The big bang, black holes, dark matter, dark energy, extrasolar planets, brown dwarfs, quasars, pulsars, cosmic rays, the space-time continuum, galaxies and more galaxies. Do you see what Galileo started?
It's been 400 years since University of Padua professor Galileo Galilei, a precocious Italian of relatively modest achievement, had the bright idea of turning a modified spyglass toward the night sky. What he saw forever shattered the ancient Earth-centered cosmos.
Four centuries later, telescopes are among the greatest marvels of civilization, and they reveal daily that the universe is vaster, stranger and more violent than Galileo could have imagined. He incited what has become a compulsion to tunnel deeper into the sky, and the universe shows no sign of running out of surprises.
This is going to be a particularly big year for telescopes, and not just because it's officially the International Year of Astronomy, featuring astronomy conferences, space-related art projects, and telescopes flooding the market at $10 and up. There will also be breaking news.
In March, the United States will launch a new orbiting telescope, Kepler, with the goal of discerning Earth-like planets hidden in the starlight of distant suns. Then, in May, astronauts aboard the space shuttle will make a final trip to the nearly 20-year-old Hubble Space Telescope, inserting a new camera and other instruments to squeeze a little more magic out of the first of the space-based observatories.
But even if it's a Golden Age of Astronomy, it's also one of feverish competition, a scramble for dollars in a time when governments have bigger worries than black holes at the centers of galaxies.
Surplus of ideas, shortage of funds
NASA is astronomy's biggest supporter, funneling nearly $1.2 billion into astrophysics in its '09 budget. The National Science Foundation, the Energy Department, the military and nonprofit groups deliver hundreds of millions more. Even so, astronomers have a surplus of great ideas for telescopes and a shortage of funds. "As it is, we're waiting a decade and a half before we get even one of our highest-priority telescopes up and running," said Kevin Marvel, executive officer of the American Astronomical Society, which held its annual meeting here last week.
The astronomical community is launching a once-a-decade survey to recommend the next generation of instruments. Land-based telescopes will compete against space-based instruments. Infrared telescopes will throw elbows at radio telescopes. X-ray and gamma-ray telescopes will jockey for their slice of the pie.
Everything will be supersized. The biggest visible-light telescopes today have mirrors about 10 meters (32.8 feet) in diameter, but American astronomers want to build a telescope with a collecting mirror nearly 100 feet across: the Thirty Meter Telescope. Europeans hope to raise the bet with a 42-meter monster they call (in the slightly boastful parlance of astronomy) the European Extremely Large Telescope.
Radio telescopes on the drawing board are grander still, including one, the Square Kilometer Array, that would link a series of small dishes to create a collecting area of 1 million square meters.
Scheduled for launch in 2013 is NASA's James Webb Space Telescope, the designated successor to the Hubble. The JWST is capable of collecting some of the oldest, faintest light in the cosmos, emanated before the birth of galaxies, when the universe became transparent and light became free to move around — which is almost all the way back to the beginning of time itself.
What would Galileo think of that?
"He would be knocked speechless," said Owen Gingerich, eminent astronomer and sometime historian, wandering the astronomy meeting last week with a facsimile of Galileo's first astronomical treatise.
"He would be in shock," Marvel said, "and he would want telescope time — now."
Galileo's first instrument magnified objects about eight times their original size, Gingerich said. Galileo first looked at the moon. The ancient philosophers had seen the moon, sun, planets and stars as immaculate objects that circled the corrupt, filthy Earth, which was like the Dumpster of creation. But Galileo saw that the moon, far from being a perfect, crystalline sphere, had surface features. It had mountains and craters. It was a world.
With improved telescopes Galileo saw the phases of Venus, sunspots and then, most dramatically, four moons orbiting Jupiter. When he aimed his instrument at the Milky Way, he saw that it was full of "many, many stars" (the latest count is about 100 billion).
Galileo didn't invent the telescope — history gives credit to the Dutchman Hans Lipperhey, among others — and he may not even have been the first person to look at the night sky with one. An Englishman, Thomas Harriott, looked at the moon in the summer of 1609 and made some drawings of what he saw. But Galileo published his findings. Most important, he grasped the powerful philosophical implications of what he saw.
Galileo's observations validated the theory of Nicolaus Copernicus, who had died in 1543. The Copernican model featured the bewildering notion that Earth, which is seemingly stationary, is in fact spinning. And it declared that Earth isn't the center of the universe. The Vatican prohibited Galileo from teaching the Copernican model, but he hammered away, and ultimately faced charges of heresy.
Though spared a death sentence, he was forced to renounce his teachings and spent the remainder of his life under house arrest.
Galileo had the ultimate ally in the universe itself, which revealed new wonders with each incremental improvement of the telescope.
The night sky is essentially a database, crammed with information in the form of electromagnetic radiation, known more generically as light. You can't obtain all that information with a single telescope because light exists at different wavelengths. Our eyes are of a size adapted to capturing what is, by definition, the visible part of the spectrum, but if we had giant heads with eyeballs hundreds of feet in diameter, we'd see radio waves.
Astronomers seeking to solve a cosmic mystery have to decide which kind of eyes they need. For example, to probe the mysteries of the center of the galaxy — home to a black hole with the mass of a million suns — they use infrared telescopes, because the infrared light can pass through the dust clouds that obscure the galactic center.
One of the big questions that the Webb telescope will address is the chicken-and-egg problem regarding black holes at the center of galaxies. It's unclear what came first. A report last week, based on observations of extremely distant galaxies formed early in the history of the universe, suggested that black holes came first, acting like galactic seeds.
An even more basic question is: How big is the universe? Theorists grapple with the possibility that the mind-boggling cosmos we see is but a tiny bubble in a much larger (beyond mind-boggling, into mind-blowing territory) multiverse.
Galileo "wouldn't have had the cultural reference frame to appreciate or understand all this stuff," opines Andrea Prestwich, an astronomer with the Harvard-Smithsonian Center for Astrophysics. "First of all, he'd get stuck on the scale of the universe."
While cosmologists hash out the biggest questions, astronomers are taking on something slightly simpler and closer to home: How big is our Milky Way galaxy?
Astronomer Mark J. Reid, also with the Center for Astrophysics, tried to answer that question by using 10 telescopes spread across the continental United States, Hawaii and the Caribbean. The Very Long Baseline Array, as it is known, functions in certain respects like a single instrument with nearly the diameter of Earth.
Recently, the operators of the VLBA learned how to take into account such subtle, data-skewing effects as continental drift. The array is now so powerful, Reid said, that it would be able to read his PowerPoint slides from the moon.
By studying individual stars and calculating their speed and distance, Reid discovered that the Milky Way galaxy is rotating faster than scientists had thought and is half again more massive. That means it is not the little sister of the nearby, supposedly larger Andromeda Galaxy, but more like a fraternal twin. It's also more likely to collide with Andromeda in a few billion years.
"It's not going to be a hard collision," Reid said. "The galaxies are mostly empty. The distances between stars is big. We're not going to feel it."
But the gravitational chaos of two galaxies colliding could conceivably hurl Earth into the intergalactic void.
"Then we could look back and see what the Milky Way looks like," he said, putting a happy spin on the prospect of being exiled into intergalactic nothingness.
Despite all that's been discovered, the universe remains deeply enigmatic. Astronomers want to get a handle on the unseen dark matter, the existence of which is inferred from the motion of galaxies. They'd like to understand that dark-energy stuff — what is it, exactly? They'd like to know how galaxies formed, and why they tend to have black holes at their centers.
And, of course, the astronomers are hungry to find new planets. They have found more than 300 in the past decade — new worlds orbiting distant stars. Almost all are gas giants, very hot, even larger than Jupiter. The next great leap will be the discovery of small, rocky, Earth-like planets.
Eventually, said John Mather, a Nobel-laureate NASA scientist who has worked on the Webb telescope, "we will find planets, around other stars, that are alive."
A constant in the history of the telescope is that new instruments inevitably change our view of the cosmos. Another constant is that the Copernican model, in all its significance, continues to hold. There does not appear to be anything particularly special about our place in the universe.
"Life is sort of a small fraction of what the universe is about — depending on your perspective," said Adam Burrows, a Princeton astronomer. "If you look out in the universe, it's a pretty dead place. . . . Anyone coming from [Galileo's] time would be shocked by the diminution of mankind in the context of the universe."
But, he added, "Galileo would be less shocked than most."