Eternal inflation

Eternal inflation is a theory that suggests the universe could be bigger than we think. It says that, a long time ago, pieces of the universe started growing really big really fast because of something called dark energy. This dark energy kept pushing outward and eventually it created pockets where even more dark energy was found. These pockets made the pieces of the universe grow even faster, and this process just keeps going and going. That means our universe is always expanding, and we could never measure how big it really is.