ABOUT THE SPITZER TELESCOPE: The Spitzer Space Telescope was launched on 25 August 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. Also, many molecules in space, including organic molecules, have their unique signatures in the infrared.
WHAT IS INFRARED LIGHT? Infrared radiation is an invisible form of light that we usually detect as heat, like the sun shining on our face, or the warmth of a campfire. It has all the same properties as visible light: for example, it can be focused and reflected. The only difference is that it has a longer wavelength, which means we can't see it with the naked eye. Light is made of tiny particles called photons, and the wavelength tells us how fast those particles are vibrating. The shorter the wavelength, the faster the particles are moving. Shorter light waves look blue, and longer ones look red. The wavelength of infrared light is so long that we can't see it at all. Any warm object gives off infrared radiation. By checking in the infrared spectrum, engineers can find heat leaks in buildings, doctors can find hidden tumors in the body, and biologists can locate diseased plants in a forest. Astronomers use infrared imaging to detect warm dust around new stars that are not yet "hot" enough to emit visible light.