Detailed analysis now indicates that a tiny amount of this quasar 's light was absorbed by intervening ionized oxygen . Astronomers intuit that this oxygen is surely accompanied by much more abundant ionized hydrogen , which would otherwise be invisible. The oxygen is thus thought to be the tip of a tremendous iceberg , indicating a universe filled with proton and electron clouds so vast they likely exceed the mass of all the stars combined. Still, this is only a small part of the long-sought dark matter astronomers have been searching for. Our universe is thought to be filled with much more abundant, much stranger forms of dark matter .
Specific rights apply .