Dark energy: Neutron stars will inform us if it's a delusion.

SISSA scientists provide the first simulation of neutron star collisions under cosmological extensions of general relativity, presenting a novel technique to testing gravity.

With Einstein's hypothesis, a massive amount of enigmatic dark energy is required to explain cosmic phenomena such as the rapid expansion of the Universe. But what if dark energy is an illusion, and general relativity must be altered?

A recent SISSA research published in Physical Review Letters takes a fresh look at the topic. Scientists constructed the first simulation yet of merging binary neutron stars in theories beyond general relativity that mimic a dark-energy-like behaviour on cosmic scales, thanks to massive computational and mathematical effort.

This allows for a comparison between Einstein's theory and updated versions of it, and with sufficiently exact data, it may be possible to answer the enigma of dark energy.