Astronomers have completed the largest and most detailed study of what triggers a star birth in the universe’s biggest galaxies, using NASA’s Chandra X-ray Observatory and other telescopes.
"Until 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
“The mind, once expanded to the dimensions of larger ideas, never returns to its original size.” -Oliver Wendell Holmes
But it isn't just your mind that expands as time goes on and you increase your knowledge, but the entire Universe as well. General Relativity, as it turns out, doesn't leave us with much of a choice. If you start with a Universe full of matter and radiation, it's got to expand, otherwise it will collapse in on itself!