The latest photographs were taken by the Hubble's new Advanced Camera for Surveys, which began operating a month ago. Looking at them is like looking at a fundamental principle of physics. You see both energy and matter, revealed with a vibrancy that is simply overpowering. As forms, as colors, these objects are entrancing. But it's only when you begin to realize what these forms are that the real wonder appears. Beyond the uniformity of the naked-eye universe, there is this other universe, the one Hubble discovers with astonishing clarity. This is a place full of discordant objects, of cataclysmic disturbances. Galaxies devour each other. Stars form in infernos of gas and dust and light. And they do so against the backdrop of a sky that is almost unimaginably deep.
For what the Hubble cameras show us, especially in their new incarnation, is time itself. The distance of the distant objects in these images is measured as much by their relative youth, by how far back in time we must peer to see them, as by their distance measured in a spatial dimension. By now it sounds almost natural to say that among the objects revealed in these new images are galaxies that were formed when the universe was only a billion years old. It sounds natural until you really think about it, and then, swiftly, the scale of the Hubble revolution becomes apparent. It has taught us to see the properties of a universe humans have been able, for most of their history, to probe only with their thoughts.
August 2, 2003
After some early technical modifications to repair flaws in its primary mirror, Hubble has been a resounding success. Floating well above the distorting effects of the atmosphere, the observatory has been able to detect extremely faint objects that cannot be found by earthbound telescopes. Hubble has provided the clearest and deepest views of the distant universe, calibrated the age and expansion rate of the universe, and detected supermassive black holes that seem to lie at the core of most galaxies, among myriad other achievements.
The Hubble telescope is supposed to be serviced by a shuttle mission in the next year or two, then brought down from orbit in a controlled descent in 2010. The funds saved by phasing it out will be pumped into a follow-on instrument: the James Webb Space Telescope, scheduled to be launched in 2011. That telescope will be placed in an extremely high orbit and will be designed to operate at infrared wavelengths, which are crucial to observing very early cosmic history and the formation of stars and planets. Hubble mostly detects visible light.
Unfortunately, the loss of the shuttle Columbia has cast doubt on whether the next scheduled servicing mission to Hubble can proceed without undue risk to the astronauts. Meanwhile, NASA is assessing whether an additional servicing mission should be mounted later in the decade to keep the telescope operating past 2010.
The problem, as always, is money. Congress has ordered that whatever is done with Hubble cannot siphon money away from the James Webb Space Telescope. That is a reasonable stance, but the Webb telescope may well fall behind schedule and could even suffer a disabling failure far beyond the reach of astronauts to repair. Thus it would make sense to keep Hubble going, at least until the Webb telescope is successfully in orbit. If money needs to be diverted from somewhere, we suggest that it be taken from the partly completed space station circling aimlessly overhead. No experiments planned for the space station come remotely close in importance to Hubble's potential for discoveries. Curtailing the Hubble telescope before a successor has been launched seems foolish.
By all accounts the Hubble Space Telescope is one of the most productive scientific instruments in history. Orbiting high above the distorting effects of Earth's atmosphere, it has peered far out into space and back toward the beginnings of time, producing images of startling clarity. It has detected extremely faint objects that can't be seen from the Earth, calibrated the age and expansion rate of the universe, detected supermassive black holes in the cores of galaxies and generally helped revolutionize our understanding of the universe. A distinguished panel of astronomers judged that Hubble "has arguably had a greater impact on astronomy than any instrument since the original astronomical telescope of Galileo."
Yet now, just as Hubble was scheduled for a major rejuvenation, the National Aeronautics and Space Administration has consigned it to slow death. The agency has canceled a planned servicing mission that would have upgraded Hubble's instruments and extended its life past the end of the decade, making it likely that the telescope will run out of battery power and functioning gyroscopes by about 2007. Congress needs to prevent the premature loss of this valuable instrument.
Cancellation of the servicing mission is being justified on safety grounds, but that is not the whole story. Indeed, it looks as if Hubble is being sacrificed primarily to make way for President Bush's grand new plans to send astronauts to the Moon and Mars in future years. Once the shuttles are deemed safe enough to resume flying, probably early next year, a shuttle flight to Hubble will be no more risky - and possibly even less risky - than flights to the space station. The real safety issue comes up if something goes wrong. A shuttle near the station might find safe haven and help in repairs. A shuttle near Hubble could not.
Our guess is that with NASA on high alert after the Columbia tragedy, the next shuttle flights will be the safest ever. Astronauts are paid to take risks, and there would be no shortage of volunteers for a Hubble mission that seems no more risky than other flights and a lot more important scientifically.
The Bush administration argues that Hubble has passed its prime, that its uniqueness is diminishing, that advances in ground-based telescopes enable them to do some of Hubble's work and that future breakthroughs will require telescopes able to search in other wavelengths than those used by Hubble. There is a germ of truth in all those contentions, but a parade of experts have argued that Hubble, if serviced and updated, has years of great work ahead. There seems little doubt that the science still to be done on Hubble is far more important than anything likely to be accomplished on the space station.
The chief reason for Hubble's demise is almost certainly NASA's need to use its shuttles to finish building the space station by 2010 so that the shuttles can be retired and the money used for the president's Moon-Mars exploration initiative. The agency will be lucky to complete the station on time even with all three remaining shuttles devoted to the task. Servicing the Hubble would be a diversion.
The administration essentially argues that the scientific returns from extending Hubble's life are not worth the risk and effort of a servicing flight. Our feeling is just the opposite. The gains from extending Hubble's life are real and achievable and should not be sacrificed for a distant exploration program that for now is mostly wishful thinking and can surely be delayed a bit.