Oodles of 'noodles' found in galaxy.

Oodles of "noodles' found in galaxy

Most people--including most astronomers--would consider stars to be the most common components of a galaxy. Now, a group of astronomers has found strange new objects, called "compact structures in the interstellar medium,' that, by statistics at least, should prove to be more numerous than stars.

"Compact' means that these objectsare about as big as the earth's orbit around the sun, and therefore larger than all but the biggest stars. They are, however, much smaller than the clouds that previous observations have detected in interstellar space. They reveal their presence by diffracting the radio waves coming from distant quasars. Ralph L. Fiedler, Brian K. Dennison and K.J. Johnston of the Naval Research Laboratory in Washington, D.C., and Anthony Hewish of Mullard Radio Astronomy Observatory in Cambridge, England, report the discovery in the April 16 NATURE.

The finding came from a program ofdaily observations of 36 quasars over a period of seven years. The data show that certain quasars undergo what seem to be sharp occultations: Their radio intensity drops off sharply, remains down for a month or so, then rises sharply again. It's as if a blob of ionized matter moved between the observer and the quasar. The objects move too fast to be near the quasar--to be that far away, they would have to go at 500 times the speed of light--so the observers conclude they are in our galaxy. Previous observers didn't see them, Fiedler says, because they didn't observe the same quasar at close enough intervals.

If the objects are roughly spherical,each one contains about the mass of an asteroid. But they could be elongated shapes, "more like noodles,' Fiedler says. How they form, how long they last and what they may become are all open questions. If they last any length of time, something must supply the energy to maintain them in an ionized state. That too is a mystery. From the five instances so far found, the observers estimate that these objects may prove to be 500 or 1,000 times as numerous as stars.

Other astronomers are "very excited'by the discovery, Fiedler says, and are going to look at their favorite quasars for the same effect. His group plans to extend their observations to 400 quasars. If they find some good candidates, he says, they can then get some very long baseline interferometry done, to elucidate fine details of the structure of these objects.