For centuries astronomers were limited by the biology of the human eye. Though electromagnetic radiation comes in all sorts of wavelengths, from great swelling radio waves kilometers long to gamma rays shorter that the radius of the tiniest nuclear particles, astronomers from Galileo to Hubble were cooped up in the tiny range of wavelengths to which the human eye is sensitive, with only the odd day trip into the nearby bits of the infrared to alleviate the crowding. After the Second World War a few astronomers built the first generation of radio telescopes, but the rest of the village stayed firmly in the red-to-blue world of its forefathers until the ’60s. Then everything went a bit wild. Satellites opened up mind-blowing new realms of astronomy: the extreme ultraviolet and the deep infrared, gamma rays and X-rays. A new generation ran amok all over the spectrum, discovering amazing things about the universe. If you stared into the microwaves hard enough you could actually see the afterimage of the big bang. Far out.
Since the 1960s astronomers have been trying to come to terms with all these new ways of seeing the universe. Now they have more or less made it: “There simply aren’t any neglected fields anymore,” says Virginia Trimble of the University of Maryland, a member of the IAU’s executive committee. Whatever the wavelength, whatever the object, someone is making observations. But the opening of the new wavelengths is only part of the reason for the astronomy boom. As computing power has grown, so has the number of ways of applying it to astronomy. New manufacturing and data-processing technologies are allowing earthbound telescopes to get bigger and do more than ever before. Light from separate telescopes can be combined to produce exquisite detail. Thin mirrors can be bent to compensate for atmospheric distortions, sharpening images. And inordinately large mirrors can now be designed to be made in segments.
For a long time the largest telescope in the world was the peerless 200-inch (five-meter) reflector at Mount Palomar, California. Now the world has a dozen or more telescopes in the eight- to 10-meter range. There are plans in America to build a giant segmented-mirror telescope that will have a mirror nine times larger still. The European Southern Observatory, which is putting the finishing touches to its prosaically named Very Large Telescope, a composite system with four eight-meter mirrors, has grandiose plans for a later instrument with a mirror 100 meters across. This wonderfully named Overwhelmingly Large Telescope would compare with the Great Pyramid in size, and its ability to gather light would far exceed the sum capabilities of all previous telescopes ever made. Optical astronomers are not the only ones thinking big. Radio astronomers at the Manchester meeting formally inaugurated a committee looking into the possibility of building a Square Kilometer Array, a set of radio telescopes that would improve on today’s best a hundredfold. A precursor project, the One Hectare Telescope, is already in development under the auspices of the SETI Institute, an organization devoted to the search for signals from alien species.
The first such search was made 40 years ago by Frank Drake, who now works at SETI (which stands for Search for Extraterrestrial Intelligence). The searches being made today are 100 trillion times more powerful than Drake’s first attempt. A lot of that improvement has come from increased computing power; Moore’s law states that computing power doubles every 18 months, but improvements in other technologies have served to amplify that already impressive acceleration, so that SETI’s searching power doubles every nine months or so. Computers get a hundred times better in a decade; SETI’s radio telescopes get 10,000 times better. In a few decades, according to Drake, it will be possible for radio astronomers using the next technology on from the Square Kilometer Array to listen to the whole sky at all frequencies all the time. Well before that, optical astronomers hope to have a telescope that maps the sky with exquisite sensitivity every week, producing more than a trillion bits of data a day.
This all costs a fair amount of money, much of it from the public purse (though telescopes have always attracted private money, too: the SETI hectare array is funded by Microsoft cofounder Paul Allen). In return it provides some new technologies–the techniques it develops can be very practical–but that’s not really the point. Astronomy is a scientific field going through a whole set of golden ages at once. And it’s also an inspiration. There’s something pleasingly pure about the way the stargazers push the possibilities of their profession just as aggressively and creatively as the computer researchers and biotechnologists do, with no need for any reward but their magnificently expanding visions of our magnificently expanding universe.
