Did gravity, the force that pins us to Earth's surface and holds stars together, just shift? Maybe, just maybe. The latest measurement of G, the so-called constant that puts a figure on the gravitational attraction between two objects, has come up higher than the current official value.
Measurements of G are notoriously unreliable, so the constant is in permanent flux and the official value is an average. However, the recent deviation is particularly puzzling, as it is at once starkly different to the official value and yet very similar to a measurement made back in 2001, not what you would expect if the discrepancy was due to random experimental errors.
It's possible that both experiments suffer from a hidden, persistent error, but the result is also prompting serious consideration of a weirder possibility: that G itself can change. That's a pretty radical option, but if correct, it would take us a step closer to tackling one very big mystery – dark energy, the unknown entity accelerating the expansion of the universe.
"If G has changed by this tiny amount then we would expect that G depends on a new field," says cosmologist Tony Padilla of the University of Nottingham, UK. "One could imagine a scenario in which this field plays a role in dark energy."To read more, click here.