Hints of quintessence point at dark energy

Cosmologists say that they have uncovered hints of intriguing twisting in the movement of ancient light across the Universe. The twisting was identified in the polarisation of the cosmic microwave background as observed by the Planck space telescope — but the evidence is still tentative. Some researchers have proposed that the twist is produced by a cosmic ‘quintessence’, an exotic substance that pervades the cosmos. The phenomenon could offer clues about the nature of dark energy — the mysterious force that seems to be pushing the cosmos to expand ever-faster. If dark energy is a quintessence, its push on the expansion could slowly wither or disappear, or could even reverse to become an attractive force, causing the Universe to collapse into a ‘big crunch’.