Team of scientists painting better picture of universe

Team of scientists painting better picture of universe

The twinkle, twinkle of little stars may be fine for stargazers scanning for the Big Dipper or Orion's Belt.

But some University of Illinois scientists are helping create a better picture of the universe using light, and other celestial emissions, that you can't see just by looking up.

Astronomers You-Hua Chu, chair of the UI Astronomy Department, Robert Gruendl and Rosa Williams combine infrared, ultraviolet, X-ray and radio signals from the stars with the visible light we see using our eyes or traditional optical telescopes.

They're focused in particular on the Large and Small Magellanic Clouds, Earth's next-door neighbors galaxywise.

Next door is a relative term in this case. The closest galaxies to our own Milky Way are still 150,000 to 180,000 light years distant, or about 900 quadrillion miles for the former, around a quintillion for the latter.

"They look like big fuzzy patches to the unassisted eye," said Williams, and only in the Southern Hemisphere, where they're visible in the night sky, unlike around here. They were first recorded on Magellan's circumnavigation of the world in the early 1500s, hence the name.

Scientists have been studying the Magellanic Clouds for a long time with optical telescopes, notably the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory in Chile, yielding a detailed survey of the galaxies from a visible light perspective.

But stars don't emit visible light alone and looking at them that way in isolation is something like looking at the Mona Lisa in black and white.

Radio telescope data has been available for a few decades to help augment the picture. In recent years, however, NASA and others have given astronomers new ways to view the heavens.

That includes the Hubble Space Telescope, for example, and newer tools such as the Chandra X-Ray Observatory and the Spitzer Space Telescope, an Earth-orbiting satellite array that captures infrared light emissions, which was launched in 2003.

Chu, Gruendl and Williams presented some of the results of marrying such data to the optical survey of the Magellanic Clouds at the American Astronomical Society meeting in Washington, D.C., this month.

Chu used her laptop during an interview to show how adding the new viewpoints changes the picture of our galactic neighbors.

In the color-coded presentation, the visible light rendering of the galaxies, colored green for illustrative purposes, looks sparse on the screen. The picture gets fuller by adding X-ray data, done in blue, and infrared, in red.

The infrared light comes from newborn stars, which are clouded in a cocoon of dust at that point and emit little visible light. But it's hot inside the dust cloud and heat means infrared emissions. Think of using a night scope to look at nocturnal animals while on a photo safari.

The X-rays capture the aftermath of star deaths, causing clouds of super-heated gas to sweep through surrounding areas.

The UI researchers can make stunning visualizations from the combined data, which frequently end up in places such as Astronomy Picture of the Day and Hubble Heritage, popular Web-based space image collections.

"I was Miss July on the Chandra calendar," Gruendl joked.

The combined images also are giving scientists new insight into the workings of the universe. Star formation, for instance, may not be the discreet process it has been thought to be, but more of a continuous cycle, at least in the case of the Magellanic Clouds, Gruendl said.

The UI astronomers also are learning more about our own galaxy, as well as those much farther away, by getting a better picture of the nearby galaxies.

Chu likened studying the Milky Way from Earth to trying to count the olives on a pizza from inside it.

"It's just very hard to get a detailed handle on it because it is all around us," Gruendl said.

On the other hand, looking at the Magellanic Clouds from Earth is like standing over a pizza on the table and mentally cataloging its toppings. A viewpoint from outside makes it much easier, say, to pick out the anchovies, or stellar features that may be common to our solar system.

Likewise, the information can tell us something about Earth, whose formation appears to have resulted from stellar processes like those the UI scientists are studying, which may be reflected in its geology, Williams said.

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