The concept of parallel universes, or multiverse theory, is a hypothesis in theoretical physics that suggests the existence of multiple universes that coexist alongside our own. While there is not yet solid empirical evidence to prove the existence of parallel universes, the idea is actively debated and explored in scientific research.

"Alongside" can be used as either a preposition or an adverb.

The destroyer rode up alongside the battleship to refuel.

Alongside Night was created on 1979-10-16.

A walkway found alongside a canal is called a tow path. Horses used to walk alongside it towing boats.