Tuesday, February 17, 2015

Everything About Kepler-432b is Extreme, Especially the Way it’s Going to Die

Everything About Kepler-432b is Extreme, Especially the Way it’s Going to Die:



Illustration of the orbit of Kepler-432b (inner, red) in comparison to the orbit of Mercury around the Sun (outer, orange). Credit: Dr. Sabine Reffert.


Illustration of the orbit of Kepler-432b (inner, red) in comparison to the orbit of Mercury around the Sun (outer, orange). Credit: Dr. Sabine Reffert.
Astronomers are calling Kepler-432b a ‘maverick’ planet because everything about this newly found exoplanet is an extreme, and is unlike anything we’ve found before. This is a giant, dense planet orbiting a red giant star, and the planet has enormous temperature swings throughout its year. In addition to all these extremes, there’s another reason you wouldn’t want to live on Kepler 432b: its days are numbered.

“In less than 200 million years, Kepler-432b will be swallowed by its continually expanding host star,” said Mauricio Ortiz, a PhD student at Heidelberg University who led one of the two studies of the planet. “This might be the reason why we do not find other planets like Kepler-432b – astronomically speaking, their lives are extremely short.”


Kepler-432b is one of the densest and massive planets ever found. The planet has six times the mass of Jupiter, but is about the same size. The shape and the size of its orbit are also unusual, as the orbit is very small (52 Earth days) and highly elongated. The elliptical orbit brings Kepler-432b both incredibly close and very far away from its host star.

“During the winter season, the temperature on Kepler-432b is roughly 500 degrees Celsius,” said Dr. Sabine Reffert from the Königstuhl observatory, which is part of the Centre for Astronomy. “In the short summer season, it can increase to nearly 1,000 degrees Celsius.”

Dr. Davide Gandolfi, also from the Königstuhl observatory, said that the star Kepler-432b is orbiting has already exhausted the nuclear fuel in its core and is gradually expanding. Its radius is already four times that of our Sun and it will get even larger in the future.

While Kepler-432b was previously identified as a transiting planet candidate by the NASA Kepler satellite mission, two research groups of Heidelberg astronomers independently made further observations of this rare planet, acquiring the high-precision measurements needed to determine the planet’s mass. Both groups of researchers used the 2.2-metre telescope at Calar Alto Observatory in Andalucía, Spain to collect data. The group from the state observatory also observed Kepler-432b with the Nordic Optical Telescope on La Palma (Canary Islands).

The results of this research were published in Astronomy & Astrophysics.

Source: University of Heidelberg

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Catch a ‘Conjunction Triple Play’ on February 20th as the Moon Meets Venus & Mars

Catch a ‘Conjunction Triple Play’ on February 20th as the Moon Meets Venus & Mars:



The Moon passes Mars and Venus last month... this week's pass is much closer! (Photo by Author).


The Moon passes Mars and Venus last month… this week’s pass is much closer! (Photo by author).
Fear not, the chill of late February. This Friday gives lovers of the sky a reason to brave the cold and look westward for a spectacular close triple conjunction of the planets Mars, Venus and the waxing crescent Moon.

This week’s New Moon is auspicious for several reasons.  We discussed the vagaries of the Black Moon of February 2015 last week, and the lunacy surrounding the proliferation of the perigee supermoon. And Happy ‘Year of the Goat’ as reckoned on the Chinese luni-solar calendar, as this week’s New Moon marks the start of the Chinese New Year on February 19th. Or do you say Ram or Sheep? Technical timing for the New Moon is on Wednesday, February 18th at 23:47 UT/6:47 PM EST, marking the start of lunation 1140. The next New Moon on March 20th sees the start of the first of two eclipse seasons for 2015, with a total solar eclipse for the high Arctic. More on that next month!



Stellarium


Looking west on the evening of February 20th. Credit: Stellarium.
And today also marks Shrove Tuesday and the start of Lent, as reckoned 47 days prior to Easter Sunday. In Western Christianity, Easter falls on the first Sunday past the first Full Moon past March 21st. This is the demarcation date set for the March Equinox, which actually falls on March 20th this year. Such is the wonderful world of calendars and astronomy, as the struggle to keep recorded versus actual observed time in sync continues.



Credit and Copyright


The dawn crescent Moon paired with Venus on February 26th, 2014. Credit and Copyright: Efrain Morales.
The first sighting opportunities for the slim waxing crescent Moon will come Thursday night on February 19th. And don’t miss the main event on Friday, February 20th when Mars, Venus and the two day old waxing crescent Moon all fit within a two degree diameter circle — about four Full Moon diameters — prior to sunset.  You can’t miss brilliant Venus, shining at -4th magnitude as the 3rd brightest natural object in the sky next to the Sun and the Moon. Through a telescope, Venus presents an  88% illuminated disk 12” in size and growing, while Mars shines at +1.3 magnitude and is just 4.2” in size. The closest conjunction of Venus and Mars actually occurs just 48 hours later, when they both fit within a 30’ field of view on the evening of Sunday, February 21st.



February 21st 01 UT


The Moon, Venus and Mars February 21st at 01:00 UT. (Credit: Starry Night).
The Moon is 2.37 days old and will appear 5 % illuminated during the Friday conjunction, and together, the trio will resemble a skewed emotion smiley face… think ‘:?’. Manage to catch a time exposure of one of the numerous ISS passes near the Mars/Venus conjunction this week and you could nab a unique ‘:/’ alignment!

Venus spends the first half of 2015 as a brilliant dusk object before heading for solar conjunction on August 15th, after which it once again passes into the dawn sky.  2015 is an “opposition-less” in-between year for Mars, as it reaches solar conjunction on the far side of the Sun on June 14th before making its slow comeback in the dawn sky. Expect the Red Planet to reach a favorable opposition next on May 22nd 2016.



tri-conjunction


Getting closer…  Venus and Mars as seen from Venezuela on the evening of February 16th. (Credit and Copyright: Jose Rozada @jmrozada).
Notice that this week’s tri-conjunction occurs very near the equinoctial point where the celestial equator and the plane of the ecliptic meet. This is the position that the Sun will occupy a month from now when the equinox total solar eclipse occurs.

Want more? One evening later on February 21st, the waxing crescent Moon will actually occult the +5.9 magnitude planet Uranus in the dusk sky for eastern North American observers:



Occult 4.0


The path of the February 21st occultation of Uranus by the Moon. Credit: Occult 4.0
This is occultation number 8 in a current cycle of 19 of Uranus by the Moon.  And there’s another pass of the Moon in front of the Hyades on February 25th as it occults the bright star Aldebaran for a second time in 2015 as seen from Scandinavia.



Aldebaran Occ


The path of the February 25th occultation of Aldebaran by the Moon. Credit: Occult 4.0.
Now for the ‘wow’ factor. The Moon lies just over a light second away at 357,000 kilometres distant. This week, Venus sits 1.4 AUs/ 11.6 light minutes away at 217 million kilometres distant, while Mars is 2.2 AUs/ 18.3 light minutes away at 341 million kilometres distant.

And from the surface of Mars, you’d see a brilliant conjunction of -1.3 magnitude Earth and -1.6 magnitude Venus just one degree in separation, with the +2.5 magnitude Moon nearby.



Venus and Earth rising as seen from the surface of Mars.


Venus and Earth rising as seen from the surface of Mars. Credit: Starry Night Education Software.
Perhaps Curiosity will nab this extraterrestrial spectacle, as Earthbound sky watchers gaze back this weekend!



About 

David Dickinson is an Earth science teacher, freelance science writer, retired USAF veteran & backyard astronomer. He currently writes and ponders the universe from Tampa Bay, Florida.

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Nobody Knows What These Mysterious Plumes are on Mars

Nobody Knows What These Mysterious Plumes are on Mars:



In the Journal Nature, astronomers deliver an exhaustive study of limited albeit high quality ground-based observations of Mars and come up short. A Martian mystery remains. What caused the extremely high-altitude plumes on Mars? (Credit: Nature, Sánchez-Lavega, A. et al. Feb 16, 2015, Figures 1a, 2)


In the Journal Nature, astronomers deliver an exhaustive study of limited albeit high quality ground-based observations of Mars and come up short. A Martian mystery remains. What caused the extremely high-altitude plumes on Mars? (Credit: Nature, Sánchez-Lavega, A. et al. Feb 16, 2015, Figures 1a, 2)
In March 2012, amateur astronomers began observing unusual clouds or plumes along the western limb of the red planet Mars. The plumes, in the southern hemisphere rose to over 200 kilometers altitude persisting for several days and then reappeared weeks later.

So a group of astronomers from Spain, the Netherlands, France, UK and USA have now reported their analysis of the phenomena. Their conclusions are inconclusive but they present two possible explanations.



Was dust lofted to extreme altitudes or ice crystals transported into space.? Hubble images show cloud formations (left) and the effects of a global dust storm on Mars (Credit: NASA/Hubbble)


Was dust lofted to extreme altitudes or ice crystals transported into space.? Hubble images show cloud formations (left) and the effects of a global dust storm on Mars (Credit: NASA/Hubbble)
Mars and mystery are synonymous. Among Martian mysteries, this one has persisted for three years. Our own planet, much more dynamic than Mars, continues to raise new questions and mysteries but Mars is a frozen desert. Frozen in time are features unchanged for billions of years.

An animated sequence of images taken by Wayne Jaeschke on March 20, 2012 showing the mystery plume over the western limb of the red planet (upper right). South is up in the photo. (Credit: W. Jaeschke)
In March 2012, the news of the observations caught the attention of Universe Today contributing writer Bob King. Reported on his March 22nd 2012 AstroBob blog page, the plumes or clouds were clear to see. The amateur observer, Wayne Jaeschke used his 14 inch telescope to capture still images which he stitched together into an animation to show the dynamics of the phenomena.

Now on February 16 of this year, a team of researchers led by Agustín Sánchez-Lavega of the University of the Basque Country in Bilbao, Spain, published their analysis in the journal Nature of the numerous observations, presenting two possible explanations. Their work is entitled: “An Extremely high-altitude plume seen at Mars morning terminator.”



Map from the Mars Global Surveyor of the current magnetic fields on Mars. Credit: NASA/JPL


Map from the Mars Global Surveyor of the current magnetic fields on Mars. Credit: NASA/JPL
The phenomena occurred over the Terra Cimmeria region centered at 45 degree south latitude. This area includes the tiger stripe array of magnetic fields emanating from concentrations of ferrous (iron) ore deposits on Mars; discovered by the Mars Global Surveyor magnetometer during low altitude aerobraking maneuvers at the beginning of the mission in 1998. Auroral events have been observed over this area from the interaction of the Martian magnetic field with streams of energetic particles streaming from the Sun. Sánchez-Lavega states that if these plumes are auroras, they would have to be over 1000 times brighter than those observed over the Earth.



Auroras photographed from The International Space Station. The distinct Manicouagan impact crater is seen in northern Canada. Terrestial aurora exist at altitudes of 100 km (60 miles) (Credit: NASA)


Auroras photographed from The International Space Station. The distinct Manicouagan impact crater is seen in northern Canada. Terrestial aurora exist at altitudes of 100 km (60 miles) (Credit: NASA)
The researchers also state that another problem with this scenario is the altitude. Auroras over Mars in this region have been observed up to 130 km, only half the height of the features. In the Earth’s field, aurora are confined to ionospheric altitudes – 100 km (60 miles). The Martian atmosphere at 200 km is exceedingly tenuous and the production of persistent and very bright aurora at such an altitude seems highly improbable.

The duration of the plumes – March 12th to 23rd, eleven days (after which observations of the area ended) and April 6th to 16th – is also a problem for this explanation. Auroral arcs on Earth are capable of persisting for hours. The Earth’s magnetic field functions like a capacitor storing charged particles from the Sun and some of these particles are discharged and produced the auroral oval and arcs. Over Mars, there is no equivalent capacitive storage of particles. Auroras over Mars are “WYSIWYG” – what you see is what you get – directly from the Sun. Concentrated solar high energy streams persisting for this long are unheard of.

The second explanation assessed by the astronomers is dust or ice crystals lofted to this high altitude. Again the altitude is the big issue. Martian dust storms will routinely lift dust to 60 km, still only one-third the height of the plumes. Martian dust devils will lift particles to 20 km. However, it is this second explanation involving ice crystals – Carbon Dioxide and Water – that the researchers give the most credence. In either instance, the particles must be concentrated and their reflectivity must account for the total brightness of the plumes. Ice crystals would be more easily transported to these heights, and also would be most highly reflective.

The paper also considered the shape of the plumes. The remarkable quality of modern amateur astrophotography cannot be overemphasized. Also the duration of the plumes was considered. By local noon and thereafter they were not observed. Again, the capabilities tendered by ground-based observations were unique and could not be duplicated by the present set of instruments orbiting Mars.



A Martian dust devil roughly 12 miles (20 kilometers) high was captured on Amazonis Planitia region of Mars, March 14, 2012 by the HiRISE camera on NASA's Mars Reconnaissance Orbiter. The plume is little more than three-quarters of a football field wide (70 yards, or 70 meters). (Image credit: NASA/JPL-Caltech/UA)


A Martian dust devil roughly 12 miles (20 kilometers) high was captured on Amazonis Planitia region of Mars, March 14, 2012 by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. The plume is little more than three-quarters of a football field wide (70 yards, or 70 meters). (Image credit: NASA/JPL-Caltech/UA)
Still too many questions remain and the researchers state that “both explanations defy our present understanding of the Mars’ upper atmosphere.” By March 20th and 21st, the researchers summarized that at least 18 amateur astronomers observed the plume using from 20 to 40 cm telescopes (8 to 16 inch diameter) at wavelengths from blue to red. At Mars, the Mars Color Imager on MRO (MARCI) could not detect the event due to the 2 hour periodic scans that are compiled to make global images.

Of the many ground observations, the researchers utilized two sets from the venerable astrophotographers Don Parker and Daiman Peach. While observations and measurements were limited, the researchers analysis was exhaustive and included modeling assuming CO2, Water and dust particles. The researchers did find a Hubble observation from 1997 that compared favorably with the 2012 events and likewise modeled that event for comparison. However, Hubble results provided a single observation and the height estimate could not be narrowly constrained.

Explanation of these events in 2012 are left open-ended by the research paper. Additional observations are clearly necessary. With increased interest from amateurs and continued quality improvements plus the addition of the Maven spacecraft suite of instruments plus India’s Mars Orbiter mission, observations will eventually be gained and a Martian mystery solved to make way for yet another.

References:

An Extremely High-Altitude Plume seen at Mars’ Morning Terminator, Journal Nature, February 16, 2015

Amateur astronomer photographs curious cloud on Mars, AstroBob, March 22, 2012



About 

Contributing writer Tim Reyes is a former NASA software engineer and analyst who has supported development of orbital and lander missions to the planet Mars since 1992. He has an M.S. in Space Plasma Physics from University of Alabama, Huntsville.

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Learn All About Pluto, The Most Famous Dwarf Planet

Learn All About Pluto, The Most Famous Dwarf Planet:



Artist's impression of New Horizons' encounter with Pluto and Charon. Credit: NASA/Thierry Lombry


Artist’s impression of New Horizons’ encounter with Pluto and Charon. Credit: NASA/Thierry Lombry
As the New Horizons spacecraft gathers information about Pluto before and after its July 2015 close encounter, practically every day we’re learning more about this dwarf planet.

Pluto is now becoming more to the public than just the planet that no longer was; before long, we’ll be able to understand much about its atmosphere, its moons and how it fits into the story of the Solar System’s history. Here are some of the most interesting things we know about Pluto so far.



1. Its definition of “dwarf planet” is controversial.

Back in 2006, the International Astronomical Union deemed Pluto is a dwarf planet and not a planet. The reasoning came after a few other objects were discovered far out in the Solar System that are close to Pluto’s size. That said, the principal investigator for New Horizons, Alan Stern, does not agree with the definition. At the time of the vote, he pointed out that the IAC’s definition of planet was not completely true of any larger body; for example, Earth does not clear the entire neighborhood of debris, which is one of the parts of the definition.

2. Pluto has several moons.

For decades, astronomers knew of Pluto and its moon, Charon. The two are so close in size that some people considered the system a double planet, but now that’s thrown in doubt with the dwarf planet designation. In any case, in the last decade humanity has discovered several more moons as telescope resolution and observing techniques improved. The other moons are called Nix, Hydra, Kerberos and Styx. For now we don’t know much about these smaller moons because it’s so difficult to resolve features on their tiny size.



HST Image of Pluto-Charon system. Also shown are Nix and Hydra. Image Credit: NASA/ESA


HST Image of Pluto-Charon system. Also shown are Nix and Hydra. Image Credit: NASA/ESA
3. Charon might have an ocean on it.

It seems unbelieveable that Charon could have an ocean given it’s so far away from the Sun, but at least one study suggests that it could be possible. Essentially, the tidal force imparted by Pluto’s gravity early in Charon’s history could have stretched the moon’s insides and warmed them up enough to create liquid. That said, it’s also possible that the ocean is now frozen as Charon’s orbit is not as eccentric as it was in the past.

4. Charon’s formation could have spawned the other moons.

As with our own Moon, some scientists believe Charon was created after a large object smashed into Pluto billions of years ago. This would have created a chain of debris circling the dwarf planet, which eventually coalesced into Charon. However, the other moons we know of near Pluto have almost exact resonances with Charon. This suggests that they also formed from the debris, one study says.



This "movie" of Pluto and its largest moon, Charon b yNASA's New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies - resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto's surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)


This “movie” of Pluto and its largest moon, Charon b yNASA’s New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies – resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
5. Pluto has an atmosphere.

Pluto is a tiny world, but like the Moon and Mercury it does have a very tenuous atmosphere that is called an “exosphere.” Astronomers first spotted signs of it in 1985. As Pluto passed in front of a star, they saw the star very slightly dim before Pluto completely blocked the star. The composition of this atmosphere is mostly made up of nitrogen and methane, and it freezes when Pluto is furthest from the Sun.

6. Pluto can get closer to the Sun than Neptune.

We used to think of Pluto as the furthest planet from the Sun, but in reality its orbit is so eccentric that it comes closer to the Sun than Neptune. According to NASA, its average distance from the Sun is 39.5 astronomical units (Earth-Sun distances), but it can come as close as 29.7 AU and as far away as 49.7 AU. It was last “inside” Neptune’s orbit between 1979 and 1999.



Pluto's surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Though the telescope is a powerful tool, the dwarf planet is so small that it is difficult to resolve its surface. Astronomers noted a bright spot (180 degrees) with an unusual abundance of carbon monoxide frost. Credit: NASA


Pluto’s surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Though the telescope is a powerful tool, the dwarf planet is so small that it is difficult to resolve its surface. Astronomers noted a bright spot (180 degrees) with an unusual abundance of carbon monoxide frost. Credit: NASA
7. Astronomers think Pluto looks a lot like Neptune’s moon, Triton.

Let’s be clear that Triton and Pluto have very different histories; for example, Triton was likely captured by Neptune long ago, an event that drastically altered its surface and its insides. But Pluto and Triton likely do have some similarities: the frozen volatiles (elements with low boiling points), the faint nitrogen atmospheres, and their similar composition of ice and rock. Scientists are pulling out old Voyager 2 pictures to make the comparisons as Pluto pictures arrive from New Horizons.

8. Pluto could have a ring system.

It’s not a guarantee, but at least one research team suggests that debris floating around Pluto could coalesce into a faint ring system. This wouldn’t be a large surprise, by the by, as we already know of at least one asteroid that has rings — so it is possible. Researchers on New Horizons will also be on the lookout for more moons and interesting features on Pluto’s surface such as cracks.



About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.

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Monday, February 16, 2015

Aurora and Volcanic Light Pillar

Aurora and Volcanic Light Pillar: APOD: 2014 September 23 - Aurora and Volcanic Light Pillar


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 September 23


See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.
Explanation: That's no sunset. And that thin red line just above it -- that's not a sun pillar. The red glow on the horizon originates from a volcanic eruption, and the red line is the eruption's reflection from fluttering atmospheric ice crystals. This unusual volcanic light pillar was captured over Iceland earlier this month. The featured scene looks north from Jökulsárlón toward the erupting volcano Bárðarbunga in the Holuhraun lava field. Even the foreground sky is picturesque, with textured grey clouds in the lower atmosphere, shimmering green aurora in the upper atmosphere, and bright stars far in the distance. Although the last eruption from Holuhraun was in 1797, the present volcanic activity continues.

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From the Temple of the Sun to the Temple of the Moon

From the Temple of the Sun to the Temple of the Moon: APOD: 2014 October 7 - From the Temple of the Sun to the Temple of the Moon


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 October 7


See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.
From the Temple of the Sun to the Temple of the Moon

Image Credit & Copyright: Dave Lane
Explanation: What connects the Sun to the Moon? Many answers have been given throughout history, but in the case of today's featured image, it appears to be the plane of our Milky Way Galaxy. The 16-image panorama was taken in Capitol Reef National Park, Utah, USA where two sandstone monoliths -- the Temple of the Moon on the right and the Temple of the Sun on the left -- rise dramatically from the desert. Each natural monument stands about 100 meters tall and survives from the Jurassic period 160 million years ago. Even older are many of the stars and nebulas that dot the celestial background, including the Andromeda Galaxy. Tomorrow the Earth will connect the Sun to the Moon by way of its shadow: a total lunar eclipse will be visible from many locations around the globe.

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NGC 6823: Cloud Sculpting Star Cluster

NGC 6823: Cloud Sculpting Star Cluster: APOD: 2014 October 8 - NGC 6823: Cloud Sculpting Star Cluster


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2014 October 8


See Explanation. Clicking on the picture will download the highest resolution version available.
Explanation: Star cluster NGC 6823 is slowly turning gas clouds into stars. The center of the open cluster, visible on the upper right, formed only about two million years ago and is dominated in brightness by a host of bright young blue stars. Some outer parts of the cluster, visible in the featured image's center as the stars and pillars of emission nebula NGC 6820, contain even younger stars. The huge pillars of gas and dust likely get their elongated shape by erosion from hot radiation emitted from the brightest cluster stars. Striking dark globules of gas and dust are also visible across the upper left of the featured image. Open star cluster NGC 6823 spans about 50 light years and lies about 6000 light years away toward the constellation of the Fox (Vulpecula).

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Eclipse at Moonset

Eclipse at Moonset: APOD: 2014 October 9 - Eclipse at Moonset


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2014 October 9


See Explanation. Clicking on the picture will download the highest resolution version available.
Explanation: The Pacific Ocean and Chilean coast lie below this sea of clouds. Seen through the subtle colors of the predawn sky a lunar eclipse is in progress above, the partially eclipsed Moon growing dark. The curved edge of planet Earth's shadow still cuts across the middle of the lunar disk as the Moon sinks lower toward the western horizon. In fact, from this southern hemisphere location as well as much of eastern North America totality, the Moon completely immersed within Earth's shadow, began near the time of moonset and sunrise on October 8. From farther west the total phase could be followed for almost an hour though, the darker reddened Moon still high in the night sky.

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Moons at Opposition

Moons at Opposition: APOD: 2014 October 10 - Moons at Opposition


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2014 October 10


See Explanation. Moving the cursor over the image will bring up an alternate version. Clicking on the image will bring up the highest resolution version available.
Explanation: From the early hours of October 8, over the Santa Cruz Mountains near Los Gatos, California, the totally eclipsed Moon shows a range of color across this well-exposed telescopic view of the lunar eclipse. Of course, a lunar eclipse can only occur when the Moon is opposite the Sun in Earth's sky and gliding through the planet's shadow. But also near opposition during this eclipse, and remarkably only half a degree or so from the lunar limb, distant Uranus is faint but easy to spot at the lower right. Fainter still are the ice giant's moons. To find them, slide your cursor over the image (or just follow this link) to check out a longer exposure. While even the darkened surface of our eclipsed Moon will be strongly overexposed, Uranus moons Titania, Oberon, and Umbriel can just be distinguished as faint pinpricks of light.

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Eclipse at Moonrise

Eclipse at Moonrise: APOD: 2014 October 11 - Eclipse at Moonrise


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2014 October 11


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Explanation: As the Moon rose and the Sun set on October 8, a lunar eclipse was in progress seen from Chongqing, China. Trailing through this composite time exposure, the rising Moon began as a dark reddened disk in total eclipse near the eastern horizon. Steadily climbing above the populous city's colorful lights along the Yangtze River, the moontrail grows brighter and broader, until a bright Full Moon emerged from the Earth's shadow in evening skies. Although lunar eclipses are not always total ones, this eclipse, along with last April's lunar eclipse, were the first two of four consecutive total lunar eclipses, a series known as a tetrad. The final two eclipses of this tetrad will occur in early April and late September 2015.

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The Helix Nebula from Blanco and Hubble

The Helix Nebula from Blanco and Hubble: APOD: 2014 October 12 - The Helix Nebula from Blanco and Hubble





Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2014 October 12




See Explanation. Clicking on the picture will download the highest resolution version available.
The Helix Nebula from Blanco and Hubble
Image Credit:
C. R. O'Dell,
(Vanderbilt) et al.
ESA,
NOAO,
NASA
Explanation:
How did a star create the
Helix nebula?

The shapes of
planetary nebula like the
Helix are important because they
likely hold clues to how stars like the
Sun end their lives.

Observations by the orbiting
Hubble Space Telescope and the
4-meter Blanco Telescope in
Chile, however, have shown the
Helix is not really a
simple helix.

Rather, it incorporates two nearly perpendicular disks as well as arcs, shocks, and even
features not well understood.

Even so, many strikingly geometric symmetries remain.

How a single Sun-like star created such beautiful yet
geometric complexity is a topic of research.

The Helix Nebula is the nearest
planetary nebula to Earth, lies only about 700
light years away toward the constellation of Aquarius, and spans about 3 light-years.






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Nebulas and Star Clusters
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Auroral Corona over Norway

Auroral Corona over Norway: APOD: 2014 October 14 - Auroral Corona over Norway


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 October 14


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Explanation: Higher than the highest mountain lies the realm of the aurora. Auroras rarely reach below 60 kilometers, and can range up to 1000 kilometers. Aurora light results from energetic electrons and protons striking atoms and molecules in the Earth's atmosphere. Somewhat uncommon, an auroral corona appears as a center point for a surrounding display and may occur when an aurora develops directly overhead, or when auroral rays are pointed nearly toward the observer. This picturesque but brief green and purple aurora exhibition occurred last month high above Kvaløya, Tromsø, Norway. The Sessøyfjorden fjord runs through the foreground, while numerous stars are visible far in the distance.

Posted by Nelio Inacio at 5:46 AM 0 comments
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Messier 6 and Comet Siding Spring

Messier 6 and Comet Siding Spring: APOD: 2014 October 17 - Messier 6 and Comet Siding Spring


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2014 October 17


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Explanation: This looks like a near miss but the greenish coma and tail of Comet Siding Spring (C/2013 A1) are really 2,000 light-years or so away from the stars of open cluster Messier 6. They do appear close together though, along the same line-of-sight in this gorgeous October 9th skyscape toward the constellation Scorpius. Still, on Sunday, October 19th this comet really will be involved in a near miss, passing within only 139,500 kilometers of planet Mars. That's about 10 times closer than any known comet flyby of planet Earth, and nearly one third the Earth-Moon distance. While an impact with the nucleus is not a threat the comet's dust, moving with a speed of about 56 kilometers per second relative to the Red Planet, and outskirts of its gaseous coma could interact with the thin Martian atmosphere. Of course, the comet's close encounter will be followed intently by spacecraft in Martian orbit and rovers on the surface.

Posted by Nelio Inacio at 5:45 AM 0 comments
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Melotte 15 in the Heart

Melotte 15 in the Heart: APOD: 2014 October 18 - Melotte 15 in the Heart


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2014 October 18


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Explanation: Cosmic clouds form fantastic shapes in the central regions of emission nebula IC 1805. The clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are toward the right in this colorful skyscape, along with dark dust clouds in silhouette against glowing atomic gas. A composite of narrowband and broadband telescopic images, the view spans about 30 light-years and includes emission from ionized hydrogen, sulfur, and oxygen atoms mapped to green, red, and blue hues in the popular Hubble Palette. Wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - The Heart Nebula. IC 1805 is located about 7,500 light years away toward the boastful constellation Cassiopeia.

Posted by Nelio Inacio at 5:44 AM 0 comments
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Comet Siding Spring Passes Mars

Comet Siding Spring Passes Mars: APOD: 2014 October 20 - Comet Siding Spring Passes Mars


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2014 October 20


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Explanation: Yesterday, a comet passed very close to Mars. In fact, Comet C/2013 A1 (Siding Spring) passed closer to the red planet than any comet has ever passed to Earth in recorded history. To take advantage of this unique opportunity to study the close interaction of a comet and a planet, humanity currently has five active spacecraft orbiting Mars: NASA's MAVEN, MRO, Mars Odyssey, as well as ESA's Mars Express, and India's Mars Orbiter. Most of these spacecraft have now sent back information that they have not been damaged by small pieces of the passing comet. These spacecraft, as well as the two active rovers on the Martian surface -- NASA's Opportunity and Curiosity -- have taken data and images that will be downloaded to Earth for weeks to come and likely studied for years to come. The featured image taken yesterday, however, was not taken from Mars but from Earth and shows Comet Siding Spring on the lower left as it passed Mars, on the upper right.

Posted by Nelio Inacio at 5:42 AM 0 comments
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Mimas: Small Moon with a Big Crater

Mimas: Small Moon with a Big Crater: APOD: 2014 October 21 - Mimas: Small Moon with a Big Crater


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2014 October 21


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Explanation: Whatever hit Mimas nearly destroyed it. What remains is one of the largest impact craters on one of Saturn's smallest moons. The crater, named Herschel after the 1789 discoverer of Mimas, Sir William Herschel, spans about 130 kilometers and is pictured above. Mimas' low mass produces a surface gravity just strong enough to create a spherical body but weak enough to allow such relatively large surface features. Mimas is made of mostly water ice with a smattering of rock - so it is accurately described as a big dirty snowball. The above image was taken during the 2010 February flyby of the robot spacecraft Cassini now in orbit around Saturn. A recent analysis of Mimas's unusual wobble indicates that it might house a liquid water interior ocean.

Posted by Nelio Inacio at 5:41 AM 0 comments
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Galaxies in Pegasus

Galaxies in Pegasus: APOD: 2014 October 23 - Galaxies in Pegasus


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 October 23
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Explanation: This wide, sharp telescopic view reveals galaxies scattered beyond the stars and faint dust nebulae of the Milky Way at the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan's Quintet. About 300 million light-years distant, the quintet dramatically illustrates a multiple galaxy collision, its powerful, ongoing interactions posed for a brief cosmic snapshot. On the sky, the quintet and NGC 7331 are separated by about half a degree.

Posted by Nelio Inacio at 5:40 AM 0 comments
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