All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet night last September, much of that night's auroras had died down. Suddenly though, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again. This time, unexpectedly, pareidoliacally, they created an amazing shape reminiscent of a giant phoenix. With camera equipment at the ready, two quick sky images were taken, followed immediately by a third of the land. The mountain in the background is Helgafell, while the small foreground river is called Kaldá, both located about 30 kilometers north of Iceland's capital Reykjavik. Seasoned skywatchers will note that just above the mountain, toward the left, is the constellation of Orion, while the Pleiades star cluster is also visible just above the frame center. The new aurora lasted only a minute and would be gone forever -- possibly dismissed as an embellished aberration -- were it not captured in the featured, digitally-composed, image mosaic. via NASA http://ift.tt/254533W
Wednesday, March 16, 2016
Monday, March 14, 2016
Dark Nebulas across Taurus
Sometimes even the dark dust of interstellar space has a serene beauty. One such place occurs toward the constellation of Taurus. The filaments featured here can be found on the sky between the Pleiades star cluster and the California Nebula. This dust is not known not for its bright glow but for its absorption and opaqueness. Several bright stars are visible with their blue light seen reflecting off the brown dust. Other stars appear unusually red as their light barely peaks through a column of dark dust, with red the color that remains after the blue is scattered away. Yet other stars are behind dust pillars so thick they are not visible here. Although appearing serene, the scene is actually an ongoing loop of tumult and rebirth. This is because massive enough knots of gas and dust will gravitationally collapse to form new stars -- stars that both create new dust in their atmospheres and destroy old dust with their energetic light and winds. via NASA http://ift.tt/1XpZlDN
Sunday, March 13, 2016
Neon Saturn
If seen in the right light, Saturn glows like a neon sign. Although Saturn has comparatively little of the element neon, a composite image false-colored in three bands of infrared light highlights features of the giant ringed planet like a glowing sign. At the most blue band of the infrared light featured, false-colored blue in the above image, Saturn itself appears dark but Saturn's thin rings brightly reflect light from our Sun. Conversely, Saturn's B ring is so thick that little reflected light makes it through, creating a dark band between Saturn's A and C rings. At the most red band of the infrared, false-colored red above, Saturn emits a surprisingly detailed thermal glow, indicating planet-wide bands, huge hurricane-like storms, and a strange hexagon-shaped cloud system around the North Pole. In the middle infrared band, false-colored green, the sunlit side of Saturn's atmosphere reflects brightly. The above image was obtained in 2007 by the robotic Cassini spacecraft orbiting about 1.6 million kilometers out from Saturn. via NASA http://ift.tt/1pgRg9s
Saturday, March 12, 2016
The Flash Spectrum of the Sun
In a flash, the visible spectrum of the Sun changed from absorption to emission on March 9 during the total solar eclipse. That fleeting moment, at the beginning the total eclipse phase, is captured by telephoto lens and diffraction grating in this image from clearing skies over Ternate, Indonesia. At left, the overwhelming light from the Sun is just blocked by the lunar disk. The normally dominant absorption spectrum of the solar photosphere is hidden. What remains, spread by the diffraction grating into the spectrum of colors to the right of the eclipsed Sun, are individual eclipse images. The images appear at each wavelength of light emitted by atoms along the thin visible arc of the solar chromosphere and in an enormous prominence extending beyond the Sun's upper limb. The brightest images, or strongest chromospheric emission lines, are due to Hydrogen atoms that produce the red hydrogen alpha emission at the far right and blue hydrogen beta emission to the left. In between, the bright yellow emission image is caused by atoms of Helium, an element only first discovered in the flash spectrum of the Sun. via NASA http://ift.tt/1pma33F
Friday, March 11, 2016
Lunar Shadow Transit
This snapshot from deep space captures planet Earth on March 9. The shadow of its large moon is falling on the planet's sunlit hemisphere. Tracking toward the east (left to right) across the ocean-covered world the moon shadow moved quickly in the direction of the planet's rotation. Of course, denizens of Earth located close to the shadow track centerline saw this lunar shadow transit as a brief, total eclipse of the Sun. From a spacebased perspective between Earth and Sun, the view of this shadow transit was provided by the Deep Space Climate Observatory (DSCOVR) spacecraft's Earth Polychromatic Imaging Camera (EPIC). via NASA http://ift.tt/1SFAY5M
Thursday, March 10, 2016
Dark Sun over Ternate
A dark Sun hangs in the clearing sky over a volcanic planet in this morning sea and skycape. It was taken during this week's total solar eclipse, a dramatic snapshot from along the narrow path of totality in the dark shadow of a New Moon. Earth's Indonesian isle of Ternate, North Maluku lies in the foreground. The sky is still bright near the eastern horizon though, beyond the region's flattened volcanic peaks and outside the Moon's umbral shadow. In fact, near the equator the dark lunar umbra is rushing eastward across Earth's surface at about 1,700 kilometers (1,100 miles) per hour. Shining through the thin clouds, around the Sun's silhouette is the alluring glow of the solar corona, only easily seen during totality. An inspiring sight for eclipse watchers, this solar corona is the tenuous, hot outer atmosphere of the Sun. via NASA http://ift.tt/1UVhhrg
Wednesday, March 9, 2016
Edge On Galaxy NGC 5866
Why is this galaxy so thin? Many disk galaxies are actually just as thin as NGC 5866, pictured above, but are not seen edge-on from our vantage point. One galaxy that is situated edge-on is our own Milky Way Galaxy. Classified as a lenticular galaxy, NGC 5866 has numerous and complex dust lanes appearing dark and red, while many of the bright stars in the disk give it a more blue underlying hue. The blue disk of young stars can be seen extending past the dust in the extremely thin galactic plane, while the bulge in the disk center appears tinged more orange from the older and redder stars that likely exist there. Although similar in mass to our Milky Way Galaxy, light takes about 60,000 years to cross NGC 5866, about 30 percent less than light takes to cross our own Galaxy. In general, many disk galaxies are very thin because the gas that formed them collided with itself as it rotated about the gravitational center. Galaxy NGC 5866 lies about 50 million light years distant toward the constellation of the Dragon (Draco). via NASA http://ift.tt/1LR5053
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