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| Planetary Nebula IC 418 |
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An enormous glowing shell of gas envelopes the core stellar remnant that together make up the planetary nebula IC 418 about 2,000 light-years away in the constellation Lepus, the hare. The nebula, spanning about one-tenth of a light-year, was formed when its central star -- a red giant a few thousand years ago -- ejected its outer layers into space. The star's hot core floods the surrounding gas with ultraviolet radiation, causing it to glow like a fluorescent bulb. |
| Hubble Reveals the Heart of the Whirlpool Galaxy |
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| Hobby-Eberly Telescope |
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The Hobby-Eberly Telescope Dome and George T. Abell Gallery. |
| Biggest and Brightest |
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A star in a cluster near the center of our Milky Way galaxy may be the
largest and brightest ever found. Called LBV 1806-20, it’s five to 40
million times brighter than the Sun, at least 150 times as massive, and
about 200 times wider. Astronomers don’t know if it’s a single star, or if
it’s bound in a binary or triple star system. The star’s strange properties
pose a challenge to the current theory of star formation, according to the
star’s discoverer, Steve Eikenberry of the University of Florida in
Gainesville. [CREDIT: UNIVERSITY OF FLORIDA/MEGHAN KENNEDY] |
| Pole Stars Past, Present, and Future |
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Today, Polaris is the North Star or the “pole star.” All the stars in the northern hemisphere sky appear to rotate around it. But thousands of years ago, during the reign of the pharaohs, there was a different pole star: Thuban, in the constellation Draco, the dragon. That’s because the direction of north in the sky changes as Earth’s axis wobbles in a 26,000-year cycle. This causes the pole to aim at different stars over time, a process called precession. You can spot the pole star of the future, Vega, shining brightly high in the western sky on November nights. But it will be more than 10,000 years before Vega’s reign begins. |
| Supernova Layers |
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In the last moments of its life, a star destined to explode as a supernova has a structure like an onion, with layers of elements outside the iron core. The structure (not to scale) is depicted against this Hubble image of Betelgeuse, which will become a supernova within a few thousand years. |
| Kuiper Belt |
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The Kuiper Belt (blue dots) may contain millions of icy comets beyond the orbit of Neptune. Pluto is one of its largest members. |
| Aurora |
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The northern lights flash brilliant colors alongside Orion over the Missouri River (M. Hollingshead/Extreme Instability) |
| Lunar Phases |
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At the new Moon phase, the Moon is so close to the Sun in the sky that none of the side facing Earth is illuminated (position 1 in illustration). In other words, the Moon is between Earth and Sun. At first quarter, the half-lit Moon is highest in the sky at sunset, then sets about six hours later (3). At full Moon, the Moon is behind Earth in space with respect to the Sun. As the Sun sets, the Moon rises with the side that faces Earth fully exposed to sunlight (5). |
« First Images | « Previous Images | Retrieved 868 to 877 (of 877 total) images
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