If dark energy is in fact weakening, it would likely mean that science's understanding of how the universe works will need to be rewritten.

And now scientists are getting a little closer to understanding how it behaves. The big question is whether this dark energy is a constant force, which scientists have long thought, or whether the force is weakening, a surprising wrinkle tentatively proposed last year.

A new map of cosmic expansion suggests that dark energy evolves over time, hinting that the universe doesn’t work the way we thought it did