Dark matter hunt: US LUX experiment reaches critical phase
7 April 2014 Last updated at 23:55 BST
The quest to find the most mysterious particles in the Universe is entering a critical phase, scientists say.
An experiment located in the bottom of a gold mine in South Dakota, US, could offer the best chance yet of detecting dark matter.
Scientists believe this substance makes up more than a quarter of the cosmos, yet no-one has ever seen it directly.
Early results from this detector, called LUX, confirmed it was the most powerful experiment of its kind.
Rebecca Morelle reports for Newsnight.