Astronomers Expect The Unexpected At First U.S. Conclave In 27 Years

Astronomers are used to surprises, so they ought to be more than comfortable at the 20th General As- sembly of the International Astronomical Union in Baltimore next month: First, there is no pre-published program listing titles of talks to be given. Second, the main topic of conversation won’t be what anyone expected when the conference was planned. The intent had been to analyze —and celebrate—the latest findings from the Hubble Space Telescope. By midsummer 1988, the Hubble would surely have been launched aboard a U.S. shuttle, conference organizers reasoned, so what better time to hold the first General Assembly in the United States for 27 years? In fact, the U.S. National Committee for the IAU endorsed Johns Hopkins to host the event, assuming that right on campus at the Space Telescope Science Institute, data from the Hubble would be divulging incredible celestial secrets from the dimmest reaches of the universe. Instead came the tragedy of the Challenger, which has put off the launching of the Hubble until 1989 at the earliest.. But to the conference’s rescue—and to the delight of astronomers everywhere—came Supernova 1987k And its effects on the meeting will be apparent. Countless papers on the supernova are expected to be presented, and a daylong session on the event, sponsored by astronomers from a number of different disciplines, will be a highlight of the conference, according to Arthur Davidsen, director of the Center for Astrophysical Sciences at Johns Hopkins and co-chair of the General Assembly’s local organizing committee. Astronomers predict that the conference will be rife with speculation—perhaps even spirited debate—over the former star’s soon-to-be-revealed new identity. Within the next two years—perhaps even this summer—the debris that was the interior of the star will clear and allow scientists to peer into the very heart of the supernova. “Everybody thinks a neutron star was born, but no one has seen it yet,” notes Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics. And while circumstantial evidence strongly suggests this is a neutron star, the possibility still remains that the core of the star collapsed into a gravitational field so severe that not even light can escape: a black hole. If so, this would be the first black hole, ever proven to exist. Such a find would be “the greatest discovery of 20th-century science," says astrophysicist Kenneth Brecher of Boston University. The fortuitous appearance of the supernova hasn’t obliterated all conversation about the space telescope, though. One question-and-answer forum will serve an important function for the scientists who intend to meet the October 1 deadline for proposing projects for the orbiting observatory. The delay in launching the Hubble has had a positive aspect: The efficiency of the five major instruments on board—two cameras, two spectrographs, and a polarimeter—has been improved, and astronomers will receive an update on the new parameters of the instruments at the Baltimore meeting. These im provements mean that scientists may be able to get more bang for their buck—or even propose experiments not previously thought practical. In addition to the supernova and telescope, the expected 2,000 attending astronomers—one-quarter of the global population—will be offered three invited talks, including one marking the 25th anniversary of the discovery of quasars. This discourse will be given by Caltech’s Maarten Schmidt, one of the first to take note of quasi-stellar objects. In the score of years since their detection, knowledge of quasars has not grown appreciably, notes Schmidt, and, in fact, some astronomers remain skeptical that the red shift associated with the phenomena indicates that they are a very large distance away. That distance—the closest quasar is one billion light years from Earth— puts a stumbling block in front of investigators. “We have to just sit here and understand from a few photos,” says Schmidt. He adds that astronomy is a “passive science,” and that astronomers, unlike some of their other colleagues in science, cannot go into a laboratory and “pour acid on things.” As for the rest of the sessions, their contents will be as mysterious as a supernova center before the dust settles. In a break from the usual organization of a major scientific meeting, there is no formal program listing the 1,000 papers expected to be presented. “Traditionally the General Assembly is a chance for everyone to get together to hear their colleagues, not to be so concerned about what is happening and when and where,” says Davidsen. This organized confusion is also the result of a lack of a central authority indeed, the meeting is driven by 42 international commissions of scientists who have organized around specific areas of interest. (Commission #40, for example, is devoted to radio astronomy.) While the commissions may sponsor their own symposia at any time, the triennial General Assembly is their only scheduled opportunity to gather their members together. During the course of the assembly, ‘each commission will meet at least several times. And while astronomers will have received an agenda listing the papers to be presented by the members of the two or three commissions they may belong to, anyone wishing to peruse the topics of another commission must wait to examine that group’s bulletin board in Baltimore. Because of this method of operation, the choicest aspects of the 20th General Assembly, perhaps, cannot be anticipated. Observes Davidsen: “We don’t know what it will be until it is upon us.” From one who is willing to wait decades for the secets of the universe to reveal themselves, this is certainly a form of praise.

Astronomers Expect The Unexpected At First U.S. Conclave In 27 Years

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