Astronomers may have found some of the matter that has been missing from the universe, new research suggests.
Scientists have long puzzled over why the amount of matter they can see -- in the form of luminous stars, galaxies and so forth -- doesn't seem to be enough to account for the huge gravitational attraction that keeps those galaxies from flying apart.
Thus researchers believe that as much as 90 percent of the universe may be made of "dark matter" that nobody can see.
The big mystery has been, what would dark matter be made of?
Now, researchers from the Johns Hopkins University suggest that at least a small part can be accounted for by hydrogen and helium gas that is spread smoothly through intergalactic space.
This gas, formed billions of years ago just after the birth of the universe, is now barely detectable. Astrophysicists Arthur Davidsen and HongGuang Bi detected the traces of this gas by analyzing observations taken by other astronomers during the past 20 years.
They concluded that the gas can account for the missing dark matter that is "baryonic," or made of ordinary matter.
But the work still doesn't resolve what the vast majority of dark matter is made of; astronomers think this must be composed of some kind of exotic, unknown particle.
The work was published in the April 20 issue of the Astrophysical Journal.
Pub Date: 4/29/97