Infrared Camera Sees Through Stardust to the Edge of the Universe

SCIENCE THURSDAY -- April 19, 2012 at 1:30 PM EDT

Infrared Camera Sees Through Stardust to the Edge of the Universe

Space tornadoes, stellar nurseries, primitive galaxies - these are just a few of the dazzling images captured by the Spitzer Space Telescope since its 2003 launch. This week, NASA posted a collection of image highlights online. View the images in this slide show below:

While the Hubble Space Telescope only sees a narrow spectrum of visible light, Spitzer's Infrared Array Camera, or IRAC, sees in the infrared, which is primarily heat radiation. In space, any object with a temperature above absolute zero radiates in infrared light.

Since its 2003 launch, IRAC has proved to be resilient. Spitzer's three instruments required cooling with liquid helium to operate. In 2009 the liquid helium coolant was exhausted.

But the cold vacuum of space has kept the camera running longer than predicted. "We never expected much beyond the cryogenic mission," said Giovanni Fazio, principal investigator for IRAC at the Smithsonian Astrophysical Observatory. "It's quite a surprise that it's still functioning."

It's been running in this "warm phase" for 1,000 days now.

Stars are often born behind a thick veil of dust, which makes visible light cameras blind to the early star embryos. But Spitzer's camera can peer through dust clouds, allowing scientists to study star birth and formation, Fazio said.

They can also peer far back in time and space to distant galaxies formed just after the Big Bang. IRAC has photos of galaxies that were formed when the universe was 700 million years old - that's nearly newborn. As the universe expands, those ancient galaxies move faster and faster. Light at visible wavelengths that travel from those galaxies to our telescopes stretch during the journey, reaching the infrared part of the spectrum by the time it reaches us..

Spitzer can continue to operate for many more years, but eventually its days are numbered, Fazio said. At 97 million miles from Earth and drifting - too far to send a graduate student to replace that empty helium tank - Spitzer faces risks. Heat from the sun could damage the sensitive equipment, or it may drift too far for its radio signals to reach Earth.

Until IRAC stops functioning, however, scientist will remain busy analyzing the images it beams back.

"Every time you look at a different part of the spectrum, you see the universe in different ways," Fazio said.

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