The first law of thermodynamics states that the energy of the universe is constant, but the universe is constantly expanding, so how does the energy stay constant considering the expansion?

Question

I think this is physics based(?), but I thought of this question during my summer chemistry course, so I wasn’t sure of the flair.

In: Physics

Answer 1

From my understanding this law only applies to closed systems. Given that we know we don’t know everything about the totality of our universes energy system, dark matter and dark energy being two examples, we cannot evaluate wether or not it adheres to this principle of nature.