What if dark energy is weakening?

A pioneering cosmic-mapping project seems to show that dark energy could be getting weaker, with potential implications for theories of how the Universe has evolved and for what its future might hold. The mysterious force is like reverse gravity, pushing everything apart and causing the Universe to expand faster and faster, getting colder and emptier. Initial results from the Dark Energy Spectroscopic Instrument in Arizona hint that dark energy is not a constant after all, which means the Universe’s expansion could start to slow down. But researchers say that the evidence for changes in dark energy is still very uncertain.