Early results from the infrared astronomical satellite

For 10 months the Infrared Astronomical Satellite (IRAS) provided astronomers with what might be termed their first view of the infrared sky on a clear, dark night. Without IRAS, atmospheric absorption and the thermal emission from both the atmosphere and Earthbound telescopes make the task of the infrared astronomer comparable to what an optical astronomer would face if required to work only on cloudy afternoons. IRAS observations are serving astronomers in the same manner as the photographic plates of the Palomar Observatory Sky Survey; just as the optical survey has been used by all astronomers for over three decades, as a source of quantitative information about the sky and as a "roadmap" for future observations, the results of IRAS will be studied for years to come. IRAS has demonstrated the power of infrared astronomy from space. Already, from a brief look at a miniscule fraction of the data available, we have learned much about the solar system, about nearby stars, about the Galaxy as a whole and about distant extragalactic systems. Comets are much dustier than previously thought. Solid particles, presumably the remnants of the star-formation process, orbit around Vega and other stars and may provide the raw material for planetary systems. Emission from cool interstellar material has been traced throughout the Galaxy all the way to the galactic poles. Both the clumpiness and breadth of the distribution of this material were previously unsuspected. The far-infrared sky away from the galactic plane has been found to be dominated by spiral galaxies, some of which emit more than 50 percent and as much as 98 percent of their energy in the infrared-an exciting and surprising revelation. The IRAS mission is clearly the pathfinder for future missions that, to a large extent, will be devoted to the discoveries revealed by IRAS.     

Stars, galaxies, cosmos: the past decade, the next decade

Our perception of the universe has been altered by recent discoveries in astronomy, discoveries of new objects and of new phenomena, coming from a wide range of observing techniques. By 1990 astronomers expect to know more about the distribution of mass in the universe, the physics of energetic sources, and the intricate interconnections of astrophysical processes on a variety of spatial and temporal scales.     

New Instruments Shed Light On Astronomy's Future

KONA, HAWAII-The snowy 14,000-foot summit of Mauna Kea, with its bevy of powerful telescopes including the just-completed Keck, provided an appropriate backdrop for a recent ocean-side gathering of astronomers and engineers to discuss "Astronomical Telescopes and Instrumentation for the 21st Century." Last month's meeting was organized by the Society of Photo-Optical Instrumentation Engineers, and included a status report on liquid mirror telescopes, discussion of a space observatory that may make optical and x-ray astronomers best friends, and a modest proposal to cover the globe with a network of small, automated telescopes.     

Dark matter, structure, and strings

In late July, about 150 astronomers gathered at the University of California, Santa Cruz, for a 2-week workshop on "Nearly Normal Galaxies." As the title suggests, the discussion was wide-ranging. Yet two issues stood out: dark matter and the large-scale structure. In itself this was hardly surprising, since these two issues have haunted extragalactic astronomy for nearly a decade. Indeed, they are central to an understanding of how galaxies formed. But some of the most dramatic findings have only been announced this year. Thus, the Santa Cruz workshop came at an especially opportune moment. In the following briefings, Research News draws on the workshop presentations to summarize astronomers' latest thinking on these subjects.     

Blood out of a stone

Almost 50 years ago, astronomers provided evidence for powerful radio emissions localized in two giant "lobes" on opposite sides of elliptical galaxies. These lobes are now known to be powered by jets emanating from black holes at the centers of the galaxies. In his Perspective, Blandford discusses how the black hole may generate the jets. He highlights the report by Koide et al., who have simulated one mechanism for supplying the jets with energy via a magnetic connection to the gas just outside the black hole's event horizon.     

PLANETARY SCIENCE: Saturn Wins Satellite Title With New Moons

This week an international team of astronomers announced the discovery of four new moons of Saturn, restoring the ringed planet to its status as commander of the largest retinue of satellites in the solar system. Their appearance should help researchers understand not just how the new moons were formed but also how the giant planets themselves came to be.     

ASTRONOMY: Researchers Get Spectrum Bands

Radio astronomers have been in danger of losing a precious band of the electromagnetic spectrum--the millimeter wavelengths, which promise insight into subjects as diverse as the origins of life and the birth of stars--to the burgeoning telecommunications industry, as millimeter wavelengths also look promising for transmitting high-bandwidth wireless information over relatively short distances. Earlier this month, however, astronomers won an international agreement that guarantees critical wavelengths safe for research.     

Quasars at 25

In the quarter century since the first optical identification of a "radio star" (3C 48), astronomers have come to general agreement that the underlying quasar energy source is accretion onto a massive black hole. There is much less agreement on the detailed physics of the processes by which this energy is converted to the forms observed, but this has not prevented the objects from serving as valuable probes of the universe at distant times and places.     

Pinwheels in the Quintuplet cluster

The five enigmatic cocoon stars, after which the Quintuplet cluster was christened, have puzzled astronomers since their discovery. Their extraordinary cool, featureless thermal spectra have been attributed to various stellar types from young to highly evolved, whereas their absolute luminosities place them among the supergiants. We present diffraction-limited images from the Keck 1 telescope that resolve this debate with the identification of rotating spiral plumes characteristic of colliding-wind binary "pinwheel" nebulae. Such elegant spiral structures, found around high-luminosity Wolf-Rayet stars, have recently been implicated in the behavior of supernovae light curves in the radio and optical.     

ASTROPHYSICS: Neutron Stars Imply Relativity's a Drag

A new finding, based on x-rays from distant neutron stars, could be the first clear evidence of a weird relativistic effect called frame dragging, in which a heavy chunk of spinning matter wrenches the space-time around it like an eggbeater. Using data from NASA's Rossi X-ray Timing Explorer, three astronomers in Amsterdam found circumstantial evidence for frame dragging in the flickering of three neutron stars in binary systems. They announced their results in the 1 September issue of The Astrophysical Journal.     

Dwarfs and dim galaxies mark limits of knowledge

When 250 astronomers met in Cardiff early this month at the U.K. National Astronomy Meeting, sponsored by the Royal Astronomical Society and the Particle Physics and Astronomy Research Council, they grappled with some big problems, among them the age of the universe and its mass. They also took on an even bigger metaproblem: How confident can they be in their knowledge about cosmic origins?     

Astronomers gossip about the (cosmic) neighborhood

The Hague, Netherlands, last month welcomed 2000 astronomers from around the world for the 22nd General Assembly of the International Astronomical Union (IAU). From 15 to 27 August, they participated in symposia and discussions on topics ranging from the down-to-Earth issue of light and radio-frequency pollution to the creation of elements at the farthest reaches of time and space, in the big bang. Some of the most striking news, however, came in new findings from our galaxy and its immediate surroundings.     

ASTRONOMY: The Virtual Observatory Moves Closer to Reality

Data from decades of observations by dozens of instruments may soon be accessible over the Internet, changing the way that astronomy is done around the world. The National Virtual Observatory will be an electronic web that gives astronomers access to terabytes of celestial data with the click of a mouse. The virtual observatory promises to make possible new analyses of the heavens by weaving together information from facilities around the world--and in space.     

U.K. science budget. Gene jocks, data crunchers hit jackpot

Unveiling its science spending plan for the next 3 years, the U.K. government last week announced major new investments in three key areas: tracking disease genes, leveraging the Internet for data analysis, and supporting emerging industries such as nanotechnology and bioengineering. Although these programs cut across a range of disciplines funded by the U.K.'s science councils, the government also bestowed a long-anticipated gift on astronomers: membership in the European Southern Observatory, which will give U.K. researchers access to the world's largest optical telescope.     

The strange periodic comet machholz

The recently discovered periodic comet Machholz 1986 VIII (1986e) travels closer to the sun than any known planet and any known comet with an orbital period of less than 150 years, thus providing astronomers with a unique object for studying cometary evolution. The comet is spiraling steadily closer to the sun, from perihelion distance q [unknown] 0.9 astronomical unit at about A.D. 700 to q [unknown] 0.13 at present (orbital period, 5.25 years), to an expected q [unknown] 0.03 by about 2450; should the comet survive such increasingly close perihelion passages, q will begin steadily to increase shortly thereafter. A review of observations made since discovery is presented, together with a discussion of numerical investigations of the comet's orbit over 4000 years and prospects for observing the upcoming return to perihelion in 1991.     

Electronic optical astronomy: philosophy and practice

The changes resulting from this electronic revolution have an impact as great as or greater than those from any of the major instrumental developments of the past. In previous times astronomers could only hope for the observational power that can now be realized by modern electronic instrumentation.     

PLANETARY SCIENCE: Newfound Worlds Hint at Hard-Knock Life

Last week at the International Astronomical Union 24th General Assembly, astronomers announced nine newly discovered planets orbiting other stars. The roster of extrasolar planets, now nearing 50, suggests that stars are fecund breeding grounds for worlds but that young planets must battle hordes of rivals for a handful of stable orbits.     

AMERICAN ASTRONOMICAL SOCIETY MEETING: Cool Comets, Barren Clusters, and a Maxed-Out Universe

About 900 astronomers gathered 2 weeks ago near the birthplace of Eastman Kodak Co. to share their latest pictures of the sky at the American Astronomical Society's 196th Meeting. Notable findings pointed to a cold origin for comet Hale-Bopp, a nasty environment for extrasolar planets, and a maximum size for the biggest structures in the universe.     

Quasars and a dwarf star break the rules in tucson

Earlier this month, more than 2000 astronomers convened in Tucson, Arizona, for the American Astronomical Society's largest meeting ever. Even the war drums beaten by a few local Apaches and their supporters, protesting a University of Arizona telescope project, could not drown out lecture-hall and corridor discussions of topics such as naked quasars, flaring stars, and planetary searches.     

ASTRONOMY: Brown Dwarf's Flare Opens X-ray Eyes

When the Chandra X-ray Observatory pointed its snout at a failed star 16 light-years away, astronomers expected it to see little sign of activity. Instead, the orbiting telescope got smacked in the eye by an x-ray flare--and astrophysicists are still trying to explain why.