Parallel universes are hypothetical universes that exist alongside our own.
They are also known as multiverses or quantum universes.
There are a number of different theories about how parallel universes could exist.
One theory is that they were created at the Big Bang.
There is no direct evidence to prove the existence of parallel universes, but there are a number of indirect pieces of evidence that suggest they could be real.
One of the most popular theories about parallel universes is the Many-Worlds interpretation of quantum mechanics.
According to the Many-Worlds interpretation, there are an infinite number of parallel universes, each with its own unique history.
Some universes may be very similar to our own, while others may be completely different.
Our universe is simply the one that is fine-tuned for life.