2017 November 17

**panosol** Παρ Νοε 17, 2017 7:54 pm

2017 November 17
Astronomy Picture of the Day - Σελίδα 14 Meteor2017event4299_Taylor

Major Fireball Meteor
Image Credit & Copyright: Ollie Taylor

Explanation: The sky glows with soft pinkish colors of fading twilight in this serendipitous mountaintop vista. Taken in subfreezing temperatures, the thoughtfully composed photo shows snowy, rugged peaks seen from a mountain pass on November 14. Below lies the village of La Villa, Alta Badia in Italy's Dolomite Alps. Above the nestled village lights, the constellation Ursa Major hangs over the northern horizon. But most stunning is the intense fireball meteor. It was captured during the camera's exposure by chance as it flashed east to west across the northern horizon, under Ursa Major's familiar Big Dipper asterism. In fact, sightings of this major fireball meteor were widely reported in European skies, the most reported fireball event ever for planet Earth's American Meteor Society and the International Meteor Organization. The meteor's measured track over Germany is consistent with its origin near the active radiant of November's Taurid Meteor Shower. Taurid meteors are associated with dust from Encke's comet.

**panosol** Σαβ Νοε 18, 2017 10:59 am

2017 November 18
Astronomy Picture of the Day - Σελίδα 14 20171117dawn_Tezel

Friday, the Moon Smiled
Image Credit & Copyright: Tunç Tezel (TWAN)

Explanation: Friday, an old Moon smiled for early morning risers. Its waning sunlit crescent is captured in this atmospheric scene from clear skies near Bursa, Turkey, planet Earth. In the subtle twilight hues nearby celestial lights are Jupiter (top) and Venus shining close to the eastern horizon. But today, Saturday, the Moon will be new and early next week its waxing crescent will follow the setting Sun as it sinks in the west. Then, a young Moon's smile will join Saturn and Mercury in early evening skies.

**panosol** Κυρ Νοε 19, 2017 11:28 am

2017 November 19
Astronomy Picture of the Day - Σελίδα 14 Ngc7822_WISEantonucci_1824c

NGC 7822: Stars and Dust Pillars in Infrared
Image Credit: WISE, IRSA, NASA; Processing & Copyright : Francesco Antonucci

Explanation: Young stars themselves are clearing out their nursery in NGC 7822. Within the nebula, bright edges and complex dust sculptures dominate this detailed skyscape taken in infrared light by NASA's Wide Field Infrared Survey Explorer (WISE) satellite. NGC 7822 lies at the edge of a giant molecular cloud toward the northern constellation Cepheus, a glowing star forming region that lies about 3,000 light-years away. The atomic emission of light by the nebula's gas is powered by energetic radiation from the hot stars, whose powerful winds and light also sculpt and erode the denser pillar shapes. Stars could still be forming inside the pillars by gravitational collapse, but as the pillars are eroded away, any forming stars will ultimately be cut off from their reservoir of star stuff. This field spans around 40 light-years at the estimated distance of NGC 7822.

**panosol** Δευ Νοε 20, 2017 6:45 pm

2017 November 20
Astronomy Picture of the Day - Σελίδα 14 Selfie_Curiosity_3577

Curiosity Rover Takes Selfie on Mars
Image Credit: NASA, JPL-Caltech, MSSS

Explanation: Yes, but have you ever taken a selfie on Mars? The Curiosity rover on Mars has. This selfie was compiled from many smaller images -- which is why the mechanical arm holding the camera is not visible. (Although its shadow is!) Taken in mid-2015, the featured image shows not only the adventurous rover, but dark layered rocks, the light colored peak of Mount Sharp, and the rusting red sand that pervades Mars. If you look closely, you can even see that a small rock is stuck into one of Curiosity's aging wheels. Now nearing the end of 2017, Curiosity continues to explore the layers of sedimentary rocks it has discovered on Vera Rubin Ridge in order to better understand, generally, the ancient geologic history of Mars and, specifically, why these types of rocks exist there.

**panosol** Τρι Νοε 21, 2017 7:52 pm

2017 November 21
Astronomy Picture of the Day - Σελίδα 14 Big_Dipper_Mt2_Cullen_1365

Big Dipper over Pyramid Mountain
Image Credit & Copyright: Steve Cullen

Explanation: When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known in the USA as the Big Dipper, the stars are part of a constellation designated by the International Astronomical Union in 1922 as the Great Bear (Ursa Major). The recognized star names of these stars are (left to right) Alkaid, Mizar/Alcor, Alioth, Megrez, Phecda, Merak, and Dubhe. Of course, stars in any given constellation are unlikely to be physically related. But surprisingly, most of the Big Dipper stars do seem to be headed in the same direction as they plough through space, a property they share with other stars spread out over an even larger area across the sky. Their measured common motion suggests that they all belong to a loose, nearby star cluster, thought to be on average only about 75 light-years away and up to 30 light-years across. The cluster is more properly known as the Ursa Major Moving Group. The featured image captured the iconic stars recently above Pyramid Mountain in Alberta, Canada.

**panosol** Τετ Νοε 22, 2017 6:45 pm

2017 November 22
Astronomy Picture of the Day - Σελίδα 14 Oumuamua_Drawing_ESO_1280

'Oumuamua: Interstellar Asteroid
Illustration Credit: European Southern Observatory, M. Kornmesser

Explanation: Nothing like it has ever been seen before. The unusual space rock 'Oumuamua is so intriguing mainly because it is the first asteroid ever detected from outside our Solar System -- although likely many more are to follow given modern computer-driven sky monitoring. Therefore humanity's telescopes -- of nearly every variety -- have put 'Oumuamua into their observing schedule to help better understand this unusual interstellar visitor. Pictured is an artist's illustration of what 'Oumuamua might look like up close. 'Oumuamua is also intriguing, however, because it has unexpected parallels to Rama, a famous fictional interstellar spaceship created by the late science fiction writer Arthur C. Clarke. Like Rama, 'Oumuamua is unusually elongated, should be made of strong material to avoid breaking apart, is only passing through our Solar System, and passed unusually close to the Sun for something gravitationally unbound. Unlike a visiting spaceship, though, 'Oumuamua's trajectory, speed, color, and even probability of detection are consistent with it forming naturally around a normal star many millions of years ago, being expelled after gravitationally encountering a normal planet, and subsequently orbiting in our Galaxy alone. Even given 'Oumuamua's likely conventional origin, perhaps humanity can hold hope that one day we will have the technology to engineer 'Oumuamua -- or another Solar System interloper -- into an interstellar Rama of our own.

**panosol** Πεμ Νοε 23, 2017 6:31 pm

2017 November 23
Astronomy Picture of the Day - Σελίδα 14 Belt_Stars_nouroozi2000

Alnitak, Alnilam, Mintaka
Image Credit & Copyright: Mohammad Nouroozi

Explanation: Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (lower right to upper left) along the diagonal in this cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie from 800 to 1,500 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the lower right. The famous Orion Nebula itself is off the right edge of this colorful starfield. This well-framed, 2-panel telescopic mosaic spans about 4 degrees on the sky.

**panosol** Παρ Νοε 24, 2017 8:57 pm

2017 November 24
Astronomy Picture of the Day - Σελίδα 14 Moonshorty_apollo17_1498

Apollo 17 at Shorty Crater
Image Credit: Apollo 17 Crew, NASA

Explanation: In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon in the Taurus-Littrow valley, while colleague Ronald Evans orbited overhead. This sharp image was taken by Cernan as he and Schmitt roamed the valley floor. The image shows Schmitt on the left with the lunar rover at the edge of Shorty Crater, near the spot where geologist Schmitt discovered orange lunar soil. The Apollo 17 crew returned with 110 kilograms of rock and soil samples, more than was returned from any of the other lunar landing sites. Forty five years later, Cernan and Schmitt are still the last to walk on the Moon.

**panosol** Σαβ Νοε 25, 2017 9:50 am

2017 November 25
Astronomy Picture of the Day - Σελίδα 14 Horizon2horizon_JFGraffand

Crossing Horizons
Image Credit & Copyright: Jean-Francois Graffand

Explanation: Follow this vertical panoramic view from horizon to horizon and your gaze will sweep through the zenith of a dark night sky over Pic du Midi mountaintop observatory. To make the journey above a sea of clouds, 19 single exposures were taken near the end of night on October 31 and assembled in a mercator projection that renders the two horizons flat. Begin at the top and you're looking east toward the upsidedown dome of the observatory's 1 meter telescope. It's easy to follow the plane of our Milky Way galaxy as it appears to emerge from the dome and angle down toward the far horizon. Just to its right, the sky holds a remarkable diffuse glow of zodiacal light along our Solar System's ecliptic plane. Zodiacal light and Milky Way with star clusters, cosmic dust clouds and faint nebulae, cross near the zenith. Both continue down toward the airglow in the west. They disappear near the western horizon at the bottom, beyond more Pic du Midi observatory domes and a tall communications relay antenna.

**panosol** Κυρ Νοε 26, 2017 11:09 am

2017 November 26

Our Story in One Minute
Video Credit & Copyright: MelodySheep, Symphony of Science, John Boswell; Music Credit: Our Story

Explanation: Do you have a minute -- to see the entire backstory of human existence? This thrilling video culls together multiple teasing video snippets in an attempt to succinctly summarize our history. And sets it to music. Briefly depicted, from start to finish, is an artistic animation of the Big Bang, a trip across the early universe, the formation of the Earth and Moon, the emergence of multi-celled life and plants, the rise of reptiles and dinosaurs, a devastating meteor strike, the rise of mammals and humans, and finally the rise of modern civilization. The minute movie ends with a flyover of the modern skyscraper and a human standing atop a snow covered mountain.

**panosol** Δευ Νοε 27, 2017 6:44 pm

2017 November 27

Hurricane Season Animated
Video Credit: M. R. Radcliff (USRA) et al., NASA's GSFC, SVS; Music: Elapsing Time by C. Telford & R. A. Navarro (ASCAP)

Explanation: Where do hurricanes go? To better understand dangerous storms, NASA compiled data from several satellites into a supercomputer simulation of this past year's hurricane season. Specifically, the featured video shows how smoke (white), sea salt (blue), and dust (brown) tracked from 2017 August through October across the northern half of Earth's Western Hemisphere. These aerosols usefully trace sometimes invisible winds. In the midst of the many mesmerizing flows, hurricanes can be seen swirling across the Atlantic Ocean on the right. Some of these hurricanes lashed islands and coastal regions in North America before dissipating in the northern Atlantic. Studying this year's weather patterns may bolster more accurate storm forecasts as soon as next year.

**panosol** Τρι Νοε 28, 2017 6:59 pm

2017 November 28
Astronomy Picture of the Day - Σελίδα 14 Spiral_Cloud_Juno_4512

Juno Spots a Complex Storm on Jupiter
Image Credit: NASA, JPL-Caltech, SwRI, MSSS; Processing: Gerald Eichstädt & Seán Doran

Explanation: Some storms on Jupiter are quite complex. The swirling storm was captured late last month by the NASA's robotic Juno spacecraft currently orbiting the Solar System's largest planet. The featured image spans about 30,000 kilometers, making this storm system just about as wide as planet Earth. The disturbance rotates counter-clockwise and shows a cloud pattern that includes light-colored updrafts thought to be composed predominantly of ammonia ice. These light clouds are the highest up and even cast discernable shadows toward the right. Juno will continue to orbit and probe Jupiter over the next few years as it tries to return data that help us to better understand Jupiter's atmospheric water abundance and if the planet has a solid surface underneath these fascinating clouds.

**panosol** Τετ Νοε 29, 2017 6:33 pm

2017 November 29
Astronomy Picture of the Day - Σελίδα 14 Orion_Dust_Battistella_1824

M42: The Great Orion Nebula
Image Credit & Copyright: Francesco Battistella

Explanation: Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud. Many of the filamentary structures visible in the featured image are actually shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same spiral arm of our Galaxy as the Sun. The Great Nebula in Orion can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. The featured image, taken last month, shows a two-hour exposure of the nebula in three colors. The whole Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.

**panosol** Πεμ Νοε 30, 2017 6:26 pm

2017 November 30
Astronomy Picture of the Day - Σελίδα 14 M33_Nagy_tamed

M33: Triangulum Galaxy
Image Credit & Copyright: Peter Nagy

Explanation: The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this sharp composite image nicely shows off M33's blue star clusters and pinkish star forming regions along the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 7 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.

**panosol** Παρ Δεκ 01, 2017 7:24 pm

2017 December 1
Astronomy Picture of the Day - Σελίδα 14 NGC7000_Paolo_Moroni

North America and the Pelican
Image Credit & Copyright: Paolo Moroni

Explanation: Fans of our fair planet might recognize the outlines of these cosmic clouds. On the left, bright emission outlined by dark, obscuring dust lanes seems to trace a continental shape, lending the popular name North America Nebula to the emission region cataloged as NGC 7000. To the right, just off the North America Nebula's east coast, is IC 5070, whose profile suggests the Pelican Nebula. The two bright nebulae are about 1,500 light-years away, part of the same large and complex star forming region, almost as nearby as the better-known Orion Nebula. At that distance, the 6 degree wide field of view would span 150 light-years. This careful cosmic portrait uses narrow band images to highlight the bright ionization fronts and the characteristic red glow from atomic hydrogen gas. These nebulae can be seen with binoculars from a dark location. Look northeast of bright star Deneb in the constellation of Cygnus the Swan.

**panosol** Σαβ Δεκ 02, 2017 8:49 am

2017 December 2
Astronomy Picture of the Day - Σελίδα 14 Messier_Crater3d_vantuyne

Messier Craters in Stereo
Image Credit: Apollo 11, NASA; Stereo Image Copyright Patrick Vantuyne

Explanation: Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier, from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon. Standouts in the dark, smooth lunar Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their elongated shapes are explained by a left-to-right moving, extremely shallow-angle trajectory followed by an impactor that gouged out the craters. The shallow impact also resulted in two bright rays of material extending along the surface to the right, beyond the picture. Intended to be viewed with red/blue glasses (red for the left eye), this striking stereo picture of the crater pair was recently created from high resolution scans of two images (AS11-42-6304, AS11-42-6305) taken during the Apollo 11 mission to the moon.

**panosol** Κυρ Δεκ 03, 2017 10:01 am

2017 December 3

Astronomy Picture of the Day - Σελίδα 14 Screenshot-2017-12-3_Astronomy_Picture_of_the_Da

click image to watch on vimeo

Full Moon Silhouettes
Video Credit & Copyright: Mark Gee; Music: Tenderness (Dan Phillipson)

Explanation: Have you ever watched the Moon rise? The slow rise of a nearly full moon over a clear horizon can be an impressive sight. One impressive moonrise was imaged in early 2013 over Mount Victoria Lookout in Wellington, New Zealand. With detailed planning, an industrious astrophotographer placed a camera about two kilometers away and pointed it across the lookout to where the Moon would surely soon be making its nightly debut. The featured single shot sequence is unedited and shown in real time -- it is not a time lapse. People on Mount Victoria Lookout can be seen in silhouette themselves admiring the dawn of Earth's largest satellite. Seeing a moonrise yourself is not difficult: it happens every day, although only half the time at night. Each day the Moon rises about fifty minutes later than the previous day, with a full moon always rising at sunset. A good time to see a full moonrise will occur tonight at sunset as the Moon's relative closeness to Earth during a full phase -- called a supermoon -- will cause it to appear slightly larger and brighter than usual.

**panosol** Δευ Δεκ 04, 2017 7:01 pm

2017 December 4

Earth and Moon
Images Credit: NASA, JPL, Galileo Project; Processing & License: Gordan Ugarkovic

Explanation: On rare occasions, the Earth and Moon are photographed together. One of most spectacular times this occurred was 25 years ago this month when the Jupiter-bound Galileo spacecraft zoomed past our home planetary system. Then, robotic Galileo watched from about 15-times the Earth-Moon separation as our only natural satellite glided past our home world. The featured video combines 52 historic color-enhanced images. Although our Moon may appear small next to the Earth, no other planet in our Solar System has a satellite so comparable in size . The Sun, far off to the right, illuminated about half of each sphere, and shows the spinning Earth's white clouds, blue oceans, and tan continents. Tonight, a nearly full Oak supermoon will be visible from all of Earth from sunset to sunrise.

**panosol** Τρι Δεκ 05, 2017 7:11 pm

2017 December 5
Astronomy Picture of the Day - Σελίδα 14 Blue_Moon_Red_Volcano_Montufar_4096

A Horizon with Blue and Red
Image Credit & Copyright: Sergio Montúfar (Planetario Ciudad de La Plata)

Explanation: What's happening on the horizon? The horizon itself, past a spinach field in Guatemala, shows not only trees but a large volcano: the Volcán de Fuego (Volcano of Fire). The red glow at the top of the volcano is hot lava. But your eye may also be drawn to the blue circle above the horizon on the left. This circle surrounds the Moon and, together with other colors, is called a corona. A corona is caused by diffraction of light -- here moonlight -- by small water droplets in the Earth's intervening atmosphere. A break in the clouds on the right shows stars and even the planet Saturn far beyond the volcano. Although Volcán de Fuego frequently undergoes low-level activity, the astrophotographer considered himself lucky to capture the scene just during an explosive eruption in late September.

**panosol** Τετ Δεκ 06, 2017 7:03 pm

2017 December 6
Astronomy Picture of the Day - Σελίδα 14 HH666_Hubble_Pestana_2495

HH 666: Carina Dust Pillar with Jet
Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Domingo Pestana

Explanation: To some, it may look like a beehive harboring an evil bee. In reality, the featured Hubble image captures a cosmic pillar of dust, two-light years long, inside of which is Herbig-Haro 666 -- a young star emitting powerful jets. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's layered outline are shaped by the winds and radiation of Carina's young, hot, massive stars, some of which are still forming inside the nebula. A dust-penetrating view in infrared light better shows the two, narrow, energetic jets blasting outward from a still hidden infant star.

**panosol** Πεμ Δεκ 07, 2017 6:41 pm

2017 December 7
Astronomy Picture of the Day - Σελίδα 14 2017_All_Eclipses_1800px

All the Eclipses of 2017
Image Credit & Copyright: Petr Horálek

Explanation: As seen from planet Earth, all the lunar and solar eclipses of 2017 are represented at the same scale in these four panels. The year's celestial shadow play was followed through four different countries by one adventurous eclipse chaser. To kick off the eclipse season, at top left February's Full Moon was captured from the Czech Republic. Its subtle shading, a penumbral lunar eclipse, is due to Earth's lighter outer shadow. Later that month the New Moon at top right was surrounded by a ring of fire, recorded on film from Argentina near the midpoint of striking annular solar eclipse. The August eclipse pairing below finds the Earth's dark umbral shadow in a partial eclipse from Germany at left, and the vibrant solar corona surrounding a totally eclipsed Sun from the western USA. If you're keeping score, the Saros numbers (eclipse cycles) for all the 2017 eclipses are at bottom left in each panel.

**panosol** Παρ Δεκ 08, 2017 8:56 pm

2017 December 8
Astronomy Picture of the Day - Σελίδα 14 2017_Super_Moon_Alps_Superga

Alpine Superga Moonset
Image Credit & Copyright: Stefano De Rosa

Explanation: December's Full Moon phase occurred near perigee, the closest point in its orbit around our fair planet. Big and bright, the fully illuminated lunar disk sets over rugged mountains in this early morningscape from Turin, Italy. Captured just before sunrise on the opposite horizon, scattered sunlight near the edge of Earth's shadow provides the beautiful reddish glow of the alpine peaks. Hills in the foreground are still in shadow. But the scattered sunlight just illuminates the dome and towers of Turin's historic Basilica of Superga on a hilltop near the lower right in the telephoto frame.

**panosol** Σαβ Δεκ 09, 2017 9:29 am

2017 December 9
Astronomy Picture of the Day - Σελίδα 14 RBA_DS_Clouds_of_Aries

Stardust in Aries
Image Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)

Explanation: This composition in stardust covers over 8 degrees on the northern sky. The mosaicked field of view is west of the familiar Pleiades star cluster, toward the zodiacal constellation Aries and the plane of our Milky Way Galaxy. At right in the deep skyscape is bluish Epsilon Arietis, a star visible to the naked-eye and about 330 light-years away. Reflecting starlight in the region, dusty nebulae LBN762, LBN753, and LBN743 sprawl left to right across the field, but are likely some 1,000 light-years away. At that estimated distance, the cosmic canvas is over 140 light-years across. Near the edge of a large molecular cloud, their dark interiors can hide newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form around dense cores embedded in the molecular cloud.

**panosol** Κυρ Δεκ 10, 2017 9:05 am

2017 December 10
Astronomy Picture of the Day - Σελίδα 14 Greencompany_rive_2916

In Green Company: Aurora over Norway
Image Credit & Copyright: Max Rive

Explanation: Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display. Arms went high in the air, patience and experience paid off, and the creative featured image was captured as a composite from three separate exposures. The setting is a summit of the Austnesfjorden fjord close to the town of Svolvear on the Lofoten islands in northern Norway. The time was early 2014. Although our Sun is nearing Solar Minimum and hence showing relatively little surface activity, holes in the upper corona have provided some nice auroral displays over the last few months.

**panosol** Δευ Δεκ 11, 2017 7:27 pm

2017 December 11

Mercury Visualized from MESSENGER
Video Credit: NASA, JHUAPL, CIW; Processing: Roman Tkachenko; Music: Open Sea Morning by Puddle of Infinity

Explanation: What would it be like to fly over the planet Mercury? Images and data taken from NASA's robotic MESSENGER spacecraft that orbited Mercury from 2011 to 2015 have been digitally combined to envision a virtual flight that highlights much of the hot planet's surface. In general, the Solar System's innermost world appears similar to Earth's Moon as it is covered by a heavily cratered gray terrain. MESSENGER discovered much about Mercury including that shadows near its poles likely host water ice. The featured video opens as Mercury is viewed from the Sun-facing side and concludes with the virtual spacecraft retreating into Mercury's night. Mercury actually rotates so slowly that it only completes three rotations for every two trips around the Sun. In 2018, Europe and Japan plan to launch BepiColombo to better map Mercury's surface and probe its magnetic field.