Maybe there’s a good reason why it has been so difficult to pin down the nature of dark energy – the mysterious force that is making the universe expand faster. Dark energy could be mediated by a chameleon-like particle that changes character to suit its surroundings.
Ever since dark energy was suggested in the late 1990s, cosmologists have struggled to explain just how it can counter gravity on the cosmological scale, but apparently leave it untouched here on Earth.
In 2003, Justin Khoury of the Perimeter Institute in Waterloo, Canada, and Amanda Weltman of the University of Cape Town in South…
