I’m really curious about how the universe’s expansion works and what keeps it going. A thought crossed my mind: could it be mainly because of the law of conservation of energy?
In: Planetary Science
Distances between groups of galaxies get larger. There is no deeper “how”, that’s just what happens. There is a bit more space between them than there was yesterday.
> And What keeps it expanding?
If there is no force on an object, it keeps moving in the same direction at the same speed. The expansion of the universe works pretty similarly. Without any force it would keep expanding in a constant way.
* Gravity slows the expansion. That was more important in the early universe when everything was closer together.
* Something we call dark energy speeds up the expansion. Today that is more important, which means the expansion speeds up a bit. It’s still slow on human timescales. Distances increase by ~1% every 140 million years.
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