Perhaps the most revolutionary and surprising Spitzer finds involve planets around other stars, called exoplanets. In 2005, Spitzer detected the first photons of light from an exoplanet. In a clever technique, now referred to as the secondary-eclipse method, Spitzer was able to collect the light of a hot, gaseous exoplanet and learn about its temperature. Later detailed studies revealed more about the composition and structure of the atmospheres of these exotic worlds.
"The performance of the two short wavelength channels of Spitzer's Infrared Array Camera is essentially unchanged from what it was before the observatory's liquid helium was exhausted," said Doug Hudgins, the Spitzer program scientist at NASA Headquarters in Washington. "To put that in perspective, that means Spitzer's sensitivity at those wavelengths is still roughly the same as a 30-meter ground-based telescope. This breathtaking image demonstrates Spitzer will continue to deliver world-class imagery and science during its warm mission."
The first of three images shows a cloud bursting with stars in the Cygnus region of our Milky Way galaxy. Spitzer's infrared eyes peer through and see dust, revealing young stars tucked in dusty nests. A second image shows a nearby dying star, a planetary nebula called NGC 4361, which has outer layers that expand outward in the rare form of four jets. The last picture is of a classic spiral galaxy called NGC 4145, located approximately 68 million light-years from Earth.
"With Spitzer's remaining shorter-wavelength bands, we can continue to see through the dust in galaxies and get a better look at the overall populations of stars," said Robert Hurt, imaging specialist for Spitzer at NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "All stars are equal in the infrared."
The galaxy, called NGC 1097, is located 50 million light-years away. It is spiral-shaped like our Milky Way, with long, spindly arms of stars. The "eye" at the center of the galaxy is actually a monstrous black hole surrounded by a ring of stars. In this color-coded infrared view from Spitzer, the area around the invisible black hole is blue and the ring of stars, white.
The black hole is huge, about 100 million times the mass of our sun, and is feeding off gas and dust along with the occasional unlucky star. Our Milky Way's central black hole is tame in comparison, with a mass of a few million suns.
The ring around the black hole is bursting with new star formation. An inflow of material toward the central bar of the galaxy is causing the ring to light up with new stars.
The galaxy's red spiral arms and the swirling spokes seen between the arms show dust heated by newborn stars. Older populations of stars scattered through the galaxy are blue. The fuzzy blue dot to the left, which appears to fit snuggly between the arms, is a companion galaxy. Astronomers say it is unclear whether this companion poked a hole in the larger galaxy, or just happens to be aligned in a gap in the arms. Image credit: NASA/JPL-Caltech
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