Word: quasars
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Dates: during 1990-1999
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...ordinary cosmic bodies in its celestial neighborhood. But this pinpoint of light is anything but ordinary. Spotted more than three years ago, it seemed at first to be a garden-variety star--but it wasn't. It might have turned out to be an unremarkable galaxy or quasar--but it didn't. Frustrated in their attempts to learn its nature, and even its distance from Earth, astronomers have begun to refer to the mystery object as, well, the "mystery object...
Bahcall has used the telescope to take pictures of quasars, starlike objects so bright they can be seen halfway across the universe. Most theorists think quasars are intimately related to giant black holes like the one Ford found; presumably their intense light comes from gas compressed with such force that it explodes in bright bursts of energy. That implies that every quasar should have a galaxy around it, but in several cases Bahcall found no clear evidence of one. "This," he said when he announced his observations, "is a giant leap backward in our understanding of quasars...
Astronomers have been pondering the riddle of the quasars for more than 30 years, wondering what prodigious energy source could possibly make these starlike objects visible from halfway across the universe. The leading theory: a quasar is gas falling into a gigantic black hole. As the gas is compressed, it heats up to millions of degrees, glowing brightly enough to outshine an entire galaxy; occasionally, jets of hot gas spray out, like juice squirting from a squeezed orange...
...Since quasars lie billions of light-years from earth, astrophysicists thought they might never prove the theory. But radio astronomers report in the current issue of Nature that they have discovered something similar to a quasar in the Milky Way galaxy, right in our own cosmic backyard. The object is much less powerful than a typical quasar, but it appears to work on the same principle. And being a mere 40,000 light-years away, it will be easier to study...
...nearly the speed of light. (Because of its angle, the jet gives the illusion of moving faster than light, a physical impossibility.) The jet presumably comes from gas falling from an orbiting companion star into a black hole that weighs as much as a handful of stars. Typical quasars, in contrast, emanate from something with the mass of a million stars or more. Unfortunately, galactic dust largely hides the mini-quasar, so there is a limit to how much astronomers will be able to learn from it. But since they have found one, they might find others. And that could...