The image above is a wonderful example of the benefits of data gathered across multiple observatory missions. The image shows the Pinwheel Galaxy, also known as M101 (Messier 101). The image combines data in the infrared, visible, ultraviolet and X-rays. The data types were gathered from four different NASA space-based telescopes. This multi-spectral view shows that both young and old stars are evenly distributed along M101's tightly-wound spiral arms. Such composite images allow astronomers to see how features in one part of the spectrum match up with those seen in other parts. It is like seeing with a regular camera, an ultraviolet camera, night-vision goggles and X-ray vision, all at the same time.
The Pinwheel Galaxy is in the constellation of Ursa Major (also known as the Big Dipper). The Pinwheel is about 70 percent larger than our own Milky Way Galaxy, with a diameter of about 170,000 light years, and sits at a distance of 21 million light years from Earth. This means that the light we're seeing in this image left the Pinwheel Galaxy about 21 million years ago.
The hottest and most energetic areas in this composite image are shown in purple, where the Chandra X-ray Observatory observed the X-ray emission from exploded stars, million-degree gas, and material colliding around black holes.
The red colors in the image show infrared light, as seen by the Spitzer Space Telescope. These areas show the heat emitted by dusty lanes in the galaxy, where stars are forming.
The yellow component is visible light, observed by the Hubble Space Telescope. Most of this light comes from stars, and they trace the same spiral structure as the dust lanes seen in the infrared.
The blue areas are ultraviolet light, given out by hot, young stars that formed about one million years ago, captured by the Galaxy Evolution Explorer (GALEX).
Here are some quick facts about the subject:
- Object: NGC 5457, M101 / Messier 101, The Pinwheel Galaxy
- Coordinates (J2000): Right Ascention 14h 03m 12.59s, Declination +54° 20' 56.70''
- Distance Estimate: About 21 million light years
- Observation Dates: From 03/26/2000 through 01/01/2005 with 26 pointings
- Observation Time: A total of 274 hours (11 days 10 hours)
- Color Code: X-ray (Purple); Infrared (Red); Optical (Yellow); Ultraviolet (Blue)
And now, the mission particulars...
The Contributing Visible-Light Mission: The Hubble Space Telescope (HST) is a space telescope that was carried into orbit by the Space Shuttle Discovery in April 1990. HST is a 2.4-meter (7.9 ft) aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared. The telescope is named after the astronomer Edwin Hubble. HST was built by NASA, with contributions from the European Space Agency (ESA), and is operated by the Space Telescope Science Institute. The HST is one of NASA's Great Observatories, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope. The HST mission websites are: hubble.nasa.gov/ and asd.gsfc.nasa.gov/archive/hubble/ and hubblesite.org/
The Contributing X-ray Mission: The Chandra X-ray Observatory is a satellite launched July 1999 by Space Shuttle Columbia. Chandra is named in honor of Indian physicist Subrahmanyan Chandrasekhar who is known for determining the maximum mass for white dwarfs. "Chandra" also means "moon" or "luminous" in Sanskrit. Prior to launch, Chandra was known as AXAF, the Advanced X-ray Astrophysics Facility. Chandra was assembled and tested by TRW (now Northrop Grumman Aerospace Systems) in Redondo Beach, California. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, due primarily to the high angular resolution of the Chandra mirrors. The mission website is: chandra.harvard.edu/
The Contributing Infrared Mission: The Spitzer Space Telescope (SST) was launched August 2003 aboard a Delta II rocket. Spitzer is an infrared space observatory, the fourth and final of the NASA Great Observatories program. The observatory was renamed in honor of Lyman Spitzer, one of the 20th century's great scientists. The mission website is: www.spitzer.caltech.edu/
The Contributing Ultraviolet Mission: NASA's Galaxy Evolution Explorer (GALEX) is an orbiting ultraviolet space telescope launched on April 28, 2003. A Pegasus rocket placed the craft into a nearly circular orbit at an altitude of 697 kilometres (433 mi) and an inclination to the Earth's equator of 29 degrees. In February 2011 NASA stopped missions operation funding because of budget priorities. In May 2012, GALEX operations were transferred to the California Institute of Technology (Caltech). The mission website is: www.galex.caltech.edu/