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ABOUT THE SPITZER TELESCOPE
The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope
Facility) was launched into space by a Delta rocket from Cape Canaveral,
Florida on 25 August 2003. During its mission, Spitzer will obtain images
and spectra by detecting the infrared energy, or heat, radiated by objects
in space between wavelengths of 3 and 180 microns (1 micron is one-millionth
of a meter). Most of this infrared radiation is blocked by the Earth's
atmosphere and cannot be observed from the ground.
Consisting of a 0.85-meter telescope and three cryogenically-cooled science
instruments, Spitzer is the largest infrared telescope ever launched into
space. Its highly sensitive instruments give us a unique view of the
Universe and allow us to peer into regions of space which are hidden from
optical telescopes. Many areas of space are filled with vast, dense clouds
of gas and dust which 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.
Because infrared is primarily heat radiation, the telescope must be cooled
to near absolute zero (-459 degrees Fahrenheit or -273 degrees Celsius) so
that it can observe infrared signals from space without interference from
the telescope's own heat. Also, the telescope must be protected from the
heat of the Sun and the infrared radiation put out by the Earth. To do this,
Spitzer carries a solar shield and will be launched into an Earth-trailing
solar orbit. This unique orbit places Spitzer far enough away from the Earth
to allow the telescope to cool rapidly without having to carry large amounts
of cryogen (coolant). This innovative approach has significantly reduced the
cost of the mission.
Spitzer will be the final mission in NASA's Great Observatories Program - a
family of four orbiting observatories, each observing the Universe in a
different kind of light (visible, gamma rays, X-rays, and infrared). Other
missions in this program include the Hubble Space Telescope (HST), Compton
Gamma-Ray Observatory (CGRO), and the Chandra X-Ray Observatory(CXO).
Spitzer is also a part of NASA's Astronomical Search for Origins Program,
designed to provide information which will help us understand our cosmic
roots, and how galaxies, stars and planets develop and form.
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.
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This web page was last updated on:
28 July, 2011
 
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