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Here's Looking at You, Universe

"The Webb is going to blow us away in the way the Hubble has blown us away," predicts Matt Mountain, director of the Space Telescope Science Institute in Baltimore. "We're going to penetrate the infrared in a way we've never done before. The Webb will send us very high-resolution infrared images of the Dark Ages of the universe, when galaxies were forming, when the first stars were forming."

Edwin Hubble and Milton Humason cracked part of the cosmic code in the 1920s when they discovered, using the 100-inch telescope on Mount Wilson near Pasadena, Calif., that the mysterious nebulae observed for hundreds of years were actually galaxies outside our own Milky Way. Moreover, their light indicated that all these galaxies were racing away from one another. The universe, we learned, isn't static. It's expanding. The astonishing implication is that, long ago, the entire universe was compressed into an infinitely dense point.

Fast-forward to 1998: The Hubble Space Telescope is studying extremely distant supernovae. Something is out of whack. The expansion of the universe, scientists realize, isn't steady as she goes; rather, it's accelerating. The new interpretation is that about 70 percent of the universe's overall energy budget is composed of a mysterious "dark energy." Meanwhile, 25 percent of the universe is "dark matter" -- another mystery. So we've got about 5 percent of the universe in the form of ordinary matter that we can stick into what physicists call the Standard Model. Obviously, there's more work to be done.

Two decades ago, the entire space astronomy program at NASA consisted of a single telescope called the International Ultraviolet Explorer. It had an 18-inch mirror. Since then, we've seen the deployment not only of the Hubble but also of such "Great Observatories" as the Chandra, the Compton and the Spitzer, and smaller telescopes such as COBE and WMAP. These instruments look at the universe in different wavelengths; combine the images and you get amazing pictures that something like the Hubble alone couldn't make.

The next huge step would be to see an extrasolar planet directly -- not merely infer its existence from wobbles and quirks in a star's light.

"We know how to do this," said Ron Polidan, chief architect for civil space for Northrop Grumman. "It's going to be hard. It's going to take a lot of effort. But there's no magic involved."

What's involved is a sun shade. It would be something that looked a bit like a daisy, maybe 10 or 20 meters across. It would need a propulsion system so that it could maneuver in space about 30,000 miles from the Webb. It would be, for the Webb, like a thumb held at a distance, blocking the light from a star. An occultor is what you call it. The idea is to cover the starlight so precisely that any planets orbiting that star could still be visible.

Then we could look for the signature of oxygen, ozone, carbon dioxide, nitrogen, maybe even chlorophyll. Or perhaps we'd see signs of car exhaust. Smog. We'd know that getting stuck in traffic is a cosmic fact of life.

Now let's go back to that exploding star, our friend Eta Carinae. Obviously, we shouldn't sink a lot of money into space telescopes if we're about to be annihilated. But here's what telescopes tell us: Eta Carinae has already spewed forth two huge lobes of material. They're not coming our way. Additional jets of star stuff will follow the same trajectory, predicts astrophysicist Mario Livio of the Space Telescope Science Institute. Besides, Eta Carinae is 7,500 light years away; that's a pretty long hike. So don't worry. It looks like the Death Star doesn't have our number.

But we should keep our eyes open. A telescope is, after all, an artificial eyeball. Our eyes and brain capture and analyze electromagnetic radiation in a portion of the spectrum that we self-referentially call "visible light." With telescopes, we have Superman vision. We have X-ray eyes and can see radio waves. Light at all these wavelengths is essentially immortal; a photon can travel from one side of the universe to the other without flagging.

The secrets of the cosmos are coming at us. All we have to do is look.

achenbachj@washpost.com

Joel Achenbach is a Washington Post

staff writer. He blogs at www.washingtonpost.com/achenblog.


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