The universe has been expanding ever since the Big Bang almost 14 billion years ago, and astronomers believe a kind of invisible force called dark energy is making it accelerate faster.

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

New data involving millions of galaxies and luminous galactic cores is providing fresh evidence that the enigmatic and invisible cosmic force called dark energy - responsible for the universe's accelerated expansion - has weakened over time rather than remaining constant,