THE FORMATION OF THE MOON: The Earth's moon formed just 30 to 50 million years after the sun was formed, when an object the size of Mars collided with Earth, and released a giant cloud of dust along with the moon. After examining a cluster of about 500 stars with the Spitzer Space Telescope, the researchers found very little evidence of collisions. If there had been such an event, large amounts of dust would have remained in the solar system long after the creation of a moon. The telescope would have indirectly observed pieces of dust that had absorbed light from the star in their solar system and become warmer than the surroundings.
ABOUT THE SPITZER TELESCOPE: The Spitzer Space Telescope was launched on August 25, 2003. Spitzer detects the infrared energy radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground. Spitzer allows us to peer into regions of space that are hidden from optical telescopes. Many areas of space are filled with vast, dense clouds of gas and dust that block our view. Infrared light however can penetrate these clouds, allowing us to peer into regions of star formation, the centers of galaxies, and into newly forming planetary systems. Infrared also brings us information about the cooler objects in space, such as smaller stars which are too dim to be detected by their visible light, extrasolar planets, and giant molecular clouds.