it must do so; perhaps some places are experiencing a fast rate of time travel while others are stuck in slow motion. Or perhaps time travels more quickly near black holes because they force us to move faster too. We have no way of knowing unless we go there ourselves!
It's also possible that different parts of the universe are moving at different rates. This would explain why objects in our galaxy appear to move with respect to each other. They're actually standing still though, it's just that everything else in the universe is flying by them. If one part of the universe is rushing toward a massive object such as a star, then it makes sense that objects closer to the mass source would experience greater rates of time dilation than those farther away.