Read First Light: The Search for the Edge of the Universe for Free Online Page A

sky—quasars—and who could help him get them—Jim Gunn. Maarten leaned back and put one ankle across the other knee; he was six feet, four inches tall and did not fit well under desks. He said, “This run is radically new. We have been looking for quasars at exceedingly high redshifts. Tonight is the first time we have ever tried to do this with 4-shooter. It is the most difficult thing we have tried so far—”
    “If you do that, Jim”—Barbara Zimmerman’s voice rose above the others—“it clears the register.”
    “Should I go for it?” Gunn asked.
    “I don’t know,” she said. “Hell, yes.”
    A clatter of computer keys, and then, “Oh, Lord, now what?”
    After a slight pause, Maarten Schmidt continued. “The statistical material on these high-redshift quasars is small. We don’t know much about their properties. We barely, if at all, understand quasars. Their fate, while they live, is purely speculative.” He stood up and squared his stack of papers. He crossed and recrossed the small room while he talked. He said that quasars whose light was shifted strongly toward the red end of the color spectrum were the most distant objects that an optical telescope could resolve—some of them lived, so to speak, at the edge of the universe. Quasars were not easy to find. In all of his team’s previous searches for deeply redshifted quasars, they had not found any of this class of object at all. “This is puzzling,” he said. “We know they are out there. So why aren’t we finding any? No, I am not worried, it is probably a matter of statistics. Perhaps there are not so many of these high-redshift quasars as we had originally supposed. Butwhen you don’t find a thing and you know it is there, then there is always the worry that you are doing something wrong.”
    Quasars are the most luminous objects in the universe. Although they shine at great distances from the earth—far, far beyond the Milky Way—they are so intrinsically brilliant that they appear in a telescope as points of light, like stars. They are not stars. Quasars are tiny objects, however. The core of a quasar may be no larger than a solar system. The energy that causes a quasar to shine is mysterious. Quasars do not “burn” in either a chemical or a nuclear sense of the word. Whatever energy powers a quasar, it is not the thermonuclear fusion that makes the sun shine.
    Most astronomers believe that quasars are a long distance away from the Local Supercluster—a long way from our neck of the woods. According to Hubble’s law, which is named after its discoverer, Edwin Hubble, the galaxies are moving away from one another. The universe, as an object, is in a state of expansion. Since the totality of human civilization occupies a stroboscopic instant in the unraveling of cosmic time, objects in the sky appear to be motionless, as if caught in a strobe flash, when, in fact, a dance is happening out there. Some galaxies are spinning on their axes, and some galaxies are circling around each other. Two galaxies can touch for a while in a pas de deux, or one galaxy can burst through another, tearing both apart. At the same time, in general, galaxies are slowly withdrawing from one another, because the universe is expanding. Astronomers can discern such movement only through measurement. Spectroscopy—the division of light into its component wavelengths—reveals not only that spiral galaxies are spinning, but also that our galaxy is receding from virtually all other galaxies; that all galaxies are receding from one another (except those bound into clusters by mutual gravity). The galaxies are scattering, somewhat like a crowd leaving a stadium. This general expansion of the universe is called the Hubble flow. The galaxies are being carried along in the Hubble flow. As a result, the light of most galaxies—as seen from earth—is stretched downward in frequency toward the lower end of the color spectrum, toward red. This is a phenomenon