We can see only 4% of the observable universe – the rest is made up of invisible ‘dark matter’ and ‘dark energy’. Now scientists are looking for a postulated force of nature that could open a door to the dark side. Ian Sample investigates

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We can see only 4% of the observable universe – the rest is made up of invisible ‘dark matter’ and ‘dark energy’. Scientists have been trying to understand this hidden realm for decades but are none the wiser.

This month, an experiment called Padme is being switched on to hunt for a previously undetected and so far only postulated force of nature. If found, it could act as a portal to the dark side: a means for physicists to get their first glimpse of what the invisible world is made from.

Ian Sample investigates all things dark with UCL’s Andrew Pontzen and the University of Illinois’ Jessie Shelton and asks: what could be on the other side?