This illustration provided by NASA's Spitzer Telescope Wednesday Feb. 8, 2006 compares the size of a gargantuan star and its surrounding dusty disk (top) to that of our solar system. Monstrous disks like this one were discovered around two "hypergiant" stars by NASA's Spitzer Space Telescope. Astronomers believe these disks might contain the early "seeds" of planets, or possibly leftover debris from planets that already formed. The hypergiant stars, called R 66 and R 126, are located about 170,000 light-years away in our Milky Way's nearest neighbor galaxy, the Large Magellanic Cloud. The stars are about 100 times wider than the sun, or big enough to encompass an orbit equivalent to Earth's. The plump stars are heavy, at 30 and 70 times the mass of the sun, respectively. They are the most massive stars known to sport disks. (AP Photo/NASA)

This image made in 2000 and released by NASA GSFC - Scientific Visualization Studio, shows Earth's city lights. This composite image was created with data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Originally designed to view clouds by moonlight, the OLS is also used to map the locations of permanent lights on the Earths surface. (AP Photo/NASA Goddard Space Flight Center - Scientific Visualization Studio, Craig Mayhew and Robert Simmon)

A computer composite image of North America shows the levels of luminance visible on the night of Aug. 10, 2001. The composite, created of multiple Earth-observing satellite images, shows that the brightest light comes from the more populated centers. (AP Photo/NASA Goddard Space Flight Center)

This image provided by NASA Thursday Nov. 2, 2006 is a recent photo from the Cassini spacecraft showing the mighty planet Saturn, and if you look very closely between its wing-like rings, upper left, revealed as a faint pinprick of light. That tiny dot is Earth bustling with life as we know it. The image is the second ever taken of our world from deep space. The first was captured by the Voyager spacecraft in 1990. This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. The mosaic images were acquired as the spacecraft drifted in the darkness of Saturn's shadow for about 12 hours, allowing a multitude of unique observations of the microscopic particles that compose Saturn's faint rings. (AP Photo/NASA/JPL)

This image released by NASA Thursday May 5, 2005 shows the Sombrero galaxy. The galaxy, called Messier 104, is commonly known as the Sombrero galaxy because in visible light it resembles a broad-brimmed Mexican hat called a sombrero. The new Sombrero picture combines a recent infrared observation from NASA's Spitzer Space Telescope with a well-known visible light image from NASA's Hubble Space Telescope. The Sombrero is one of the most massive objects at the southern edge of the Virgo cluster of galaxies. It is equal in size to 800 billion suns. This spiral galaxy is located 28 million light-years away and is 50,000 light-years across. Viewed from Earth, it is just six degrees away from its equatorial plane. (AP Photo/NASA)

The full moon turns red and orange as it passes the Space Needle in Seattle during a total lunar eclipse Wednesday evening, Oct. 27, 2004. With the Earth passing between the sun and the moon, the only light hitting the full moon was from the home planet's sunrises and sunsets, resulting in the orange and red hue. (AP Photo)

This undated image provided by the Smithsonian Institution showing streetlights on Earth at night, is part of an exhibit at the National Air and Space Museum in Washington entitled: Earth from Space. A dark blue layer was added to the image to show where land masses are located. European cities are especially bright, and in Egypt, lights glitter along the Nile. (AP Photo/Smithsonian)

Astronaut Dale A. Gardner, left, holds a "For Sale" sign, making light of the status of the retrieved communications satellite below in the cargo bay of the space shuttle Discovery, Nov. 1984. Astronaut John Allen IV stands on the end of the arm of the Remote Manipulator System. (AP Photo/NASA)

During the 15 years that the NASA/European Space Agency (ESA) Hubble Space Telescope has orbited the Earth, it has taken three-quarters of a million photos of the cosmos -- images that have awed, astounded and even confounded astronomers and the public alike. On Monday April 25, 2005, NASA and ESA released new views of two of the most well-known images Hubble has ever taken: the Eagle Nebula, and spiral galaxy M51(NGC5194), known as the Whirlpool Galaxy. The images, among the largest and sharpest views Hubble has ever taken, were made with the Advanced Camera for Surveys (ACS). The two new images are so incredibly sharp they could be enlarged to billboard size and still retain all of their stunning details. The new Whirlpool Galaxy image showcases the spiral galaxy's classic features, from its curving arms, where newborn stars reside, to its yellowish central core that serves as home for older stars. The graceful, winding arms of M51 are actually long lanes of stars and gas laced with dust. This sharpest-ever image, taken in January 2005, illustrates a spiral galaxy's grand design. Some astronomers believe that the Whirlpool's arms are so prominent because of the effects of a close encounter with NGC 5195, the small, yellowish galaxy at the outermost tip.

This photo supplied by NASA-ESA on Tuesday, May 15,2007, shows a ring of what NASA says is dark matter, which measures 2.6 million light-years across, which was found in the cluster ZwCl0024+1652, located 5 billion light-years from Earth. An internationalteam of astronomers using the Hubble Space Telescope has discovered the ghostly ring of dark matter that was formed long ago during a titanic collision between two massive galaxy clusters. It is the first time that a dark matter distribution has been found that differs substantially from the distribution of ordinary matter. Astronomers have long suspected the existence of the invisible substance of dark matter as the source of additional gravity that holds galaxy clusters together. Although astronomersdon't know what dark matter is made of, they hypothesize that it is a type of elementary particle that pervades the Universe. (AP Photo/NASA-ESA)

This image, taken by the NASA/ESA Hubble Space Telescope February 6, 2007, shows the planetary nebula NGC 2440 - the chaotic structure of the demise of a star, a colourful "last Hurray" of a star like our Sun. The star is ending its life by casting off its outer layer of gas, which formed a cacoon around the stars remaining core. Ultraviolet light from the dying star makes the material glow. The burned out star, called a white dwarf, is the white dot in the centre and is one of the hottest known with 200,000 degrees Celsius. Our Sun will eventually burn out and shroud itself with stellar debris, but not for another five billion years. The nebula's chaotic structure suggests that the star sheds its mass periodically. During each outburst, the star expelledmaterial in a different direction. This can be seen in the two bowtie-shaped lobes. The nebula is also rich in clouds of dust, some of which form long, dark streaks pointing away from the star. The NGC 2440 lies about 4,000 light-years away from earth. The material expelled by the star glows with different colours depending on its composition, its density and how close it is to the hot central star. Blue samples Helium, blue-green oxygen, and red nitrogen and hydrogen. (AP Photo/Hubble)

This photograph of the coil-shaped Helix Nebula, released Friday May 9, 2003, is one of the largest and most detailed celestial images ever made. The composite picture is a seamless blend of ultra-sharp images from NASA's Hubble Space Telescope combined with the wide view of the Mosaic Camera on the National Science Foundation's 0.9-meter telescope at Kitt Peak National Observatory near Tucson, Ariz. The image shows a fine web of filamentary "bicycle-spoke" features embedded in the colorful red and blue ring of gas. At 650 light-years away, the Helix is one of the nearest planetary nebulae to Earth. A planetary nebula is the glowing gas around a dying, Sun-like star. (AP Photo/NASA)

This composite photo by the Hubble Space Telescope, released Tuesday March 9, 2004 by NASA, a long-duration exposure, is the deepest-ever view of the universe, looks back to the edge of the big bang, and shows a chaotic scramble of odd galaxies smashing into each other and re-forming in bizarre shapes. The galaxies in this panel were plucked from a harvest of nearly 10,000 galaxies in the Ultra Deep Field, the deepest visible-light image of the cosmos. The image required 800 exposures taken over the course of 400 Hubble orbits around Earth. The total amount of exposure time was 11.3 days, taken between Sept. 24, 2003 and Jan. 16, 2004. (AP Photo/NASA)

This composite photo by the Hubble Space Telescope, released Tuesday March 9, 2004 by NASA, a long-duration exposure, is the deepest-ever view of the universe, looks back to the edge of the big bang, and shows a chaotic scramble of odd galaxies smashing into each other and re-forming in bizarre shapes. The galaxies in this panel were plucked from a harvest of nearly 10,000 galaxies in the Ultra Deep Field, the deepest visible-light image of the cosmos. The image required 800 exposures taken over the course of 400 Hubble orbits around Earth. The total amount of exposure time was 11.3 days, taken between Sept. 24, 2003 and Jan. 16, 2004. (AP Photo/NASA)