But if dark energy is so hard to study, how did we stumble onto it in the first place?
What is Dark Energy?
The universe is expanding, and that expansion is accelerating. But what is causing that to happen? The leading hypothesis is a repellent force that astrophysicists refer to as “dark energy,” which pushes everything away from everything else. So how does it work? What does it mean for our future? And how sure are we that it even exists?