Leonids Over Monument Valley


There was a shower over Monument Valley — but not water. Meteors. The featured image — actually a composite of six exposures of about 30 seconds each — was taken in 2001, a year when there was a very active Leonids shower. At that time, Earth was moving through a particularly dense swarm of sand-sized debris from Comet Tempel-Tuttle, so that meteor rates approached one visible streak per second. The meteors appear parallel because they all fall to Earth from the meteor shower radiant — a point on the sky towards the constellation of the Lion (Leo). The yearly Leonids meteor shower peaks again this week. Although the Moon’s glow should not obstruct the visibility of many meteors, this year’s shower will peak with perhaps 15 meteors visible in an hour, a rate which is good but not expected to rival the 2001 Leonids. By the way — how many meteors can you identify in the featured image?

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151115.html
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Wright Mons on Pluto


Long shadows are cast by a low Sun across this rugged looking terrain. Captured by New Horizons, the scene is found just south of the southern tip Sputnik Planum, the informally named smooth, bright heart region of Pluto. Centered is a feature provisionally known as Wright Mons, a broad, tall mountain, about 150 kilometers across and 4 kilometers high, with a 56 kilometer wide, deep summit depression. Of course, broad mountains with central craters are found elsewhere in the Solar System, like Mauna Loa on planet Earth and Olympus Mons on Mars. In fact, New Horizons scientists announced the striking similarity of Pluto’s Wright Mons, and nearby Piccard Mons, to large shield volcanoes strongly suggests the two could be giant cryovolcanoes that once erupted molten ice from the interior of the cold, distant world.

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151114.html
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The Tadpoles of IC 410


This telescopic close-up shows off the otherwise faint emission nebula IC 410. It also features two remarkable inhabitants of the cosmic pond of gas and dust below and right of center, the tadpoles of IC 410. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars. Formed in the interstellar cloud a mere 4 million years ago, the intensely hot, bright cluster stars energize the glowing gas. Composed of denser cooler gas and dust, the tadpoles are around 10 light-years long and are likely sites of ongoing star formation. Sculpted by winds and radiation from the cluster stars, their heads are outlined by bright ridges of ionized gas while their tails trail away from the cluster’s central region. IC 410 lies some 10,000 light-years away, toward the nebula-rich constellation Auriga.

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151113.html
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Kenya Morning Moon, Planets and Taurid


On November 8, a waning crescent Moon joined the continuing parade of planets in Earth’s early morning skies. Captured here from Amboseli National Park, Kenya, even the overexposed moonlight can’t washout brilliant Venus though, lined up near the ecliptic plane with faint Mars and bright Jupiter above. As if Moon and planets aren’t enough, a comparably bright Taurid meteor also streaks through the scene. In fact November’s Taurid meteor showers have had a high proportion of bright fireballs. Apparently streaming from radiants in Taurus, the meteors are caused by our fair planet’s annual passage through debris from Comet 2P/Encke. The comet’s dust grains are catching up with Earth’s atmosphere at a relatively low speed of about 27 kilometers per second.

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151112.html
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An Unexpected Rocket Plume over San Francisco


What is that unusual light in the sky? A common question, this particular light was not only bright but moving and expanding. It appeared just as the astrophotographer and his friend were photographing the Golden Gate Bridge in San Francisco, California against a more predictable night sky. They were not alone in seeing this unusual display — at least hundreds of people in California reported a similar sight. The consensus of experienced sky observers was that the plume resulted from a rocket launch — an explanation that was soon confirmed as an unpublicized test of a submarine-launched, unarmed, Trident II D5 nuclear missile. Such tests are not uncommon but do not usually occur just after sunset near a major metropolitan area — when they are particularly noticeable to many people. Were plume images not posted to the Internet and quickly identified, such a sky spectacle might have been understood by some to be associated with more grandiose — but incorrect — explanations.

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151111.html
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AE Aurigae and the Flaming Star Nebula


Is star AE Aurigae on fire? No. Even though AE Aurigae is named the flaming star, the surrounding nebula IC 405 is named the Flaming Star Nebula, and the region appears to have the color of fire, there is no fire. Fire, typically defined as the rapid molecular acquisition of oxygen, happens only when sufficient oxygen is present and is not important in such high-energy, low-oxygen environments such as stars. The material that appears as smoke is mostly interstellar hydrogen, but does contain smoke-like dark filaments of carbon-rich dust grains. The bright star AE Aurigae, visible toward the right near the nebula’s center, is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, light is emitted, as seen in the surrounding emission nebula. Pictured above, the Flaming Star nebula lies about 1,500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151110.html
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A Quadruple Sky Over Great Salt Lake


This was a sky to show the kids. All in all, three children, three planets, the Moon, a star, an airplane and a mom were all captured in one image near Great Salt Lake in Utah, USA in early September of 2005. Minus the airplane and the quadruple on the ground, this busy quadruple coincidence sky was visible last week all over the world. The easiest object to spot is the crescent Moon, which is easily the brightest sky orb in the featured image. Venus is the highest planet in the sky, with Jupiter to its right. The bright star Spica completes the quadruple just below Venus. The streak on the far right is an airplane. Mom is seated. Grandpa, appreciating the beauty of the moment, took the picture. This week, the pre-dawn sky shows a similar conjunction of planets.

from NASA http://antwrp.gsfc.nasa.gov/apod/ap151108.html
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