Time can also be defined as the presence of motion and forces. These forces are caused by the expansion of space. The difference in speed between energy that can move at the speed of light and energy that can't is another factor that creates time.
The concept of time is also a natural reaction to the cognitive and evolutionary challenges that humans face. The amygdala, the region of the brain that makes memories, can also make time seem to move slower as more memories are formed.
Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart. One explanation for dark energy is that it is a property of space.
Dark force is a theory that suggests dark matter is made up of particles that interact with each other via a "dark force".
In physics, a four-dimensional (4D) shape contains time because time is considered the fourth dimension.
4D space is an extension of 3D space, allowing objects to move in more ways. Time is seen as a way for all dimensions to move forward. 4D describes how objects and environments change over time.
4D space combines three dimensions of space (length, height, and breadth) with one dimension of time to form a four-dimensional continuum. This continuum is called spacetime. Spacetime diagrams are useful for visualizing relativistic effects, such as how different observers perceive where and when events occur.