Your chemistry high school teacher lied to you when they told you that there was such a thing as a vacuum, that you could take space and move every particle out of it.
Adam RiessDark energy is incredibly strange, but actually it makes sense to me that it went unnoticed, because dark energy has no effect on daily life, or even inside our solar system.
Adam RiessUntil the 1990s, there were few reliable observations about movement at the scale of the entire universe, which is the only scale dark energy effects. So dark energy could not be seen until we could measure things very, very far away.
Adam Riess