The universe is thought to be composed of stuff, non-stuff and maybe some other stuff. We're referring, of course, to matter, anti-matter and as-yet illusive dark matter. While we know a fair amount about matter and its opposite, dark matter is still largely theoretical. That might change in around half an hour, though, as folks from NASA, MIT and the US Department of Energy hold a press conference to explain exactly what the Alpha Magnetic Spectrometer (AMS) strapped to the