It has even changed the way we understand the cosmos. “Before Hubble, people conjectured that galaxies evolved with time,” says C. Robert O’Dell, professor of astrophysics at Vanderbilt University in Nashville and, as project scientist at the Marshall Space Flight Center from 1972 to 1983, a major figure in the early development of the telescope. “Hubble has allowed one to actually see those changes.” Quasars, for instance, turn out to be a kind of smoking gun. Unimaginably powerful sources of radio emissions, brighter than entire galaxies, quasars were initially viewed as mysterious objects found billions of light-years from us but unknown in our own galactic neighborhood. Were they just oddities, loners in the cosmos? Hubble images showed, on the contrary, that quasars always occur at the cores of distant galaxies and derive their energy from material being sucked into black holes that lie even deeper within the galactic centers. Which is to say that galaxies billions of years ago were different from what they are now.
“The name of the game is nail things down,” says O’Dell. “And that’s what Hubble has really done.”
Hubble also confirmed that planets, like quasars, form as the result of normal, not fluky, processes. Stars condense from huge clouds of swirling interstellar gas. Hubble has shown that not all the swirling material is drawn into the star. Some of it winds up orbiting the newborn star. “That disk of material that’s left behind is the material from which planets can form,” O’Dell says. “Before Hubble, we had spectroscopic and photometric evidence. But when you actually see these disks going around these nascent stars, then it all becomes believable. In the case of our sun, if you look at the distribution of planets across the sky, you see they’re all in the same plane. That’s because they came from the same disk of material left behind as this cloud that was forming the sun was collapsing.”
In 1929, when Edwin P. Hubble announced his discovery of the expansion of the universe, its rate—known as the Hubble constant—could only be estimated. The telescope named for him has provided more accurate measurements of the constant, resulting in a more reliable estimate of the age of the universe-between 13 billion and 14 billion years.
Triumph tends to look inevitable in retrospect. It isn’t, of course, and the Hubble’s development from pipe dream to reality was an especially long and bumpy ride. The father of the space telescope, astrophysicist Lyman Spitzer, first proposed the idea in 1946, championed it in the halls of Congress in the 1970s, and lived to conduct research with it before his death in 1997. The advantages of a space-based observatory were clear from the start: The atmospheric turbulence that blurs terrestrial telescopes would be surmounted, and parts of the spectrum that are absorbed by the atmosphere would become visible. Beginning in the 1960s, the encouraging results of feasibility studies gave the idea momentum, although there were also a few prominent naysayers who expressed doubt that a space telescope could ever be stabilized well enough to produce decent results.
The 1970s played out like a tag-team match between Congress, NASA, and the astronomical community. Funds were granted, funds were cut off; astronomers lobbied, Congress reconsidered; NASA scaled down, President Carter approved. Then came the turf wars—both within NASA and between NASA and the Space Telescope Science Institute that astronomers had insisted be set up to manage the science.
Meanwhile, in 1976, a young Ph.D. named Edward J. Weiler landed his first job, as a researcher for Lyman Spitzer, who was chairman of the astronomy department at Princeton. As a child, Weiler had scrambled out of bed before dawn to watch Alan Shepard and John Glenn blast off. Equipped with a cardboard telescope that his father, a steelworker, bought him, Weiler decided, at age 13, that he “wanted to go to Northwestern, be an astronomer, and work for NASA.” He was already showing signs of decisiveness.
Spitzer put Weiler to work on Copernicus, an early NASA satellite observatory for which he was principal scientist. Before long, Weiler was director of operations for the observatory at NASA’s Goddard Space Flight Center. In 1978 Nancy Roman, the first chief scientist for what was then called the Space Telescope and NASA’s first chief of astronomy, offered Weiler a job. The 29-year-old found himself at a crossroads.
“I was working for Lyman, who was a great scientist, a great thinker, a visionary,” Weiler recalls. “I was publishing three to five papers a year. That’s pretty good. But I had to ask myself: ‘Am I ever going to be at the level of Lyman Spitzer?’ Probably not. So when I was offered the job at NASA, which was a lifelong dream anyway, I thought, ‘Maybe I’ll have more impact on the field by, instead of doing the research, enabling the research to be done by other people.’”