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Post by Deleted on May 26, 2013 9:03:58 GMT -8
 Hubble updated photo of the Ring Nebula.
The Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.
"The nebula is not like a bagel, but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in Nashville, Tenn. He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula.
This planetary nebula's simple, graceful appearance is thought to be due to perspective: our view from Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances with the coolest red gas along the outer boundary. Credit: NASA/Hubble Heritage Team
› Larger image "With Hubble's detail, we see a completely different shape than what's been thought about historically for this classic nebula," O'Dell said. "The new Hubble observations show the nebula in much clearer detail, and we see things are not as simple as we previously thought."
The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers.
Previous observations by several telescopes had detected the gaseous material in the ring's central region. But the new view by Hubble's sharp-eyed Wide Field Camera 3 shows the nebula's structure in more detail. O'Dell's team suggests the ring wraps around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring.
The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf is the stellar remnant of a sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally collapse to a compact object.
O'Dell's team was surprised at the detailed Hubble views of the dark, irregular knots of dense gas embedded along the inner rim of the ring, which look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The Hubble images have allowed the team to match up the knots with the spikes of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae.
All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size, becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow.
The outer rings were formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an hour, but the center is moving faster than the expansion of the main ring. O'Dell's team measured the nebula's expansion by comparing the new Hubble observations with Hubble studies made in 1998.
The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium.
Studying the Ring Nebula's fate will provide insight into the sun's demise in another 6 billion years. The sun is less massive than the Ring Nebula's progenitor star, so it will not have an opulent ending.
"When the sun becomes a white dwarf, it will heat more slowly after it ejects its outer gaseous layers," O'Dell said. "The material will be farther away once it becomes hot enough to illuminate the gas. This larger distance means the sun's nebula will be fainter because it is more extended."
In the analysis, the research team also obtained images from the Large Binocular Telescope at the Mount Graham International Observatory in Arizona and spectroscopic data from the San Pedro Martir Observatory in Baja California, Mexico.
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Post by Willing Sniper on May 26, 2013 9:20:51 GMT -8
That is truly amazing.
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Post by Deleted on May 26, 2013 9:31:58 GMT -8
Nebs a hottie.
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Post by Deleted on Jun 5, 2013 8:46:15 GMT -8
The Ring Nebula is one of the most famous celestial objects because of its delicate beauty. That shimmering oval of rainbow colors has popped up everywhere from dorm-room posters to book jackets to album covers to just about every TV backdrop in the history of sci-fi. But it is more than mere eye candy. The Ring is also fascinating for what it tells us about our future.
Middleweight stars like the sun expand and cool in their old age, briefly turning into red giants. After the red giant stage, the outer layers puff off, leaving behind a white dwarf: a dense, super-hot stellar cinder. Those puffed-out layers glow brightly before they disperse. That is exactly what we are seeing in this brand-new Hubble image of the Ring Nebula, along with the video interpretation of that image–a snapshot of what will happen to the sun as it runs out of nuclear fuel in about 5 billion years. The Hubble data also add a completely new twist to what astronomers know about the Ring. For the first time, researchers can get an accurate, three-dimensional understanding of the structure of the nebula.
Put that information together with other images taken using different filters and imaging techniques, and scientists have an incredibly detailed picture of how a sunlike star dies.
For comparison, I’ve collected a greatest-hits gallery of recent images of the Ring Nebula taken by other telescopes and satellites, each created using different techniques. You will notice that there is quite a bit of variation here: Most of these pictures little resemble the space-lollipop that has become an astronomy pop-culture staple. That is because the complexity of the nebula itself. It contains many types of atoms in many different states of ionization, each emitting in its own characteristic way. By choosing to zero in on a particular wavelength (or range of wavelengths) of radiation, astronomers can highlight specific elements, temperatures, and densities of the Ring Nebula.
Look at the Ring Nebula with your own eye through a good-size telescope (you’ll need at least 8″ of aperture under dark skies) and you will walk away with yet another impression. Because of the selective sensitivity of the human retina, the Ring Nebula will appear as a faint, diaphanous greenish-gray oval. That is a useful reminder that the colors of space are highly subjective. Each type of image is truthful in its own way, but none of them have a unique claim on representing what the Ring “really” looks like.
     
watch the video for the full story about the dying gasps of a sunlike star.
And be glad that all this action is all unfolding far away. Before the sun produces a beautiful nebula of its own, it will have either baked the Earth to a crisp or swallowed and digested our planet entirely. If any living things are around to see the sun’s version of the Ring Nebula, they will probably be watching from another star system many light years away.
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Post by Deleted on Jun 5, 2013 10:23:26 GMT -8
Gods eye. |
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Post by Willing Sniper on Jun 5, 2013 10:25:19 GMT -8
God's anus
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