A smattering of missing matter
ScienceNOW: The heavens may be strewn with stars, galaxies, and nebulae, but the fact is astronomers don't know precisely where most of the ordinary matter in the universe is hiding. A new x-ray observation could help untangle that mystery: Astronomers have located a filament of hot gas stretching all the way from one cluster of galaxies to another. The filament is thought to be one thread in a vast web containing the missing ordinary matter, and, if confirmed, it could give scientists a better idea of where the rest of the stuff is lurking.
