We understand time as unidirectional, meaning that we grow older, have memories of the past, and have no idea what the future will be like. However, there is no physical law that confirms that time only moves forward, but some believe that time actually moves in two directions.
Physicists are still working hard to prove this and the concept of time is subjective for humans, and they only approach it in a way that assumes the Earth is flat. Many physicists have studied this issue and sought to question it, verifying or refuting the idea that time "progresses" in one direction.
Many have relied on the concept of entropy, the degree of molecular disorder in a system, to explain the flow or passage of time. While physicists work in two distinct groups to establish the origin of this direction of time, they all converge on the same idea: that time actually flows in two directions.
To understand this, it is necessary to go back to the Big Bang, which caused the universe to come into being approximately 14 billion years ago. According to specialist scientists, this explosion created a mirror universe, where time flows in the opposite direction. However, from our perspective as humans, time in this parallel universe runs backward, meaning that the concept of time is running backward.
I have read about the first model presenting this theory was published a year ago in the journal Physical Review Letters. The model states that one of the fundamental principles of Newton's law of gravity created the unidirectional flow of time. The proponents of this hypothesis are physicists Julian Barbour, Koslowski, and Mercati, researchers at the University of Oxford, the University of New Brunswick, and the Perimeter Institute for Theoretical Physics.
They believe that in any system of particles (an independent universe like ours, for example), gravity creates a starting point where the distance between the particles is minimal. That is, when particles move apart, they do so in two different time directions. If this theory is correct, there is another universe on the other side of the Big Bang, where time flows in the opposite direction to ours.
However, physicist Mercati believes that such systems inevitably converge and tend to deviate from the second principle of thermodynamics, which establishes the irreversibility of physical phenomena and enters the aforementioned state of entropy so Mercati also adds that this initial disorder determines our individual perception of the direction of time.
