Infrared probe 'calls forth mysteries from universe'
IRAS - the heat-observing infrared Astronomy Satellite - has returned its first big scientific dividend. Since it was launched on Jan. 25, it has opened a vision of the universe never seen before. With it, project scientists have observed stars at the very early moments of their life, peered through interstellar dust that blinds ordinary telescopes to see the very center of our galaxy, and then looked beyond that to gain a new view of objects at the edge of the universe.Skip to next paragraph
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IRAS project scientists are still working intensely to gather as much data as they can before their space-based instrument stops functioning next January. But they took time out Nov. 9 to present some of their initial findings. Gerry Neugebauer, leader of the United States IRAS scientific team, summarized them:
* A band of dust circles the sun between the orbits of Mars and Jupiter. It may be the debris of asteroid collisions.
* Comets that are faint and hard to see with ordinary telescopes are more numerous than suspected. IRAS has already discovered five of them. Also, many comets have much more dust accompanying them than previously thought.
* Researchers may have found the origin of the Geminid meteor stream, which appears every December. IRAS has turned up a tiny object, about 1.2 miles in diameter, moving along the Geminid path. It may be the remains of a comet that spawned the meteors. It's called minor planet 1983TB, and its orbit passes within 9 million miles of the sun, closer than the orbit of any other known body.
* The formation of star systems like our solar system may be much more common than has been thought.
* Betelgeuse - the giant red star in the constellation Orion - has expelled massive amounts of matter that are grouped to one side of the star. It may be lagging behind as the star moves through interstellar dust. This would be the first observation of such motion.
* At some infrared wavelengths, the sky is dominated by galaxies that are not prominent in visible light.
* Large-scale infrared views of the sky show ubiquitous, wispy dust clouds. Project scientists call them ''infrared cirrus,'' drawing an analogy to the wispy cirrus clouds high in Earth's atmosphere. Some of this dust may be located nearby as a kind of outer veil of our solar system.
Scientists presenting these findings at a press conference at the National Aeronautics and Space Administration (NASA) headquarters here conveyed a sense of excitement, a sense of being part of what is an epochal project. They have opened a new window on the universe.
This kind of major advance first happened when optical telescopes were invented. It happened again a little over three decades ago, when astronomers began to study the cosmos with radio waves. Within the past 15 years and with the help of satellites to carry instruments beyond the atmosphere, astronomers have begun observing with X-rays and at ultraviolet wavelengths. Each of these new views has revealed phenomena that scientists had scarcely dreamed could exist - such as quasars, compact objects that have more power than a galaxy of ordinary stars.
Now, with the first infrared telescope in orbit, yet another vision of the cosmos is being revealed. Infrared (heat) radiation is the best way to observe material that is cold, such as the dust and gas from which stars form. It can also enable astronomers to ''see'' through dust clouds such as the dark masses that obscure our view of the center of our own galaxy.
Nancy Boggess, an IRAS program scientist, called it ''a tremendously exhilarating experiencee.'' Yet, she explained, it is only a small beginning. IRAS scientists have scarcely glimpsed the wonders their data contain.
''Many of the best discoveries may still be in the can,'' Dr. Boggess said, referring to the vast amounts of data that have been stored. It will take years of work by project scientists and other astronomers to mine the wealth of information that is pouring in at the rate of 350 million data bits a day. Trying to sift through even a part of this now is doing ''science on the run,'' she said.
Yet even when all the studies have been made, the findings are only likely to raise new questions. IRAS is a survey instrument. It is mapping out the infrared sky. An even more powerful instrument is needed for follow-up studies. This is likely to be the shuttle infrared telescope facility, to be available in the 1990s.
IRAS - a joint British, Dutch, and US project - is a powerful instrument. Its telescope can ''see'' the infrared radiation from a speck of dust two miles away. Yet this isn't good enough to pick up the dust and planets in our solar system if IRAS were observing it from the nearest star. The shuttle facility will be able to study many star systems and detect any accompanying dust or planets. It will be the advance needed to build on the foundation that the IRAS project is now laying.
Meanwhile, IRAS scientists are caught up in the adventure of seeing the infrared cosmos clearly for the first time. NASA administrator James Beggs captured their mood when he said, ''We called forth mysteries from the universe and they came.''