Dennis Overbye: Results from an assortment of experiments suggests to some that humans are getting signals from dark matter, the quarter of the universe that remains unseen.
'With so many experiments, we will soon know so much more about all of this,' [one scientist said.] 'In a year or two, we’ll either not be talking about this idea at all, or it will be all we’re talking about.'
Together with dark energy, dark matter constitutes 75 percent or more of the energy mass of the universe. We're not at all certain just what that stuff is.
Wikipedia: dark matter