Has the universe's missing mass been found?

In the above item, an article from Mosaic was quoted to the effect that 90% of the universe is "unseen." In pursuit of this missing mass, a U.S. team of astronomers has now detected previously unseen halos around several spiral galaxies. The halo luminosities are comparable to the brighter imbedded disks when integrated over a large area surrounding the galaxies. The halo masses, however, as inferred from the galaxies' rotation curves far exceed the masses of the bright spiral cores.

The big question is "What are the dim but massive halos composed of?" They might consist of small, faint stars or nonluminous matter of some sort. The researchers had to conclude, though, that the halos are galactic components of "totally unknown nature."

(Anonymous; "Has the Universe's Missing Mass Been Found?" New Scientist, 80:174, 1978.)