About the Spitzer Space Telescope n August 25, 2003, NASA launched the last in its “Great Other Legacy science programs include the following: OObservatories” series: The Spitzer Space Telescope. In FEPS (Formation and Evolution of Planetary Systems): an unusual orbit trailing Earth around the Sun, Spitzer’s two Michael Meyer of the University of Arizona will use Spitzer to cameras and other instruments are bringing unprecedented take pictures and study the light from high-resolution, sensitive observations about 300 Sun-like stars with disks, to the study of the infrared universe. ranging in age from a few million Given the achievements of its to a few billion years. “We’re going predecessor Great Observatories to trace the evolution of the disks (Compton Gamma-Ray Observatory, — the leftovers from star formation,” Hubble Space Telescope, and Chandra he says. X-ray Observatory), how does another major space telescope add to our GLIMPSE (Galactic Legacy Infrared astronomical understanding? Objects Mid-Plane Survey Extraordinaire): in space give off radiation at different Ed Churchwell of the University of wavelengths. To gain a complete Wisconsin will use Spitzer to trace picture of how any object behaves in the inner structure of the Milky space, astronomers need to study all Way by probing dusty areas of star of the radiation it gives off. Detecting formation. “With infrared, we can radiation at different wavelengths penetrate sections of the galaxy takes different technologies, and that are [otherwise] blind to us,” thus specialized telescopes. Compton Churchwell says. “The GLIMPSE studied the shortest wavelength survey will essentially see everything gamma-rays, and Chandra studied the there is to see in the [infrared] slightly longer X-rays. Hubble studied galaxy.” still-longer-wavelength visible light, SINGS (Spitzer Nearby Galaxies and Spitzer will study the still-longer infrared light. Survey): Robert Kennicutt of the University of Arizona will turn Infrared studies open windows on all kinds of processes in Spitzer’s infrared eyes on 75 of our nearest neighbor galaxies. the heavens, from the formation of stars and planets, to the He’ll compare his Spitzer infrared images to observations of structure of our own Milky Way and other galaxies, to the these galaxies at other wavelengths to determine how factors earliest formation of structure in the entire universe. like gas and dust content and the amounts of certain elements Many of the Spitzer science projects involve measurements contribute to galaxy evolution. of dust and its properties in molecular clouds, planet and star GOODS (Great Observatories Origins Deep Survey): Mark formation, or galaxies. Dickinson of the Space Telescope Science Institute will do A Legacy of New Knowledge from Spitzer Space Telescope an infrared survey of a famous patch of sky called the Hubble he Spitzer Legacy Science Program will allow the telescope Deep Field, a seemingly empty area near the Big Dipper. A deep Tto devote a lot of time to six big projects that will benefi t image of this “fi eld” with Hubble Space Telescope found it to the research of a wide range of astronomers. One of the Legacy be crowded with the most distant galaxies ever seen in optical programs is led by Neal Evans, an astronomer at The University light. Since then, this same fi eld has been studied with all kinds of Texas at Austin’s McDonald Observatory. His Legacy project of telescopes on the ground and in space, in many wavelengths. is called “From Molecular Cores to Planet-Forming Disks,” “This research has lots of implications on galaxy evolution and known as “cores to disks” or “c2d.” The c2d team is using cosmology,” Dickinson says. Spitzer to look at newly forming stars. The main idea behind the SWIRE (Spitzer Wide-area Infrared Extragalactic Survey): project, Evans says, “is to get as complete a sample as possible of Carol Lonsdale of the California Institute of Technology will regions that are forming stars like the Sun.” use Spitzer to perform a large sky survey, to catalog about “We’ll be surveying large areas of molecular clouds, to fi nd two million objects (mainly distant galaxies). She hopes to anything that will form a star or even something smaller,” he understand the connections between three different types of said. This range encompasses failed stars (called brown dwarfs). galaxies: starburst galaxies, which give off lots of radiation in The team will study the process from the earliest formation to the far infrared region; old galaxies called “spheroids,” which young stars that are surrounded by disks that may be forming are not forming stars; and galaxies with massive black holes at planets. their cores..