Hubble’s Galaxy Gallery Hubble’s Galaxy Gallery Hubble’s Galaxy Gallery Definitions Hubble reached back 10 billion years Galaxy: Huge, swirling cities of millions to capture a view of young, never- or billions of stars, gas, and dust that are before-seen galaxies in various stages held together by gravity. of evolution. Called the Hubble Deep SPACE TELESCOPE Spiral: A galaxy with spiral arms, which Field, this view shows the dimmest, SCIENCE european space agency INSTITUTE wind out from near the galaxy’s center. most distant objects in the universe. Operated for NASA by AURA Most are about four billion times The arms are composed of gas, dust, and fainter than can be seen by the human young stars. Our Sun is a star in the eye. Besides uncovering the classical spiral Milky Way Galaxy. spiral and elliptical-shaped galaxies, Elliptical: A galaxy that is shaped like a Hubble found a bewildering football and contains mainly old stars assortment of other galaxy shapes and with little gas or dust. sizes that may yield important clues to the evolution of the universe. Some Light-year: The distance light travels × 12 of the galaxies may have formed less in a year (6 10 or 5 trillion 900 than one billion years after the Big billion miles). Bang, the initial cosmic explosion that many scientists believe jump-started Fast Facts the universe. Scientists will use the Location deep field image to test theories of In the constellation Ursa Major galaxy formation. (Big Dipper) Images from Deep Space Distance from Earth The Hubble Deep Field represents a The nearest galaxies are about 2.5 narrow view of the universe, covering billion light-years; the farthest, about a speck of sky. Essentially a narrow, 10.5 billion light-years. deep “core sample” of sky, the field Size is similar to a geologic core sample The galaxies vary in diameter from about of the Earth’s crust. Just as a core 3,000 to 55,000 light-years. sample represents a history of the evolution of the Earth’s surface, the Hubble Deep Field image contains Count the galaxies yourself, go to the information about the universe at “Hubble Deep Field Academy ” at many different stages in time. Unlike a geologic sample, scientists cannot amazing-space.stsci.edu measure the precise ages and dis- tances of all the galaxies in the image. Using large ground-based telescopes, About the Image they have measured distances to the Hubble produced the image shown on the front by observing nearly continuously Electronic Address 100 brightest galaxies. For the for 10 days. This image represents the longest Hubble exposure yet taken. You can get images and other information remaining several thousand galaxies, The telescope used three different filters to obtain this natural color image. about the Hubble Space Telescope on the scientists are using galaxy size and (Astronomers prefer to use the negative image (above) for analysis, because the World Wide Web: color, and theories and statistics to details of celestial objects are easier to see.) estimate their distance. hubble.stsci.edu

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