The Value of Hubble
Hubble Vision: Astronomy with the Hubble Telescope
The “first light” image from the Hubble telescope was almost universally hailed as the beginning of a new era in astronomy and cosmology. Upon closer scrutiny, however, a team of experts discovered that the photograph-which showed a star cluster over 1,300 light years distant-was poorly focused, a smudged halo of light rather than the tight image they had expected. The result was a first-order public relations disaster: once the darling of science journalists, the Hubble telescope came to embody everything wrong with the federal government’s “big science” projects. Critics charged that not only were these massively expensive ventures available mainly to narrow scientific communities but they were a bad investment: the technology was so complex that failures, sometimes catastrophic, were statistically inevita-ble. The general feeling was that perhaps it was time to return to projects designed for small laboratory settings.
But in Hubble Vision, science journalist Carolyn C. Peterson and astronomer John C. Brandt affirm that investment in the Hubble telescope was indeed justified. Granted, the telescope is a dauntingly intricate machine. The authors admit that virtually every major system is operating under some flaw that limits its performance, or, in a few cases, renders multi-million-dollar devices inoperable. The star-cluster image that occasioned such praise and, later, such approbation came by its imperfections through normal wear: a tiny speck of paint that chipped off the cap of a testing device caused a light leak-and hence a crucial mirror was ground with an error of about a micron, or one-millionth of a meter. A flapping solar panel that jiggled the telescope smeared still other images. Moreover, software problems continue to surface, such as the ones that have affected the “fine guidance sensors,” which have sometimes focused the telescope on the wrong target. Yet because of the unique capabilities of the telescope’s many instruments, the authors point out, we are witnessing advances in virtually every aspect of astronomy, astrophysics, and cosmology.
Since the Hubble operates in space, where the filtering effects of earth’s atmosphere are not a problem, its “Goddard high-resolution spectrograph,” or GHRS, can zero in on ultraviolet radiation emissions in unprecedented detail. And through spectroscopy-a technique that breaks down those emissions into their component wavelengths-research-ers can begin to understand the life cycles of heavenly bodies. The reason is that different wavelengths are associated with specific chemical elements, which we know to behave in predictable ways. Beta Pictoris, a star surrounded by elements that appear to be coalescing into planets, is one of hundreds of subjects being studied. Observations of the various elements falling into its core, as well as those forming orbits around it, have enabled astrophysicists to record the stages of a star system’s development for the first time. GHRS can even determine the chemical composition of precise regions within Beta Pictoris.
The telescope could also challenge a pivotal notion of its namesake, Edwin Hubble, as astronomers attempt to more accurately define the “Hubble constant”-that is, the rate at which galaxies are receding from one another. Because of its vantage point in space, where, again, there is no atmosphere to complicate matters, the Hubble telescope can greatly refine techniques for measuring galactic distances, and if the refinements turn out to be significant, it would mean that galaxies are receding from one another faster or more slowly than Hubble had thought. And that, in turn, could mean a change in our notion of the age of the universe: a faster rate suggests a younger universe, a slower rate an older one.
Perhaps the most striking discoveries are those that do not quite fit into known science. Peterson and Brandt explore a long roster of such phenomena, including the “chemically peculiar” star Chi Lupi, which exhibits extraordinary concentrations-100,000 times higher than normal-of mercury, gold, and platinum. Some scientists believe that small differences in the radiation coming from the core of the star may create pressures that concentrate these unusual elements on the star’s surface. Another hypothesis has to do with the observation that Chi Lupi is part of a “binary system,” or two stars that revolve around each other: theoretically, Chi Lupi’s gravitational interactions with its binary companion could have exerted the kinds of forces that would bring the elements in question to the fore.
Or take Supernova 1987a, which, as the Hubble telescope has shown, developed a series of mysterious outer rings years after the explosion responsible for it spread into space. No one knows why, and if this development cannot eventually be explained, it could indicate that the conventional theories through which explanations are being sought are simply inadequate. The outcome could be fundamental revisions in our view of the universe.
Astronomy and Social Values
This is exciting stuff, and it makes for a very convincing case in favor of the Hubble telescope. But the authors’ argument would have been stronger if they had not relied so heavily on their write-up of the telescope’s findings. For one thing, they would have done well to devote more attention to the quality of the photographic illustrations in the book. While they do provide a few arresting images, such as a shot of the mysterious rings emanating from Supernova 1987a, many of the best photos are credited to Voyager or ground-based telescopes.
Also, any broad cross-sectional view of research conducted in a time of explosive advance is bound to leave some things out, and as it happens, Hubble Vision leaves out one of the telescope’s most interesting contributions: evidence that the number of galaxies in the universe could be 10 times greater than we had previously thought. Scrutinizing Hubble’s clearer pictures of what, from the ground, appears to be empty space, astronomers can actually discern additional galaxies that are both far away and in the early stages of formation.
More significantly, the book fails to give due consideration to features that indicate the telescope’s larger social value. For instance, Hubble offers an unusual avenue for public participation. Potential observers, whether professionals or not, can apply for time allotments on it through an open peer-review process. Jim Secosky, a high school biology teacher preoccupied with the unexplained brightening of Jupiter’s moon Io, was allowed to use the telescope to investigate a hypothesis that evaporation of sulphur dioxide frost was the cause. In making such opportunities available, the Hubble telescope is increasing the participation of both students and amateurs in real-life science.
But even though its case for the telescope could be stronger, Hubble Vision will bring a sense of wonder to a wide audience of science enthusiasts. Not only do the authors offer a rich menu of cutting-edge discoveries but they explain scientific issues behind the findings so that lay people can understand them. And in performing this basic service, the book could, finally, help make the debate over big science more meaningful. The kinds of advances Hubble has facilitated result from a research agenda that is well defined yet continually expanding as more information rolls in. The fact is, however, that not all big science projects have such a flexible agenda. A prime example is the superconducting supercollider, whose mission was rigidly circumscribed to “smashing atoms” in search of exotic particles. Reflecting on such matters, the reader soon begins to wonder if we might find a way to establish a clearer criterion of success for big science projects-and once that happens, a bit of subtlety has been restored to the subject. People are, at the very least, no longer thinking strictly in terms of dollars and cents.