Is dark energy getting weaker?

Fresh data have backed up the discovery that dark energy — the mysterious force that makes galaxies accelerate away from each other — has weakened over billions of years. Until last year, all findings were consistent with dark energy being a ‘cosmological constant’, meaning that the Universe should continue to expand at an increasingly fast rate. The new findings show that the amount of dark energy per cubic metre of space is now around 10% lower than it was 4.5 billion years ago, which means that cosmic expansion is now accelerating less.