Friday, August 14, 2009
Black hole
Black holes represent some of the most extreme environments in the Universe; places where even light can not escape! In this show, you'll learn all about what makes a black hole tick, where they come from, and why a black hole has no hair!
Satellite galaxy
The Milky Way Galaxy has a number of satellite galaxies, which are showed in the illustration and table below. (See individual entries for more details on these galaxies.)
Satellite galaxies of the Milky Way | ||||
---|---|---|---|---|
galaxy | distance (light-years) | discovered | absolute magnitude | diameter (light-years) |
Canis Major Dwarf | 25,000 | 2003 | - | - |
Sagittarius Dwarf Elliptical | 78,000 | 1994 | -13.4 | >10,000 ? |
Large Magellanic Cloud | 160,000 | prehistoric | -18.1 | 20,000 |
Small Magellanic Cloud | 180,000 | prehistoric | -16.2 | 15,000 |
Ursa Major II | 200,000 | 2006 | - | - |
Ursa Minor Dwarf | 220,000 | 1954 | -8.9 | 1,000 |
Draco Dwarf | 270,000 | 1954 | -8.8 | 500 |
Sculptor Dwarf | 285,000 | 1938 | -11.1 | 1,000 |
Sextans Dwarf | 290,000 | 1990 | -9.5 | 3,000 |
Carina Dwarf | 330,000 | 1977 | -9.3 | 500 |
Fornax Dwarf | 450,000 | 1938 | -13.2 | 3,000 |
Leo I | 670,000 | 1950 | -9.6 | 500 |
Leo II | 830,000 | 1950 | -11.9 | 1,000 |
The milky way galaxy
In 2008, it was announced that infrared images from NASA's Spitzer Space Telescope have shown that the Milky Way's elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to have four major arms. Image credit: NASA/JPL-Caltech |
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An older map of the Milky Way Galaxy showing four major arms, with the Sun located in a region called the Orion Arm or Local Spur. Image credit: NASA |
Recent estimates put the total mass of the Milky Way Galaxy in the range one to two trillion solar masses, including a large but uncertain amount of dark matter in the dark halo. The Milky Way is the second largest member of the Local Group, after the Andromeda Galaxy.
picture of the universe
A collection of images representing some of the most impressive views in our universe. Included are the Orion Nebula, a dying star, spiral galaxy, birth of a star, the Eagle Nebula, extrasolar planet, a galaxy pair and the Cartwheel Galaxy. Many of these are false-color images, enhanced to yield an artistic view.
Spiral Galaxy: The magnificent M81 spiral galaxy takes center stage in this ultraviolet image from NASA's Galaxy Evolution Explorer. Young stars appear as wisps of bluish-white swirling around a central golden glow, which comes from a group of much older stars. The large fluffy bluish-white material to the left of M81 is a neighboring galaxy called Homberg IX. This galaxy is practically invisible to the naked human eye. However, when viewed in ultraviolet light, a region that is actively forming young stars is revealed. Image and caption by NASA. |
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