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In 1609, Galileo improved the newly invented telescope, turned it toward
the heavens, and revolutionized our view of the universe. In celebration
of the 400th anniversary of this milestone, 2009 has been designated as
the International Year of Astronomy.
Today, NASA's Great Observatories are continuing Galileo's legacy with
stunning images and breakthrough science from the Hubble Space Telescope,
the Spitzer Space Telescope, and the Chandra X-ray Observatory.
While Galileo observed the sky using visible light seen by the human eye,
technology now allows us to observe in many wavelengths, including
Spitzer's infrared view and Chandra's view in X-rays. Each wavelength
region shows different aspects of celestial objects and often reveals new
objects that could not otherwise be studied.
This image of the spiral galaxy Messier 101 is a composite of views from
Spitzer, Hubble, and Chandra.
- The red color shows Spitzer's view in infrared light. It highlights
the heat emitted by dust lanes in the galaxy where stars can form.
- The yellow color is Hubble's view in visible light. Most of this light
comes from stars, and they trace the same spiral structure as the dust
lanes.
- The blue color shows Chandra's view in X-ray light. Sources of X-rays
include million-degree gas, exploded stars, and material colliding around
black holes.
Such composite images allow astronomers to see how features seen in one
wavelength match up with those seen in another wavelength. It's like
seeing with a camera, night vision goggles, and X-ray vision all at once.
In the four centuries since Galileo, astronomy has changed dramatically.
Yet our curiosity and quest for knowledge remain the same. So, too, does
our wonder at the splendor of the universe.
The International Year of Astronomy Great Observatories Image Unveiling is
supported by the NASA Science Mission Directorate Astrophysics Division.
The project is a collaboration between the Space Telescope Science
Institute, the Spitzer Science Center, and the Chandra X-ray Center.