Dalla stazione spaziale: il pianeta di Yuri, illuminato...

Il Pianeta di Yuri

Immagine di: ISS Expedition 30, la NASA (APOD)

In un altro 12 aprile, nel 1961, il cosmonauta sovietico Yuri Gagarin Alexseyevich divenne il primo essere umano a vedere il pianeta Terra dallo spazio. Commentando la sua visuale dall'orbita riferiva:" Il cielo è molto scuro, la Terra è bluastra Tutto si scorge in modo molto chiaro."
In un altro 12 aprile, nel 1981, la NASA ha lanciato il primo Space Shuttle.

Nel 2013 questa immagine dalla Stazione spaziale internazionale orbitante fornisce una vista mozzafiato del pianeta di notte da orbita terrestre bassa. Costellazioni di luci che collegano le città densamente popolate lungo la costa atlantica orientale degli Stati Uniti sono incorniciate da due veicoli spaziali russi ancorati alla stazione spaziale.
Facile da riconoscere le città : New York e Long Island a destra. Da lì, a seguire verso sinistra, Filadelfia, Baltimora, Washington DC vicino al centro dell'immagine.

La cometa PanStarrs e la Galassia di Andromeda... dalla Russia

Da APOD

Comet PANSTARRS and the Andromeda Galaxy

Image Credit & Copyright: Pavel Smilyk

Explanation: Currently, comet PANSTARRS is passing nearly in front of the galaxy Andromeda. Coincidentally, both comet and galaxy appear now to be just about the same angular size. In physical size, even though Comet PANSTARRS is currently the largest object in the Solar System with a tail spanning about 15 times the diameter of the Sun, it is still about 70 billion times smaller than the Andromeda galaxy (M31). The above image was captured on March 30, near Syktyvkar, Russia. As C/2011 L4 (PANSTARRS) on the lower left recedes from the Sun and dims, it is returning to the northerly direction whence it came. When the comet will return is currently unknown, although humans may have merged with computers by then

Lo strano arcobaleno di Parigi...

La settimana scorsa uno strano fenomeno, durato pochi minuti, ha colpito i parigini. Un orizzonte colorato come un arcobaleno nel pieno di una giornata di pioggia, con nuvole. E, la fascia colorata dietro la Tour Eiffel, era proprio un arcobaleno, disposto lungo l'orizzonte, perché contrariamente a quanto di solito succede in quel momento il Sole era molto alto e l'arcobaleno, che si forma sulla parte opposta a quella del Sole, copriva appunto l'orizzonte. Insomma, i parigini vedevano soltanto i culmine dell'arcobaleno... La parte restante era sotto l'orizzonte.

Astronomy Picture of the Day

A Horizon Rainbow in Paris

Image Credit & Copyright: Bertrand Kulik

Spettacolo: le due comete di marzo nel cielo americano...

Comets Lemmon and PanSTARRS Peaking

Image Credit & Copyright: Yuri Beletsky (ESO)

Explanation: Two impressive comets will both reach their peak brightness during the next two weeks. Taking advantage of a rare imaging opportunity, both of these comets were captured in the sky together last week over the Atacama desert in South America. Comet C/2012 F6 (Lemmon), visible on the upper left of the above image, is sporting a long tail dominated by glowing green ions. Comet C/2011 L4 (PanSTARRS), visible near the horizon on the lower right, is showing a bright tail dominated by dust reflecting sunlight. The tails of both comets point approximately toward the recently set Sun. Comet Lemmon will be just barely visible to the unaided eye before sunset in southern skies for the next week, and then best viewed with binoculars as it fades and moves slowly north. Comet PanSTARRS, however, will remain visible in southern skies for only a few more days, after which it will remain bright enough to be locatable with the unaided eye as it moves into northern skies. To find the giant melting snowball PanSTARRS, sky enthusiasts should look toward the western horizon just after sunset. Deep sky observers are also monitoring the brightening of Comet C/2012 S1 (ISON), which may become one of the brightest objects in the entire night sky toward the end of 2013.

La Luna, GIove e l'aereo ...

Fly Me to the Moons

Image Credit & Copyright: Greg Gibbs (Capturing the Night

Explanation: Sometimes the Moon is a busy direction. Last week, for example, our very Moon passed in front of the planet Jupiter. While capturing this unusual spectacle from New South Wales, Australia, a quick-thinking astrophotographer realized that a nearby plane might itself pass in front of the Moon, and so quickly reset his camera to take a continuous series of short duration shots. As hoped, for a brief instant, that airplane, the Moon, and Jupiter were all visible in a single exposure, which is shown above. But the project was not complete -- a longer exposure was then taken to bring up three of the Jupiter's own moons: Io, Calisto, and Europa (from left to right). Unfortunately, this triple spectacle soon disappeared. Less than a second later, the plane flew away from the Moon. A few seconds after that, the Moon moved to cover all of Jupiter. A few minutes after that, Jupiter reappeared on the other side of the Moon, and even a few minutes after that the Moon moved completely away from Jupiter. Although hard to catch, planes cross in front of the Moon quite frequently, but the Moon won't eclipse Jupiter again for another three years.

Il Flash del meteorite del 15 febbraio caduto su Chelyabinsk ...

...ripreso da un fotografo che stava facendo una sessione di foto del paesaggio invernale...
Il bolide è stimato di 15 mt di diametro... Il più grosso caduto dall'evento di Tunguska...

Chelyabinsk Meteor Flash

Image Credit & Copyright: Marat Ahmetvaleev

Explanation: A meteoroid fell to Earth on February 15, streaking some 20 to 30 kilometers above the city of Chelyabinsk, Russia at 9:20am local time. Initially traveling at about 20 kilometers per second, its explosive deceleration after impact with the lower atmosphere created a flash brighter than the Sun. This picture of the brilliant bolide (and others of its persistent trail) was captured by photographer Marat Ametvaleev, surprised during his morning sunrise session creating panoramic images of the nearby frosty landscape. An estimated 500 kilotons of energy was released by the explosion of the 17 meter wide space rock with a mass of 7,000 to 10,000 tons. Actually expected to occur on average once every 100 years, the magnitude of the Chelyabinsk event is the largest known since the Tunguska impact in 1908.

Come faremo a deviare gli asteroidi killer...

...Con questo "trattore gravitazionale" qui descritto con un'immagine artistica...
(da Astronomy Picture of the Day)

Gravitational Tractor

Illustration Credit & Copyright: Dan Durda (FIAAA, B612 Foundation)

Explanation: How would you change the course of an Earth-threatening asteroid? One possibility - a massive spacecraft that uses gravity as a towline - is illustrated in this artist's vision of a gravitational tractor in action. In the hypothetical scenario worked out in 2005 by Edward Lu and Stanley Love at NASA's Johnson Space Center, a 20 ton nuclear-electric spacecraft tows a 200 meter diameter asteroid by simply hovering near the asteroid. The spacecraft's ion drive thrusters are canted away from the surface. Their slight but steady thrust would gradually and predictably alter the course of the tug and asteroid, coupled by their mutual gravitational attraction. While it sounds like the stuff of science fiction, ion drives do power existing spacecraft. One advantage of using a gravitational tractor is that it would work regardless of the asteroid's structure. Given sufficient warning and time, a gravitational tractor could deflect the path of an asteroid known to be on a collision course enough to miss planet Earth.

Se non avete mai visto Mercurio....

Guardate questa bella foto che descrive, con scatti multipli fatti a distanza di giorni, come è apparso l'elusivo pianeta nel marzo 2000 al tramonto fotografato nei pochi minuti in cui era visibile. La foto rappresenta quindi il suo spostamento nel cielo osservato durante un mese...


Mercury on the Horizon

Image Credit & Copyright: Juan Carlos Casado

Explanation: Have you ever seen the planet Mercury? Because Mercury orbits so close to the Sun, it never wanders far from the Sun in Earth's sky. If trailing the Sun, Mercury will be visible low on the horizon for only a short while after sunset. If leading the Sun, Mercury will be visible only shortly before sunrise. So at certain times of the year an informed skygazer with a little determination can usually pick Mercury out from a site with an unobscured horizon. Above, a lot of determination has been combined with a little digital manipulation to show Mercury's successive positions during March of 2000. Each picture was taken from the same location in Spain when the Sun itself was 10 degrees below the horizon and superposed on the single most photogenic sunset. Currently, Mercury is visible in the western sky after sunset, but will disappear in the Sun's glare after a few days

Una bella cometa illumina il cielo australe...

È la cometa Lemmon, che qui brilla accanto alla Piccola Nube di Magellano e all' ammasso globulare 47 del Tucano... Nei prossimi mesi l'astro si sposterà verso i nostri cieli boreali...


Sweeping Through Southern Skies

Image/Video Credit & Copyright: Alex Cherney (Terrastro, TWAN)

Explanation: For now, Comet Lemmon (C/2012 F6a), and Comet PanSTARRS (C/2011 L4) are sweeping through southern skies. Lemmon's lime green coma and thin tail are near the left edge of this telephoto scene, a single frame from a timelapse video (vimeo here) recorded on February 12, tracking its motion against the background stars. Comet Lemmon's path brought it close to the line-of-sight to prominent southern sky treasures the Small Magellanic Cloud and globular cluster 47 Tucanae (right).

Se non avete mai visto due paraseleni, eccoli sull'Alaska...

... fotografati dall'Alaska due riflessi della Luna ai bordi dell'Halo provocato dai ghiacci in atmosfera... Vengono chiamati "Paraselene" ( o ...seleni) ad imitazione del parelio, fenomeno simile ma che si verifica con il Sole.

Alaskan Moondogs

Image Credit & Copyright: Sebastian Saarloos

Explanation: Moonlight illuminates a snowy scene in this night land and skyscape made on January 17 from Lower Miller Creek, Alaska, USA. Overexposed near the mountainous western horizon is the first quarter Moon itself, surrounded by an icy halo and flanked left and right by moondogs. Sometimes called mock moons, a more scientific name for the luminous apparations is paraselenae (plural). Analogous to a sundog or parhelion, a paraselene is produced by moonlight refracted through thin, hexagonal, plate-shaped ice crystals in high cirrus clouds. As determined by the crystal geometry, paraselenae are seen at an angle of 22 degrees or more from the Moon. Compared to the bright lunar disk, paraselenae are faint and easier to spot when the Moon is low.

La stazione spaziale attraversa il cielo estivo di Argentina

ISS and the Summer Milky Way

Image Credit & Copyright: Luis Argerich

Explanation: Clouds on a summer night frame this sea and skyscape, recorded earlier this month near Buenos Aires, Argentina. But planet Earth's clouds are not the only clouds on the scene. Starry clouds and nebulae along the southern hemisphere's summer Milky Way arc above the horizon, including the dark Coal Sack near the Southern Cross and the tantalizing pinkish glow of the Carina Nebula. Both the Large (top center) and Small Magellanic Clouds are also in view, small galaxies in their own right and satellites of the Milky Way up to 200,000 light-years distant. Alpha star of the Carina constellation and second brightest star in Earth's night, Canopus shines above about 300 light-years away. Still glinting in sunlight at an altitude of 400 kilometers, the orbiting International Space Station traces a long streak through the single, 5 minute, star-tracking exposure.

Il computer portatile del 1.mo secolo avanti Cristo....

Il meccanismo di Antikythera

Credit & Licenza: Wikipedia

Spiegazione: Che cosa è? E 'stato trovato in fondo al mare a bordo di una nave greca. La sua apparente complessità ha provocato decenni di studio, anche se alcune delle sue funzioni sono ancora rimaste sconosciute. Immagini a raggi X del dispositivo hanno confermato la natura del meccanismo di Antikythera, e scoperto varie funzioni sorprendenti. Il meccanismo di Antikythera è stato scoperto essere un computer meccanico di precisione, un progetto impossibile, nell'80 aC, quando la nave che lo trasportava affondò. Le sue ruote e ingranaggi creavano un planetario portatile del cielo che poteva prevedere i percorsi di stelle e pianeti, così come le eclissi lunari e solari. Il meccanismo di Antikythera, qui mostrato, è di 33 centimetri di altezza e, pertanto, di dimensioni simili a un grande libro ( o a un portatile...)

Quanti i pianeti simili alla Terra?

Illustrazione Credit: NASA / Ames / JPL-Caltech

Quanto sono comuni i pianeti delle dimensioni della Terra? Abbastanza comuni, secondo le estrapolazioni di nuovi dati presi dalla sonda orbitante Kepler della NASA. Modelli dei computer attuali indicano che almeno una su dieci stelle hanno in orbita un pianeta delle dimensioni della Terra, rendendo la nostra Via Lattea la patria di oltre dieci miliardi di Terre. Purtroppo, questa stima si applica in modo efficace solo ai pianeti che si trovino ad una distanza all'interno dell'orbita di Mercurio. Questo istogramma rappresenta la frazione stimata di stelle che hanno pianeti che orbitano attorno di varie dimensioni. Il numero di stelle simili al Sole, con pianeti simili alla Terra in orbite simili alla Terra è sicuramente molto meno. Ma anche così, Kepler ha appena annunciato la scoperta di altri quattro di questi pianeti...

Che meraviglia il Doppio Ammasso di Perseo...!

A Double Star Cluster

Image Credit & Copyright: F. Antonucci, M. Angelini, & F. Tagliani, ADARA Astrobrallo

Explanation: Few star clusters are seen to be so close to each other. Some 7,000 light-years away, though, this pair of open or galactic star clusters is an easy binocular target, a lovely starfield in the northern constellation Perseus. Also visible to the unaided eye from dark sky areas, it was cataloged in 130 BC by Greek astronomer Hipparchus. Now known as h and chi Persei, or NGC 869 (above right) and NGC 884, the clusters themselves are separated by only a few hundred light-years and contain stars much younger and hotter than the Sun. In addition to being physically close together, the clusters' ages based on their individual stars are similar - evidence that both clusters were likely a product of the same star-forming region.

Notte d'inverno nella Yosemite Valley... Buon Natale!

Yosemite Winter Night

Image Credit & Copyright: Wally Pacholka (AstroPics.com, TWAN)

Explanation: In this evocative night skyscape a starry band of the Milky Way climbs over Yosemite Valley, Sierra Nevada Range, planet Earth. Jupiter is the brightest celestial beacon on the wintry scene, though. Standing nearly opposite the Sun in the constellation Taurus, the wandering planet joins yellowish Aldebaran and the Hyades star cluster. Below, Orion always comes up sideways over a fence of mountains. And from there the twin stars of Gemini rise just across the Milky Way. As this peaceful winter night began, they followed Auriga the charioteer, its alpha star Capella near the top of the frame.

In attesa della nuova Grande Cometa prevista per il 2013...

... continuiamo a stupirci con la Hale Bopp del 1997...

Comet Hale-Bopp Over Val Parola Pass

Image Credit & Copyright: A. Dimai, (Col Druscie Obs.), AAC

Explanation: Comet Hale-Bopp, the Great Comet of 1997, became much brighter than any surrounding stars. It was seen even over bright city lights. Away from city lights, however, it put on quite a spectacular show. Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains surrounding Cortina d'Ampezzo, Italy. Comet Hale-Bopp's blue ion tail, consisting of ions from the comet's nucleus, is pushed out by the solar wind. The white dust tail is composed of larger particles of dust from the nucleus driven by the pressure of sunlight, that orbit behind the comet. Observations showed that Comet Hale-Bopp's nucleus spins about once every 12 hours. A comet that may well exceed Hale-Bopp's peak brightness is expected to fall into the inner Solar System next year.

Orione sopra la piramide...maya!

Orion over El Castillo

Image Credit & Copyright: Stéphane Guisard (Los Cielos de America, TWAN) Credits: D. Flores and B. Pichardo (Inst. Astronomia UNAM), P. Sánchez and R. Nafate (INAH)

Avete mai osservato un "pilastro" solare? Eccolo!

A Sun Pillar Over Sweden

Image Credit & Copyright: Göran Strand


Explanation: Have you ever seen a sun pillar? When the air is cold and the Sun is rising or setting, falling ice crystals can reflect sunlight and create an unusual column of light. Ice sometimes forms flat, six-sided shaped crystals as it falls from high-level clouds. Air resistance causes these crystals to lie nearly flat much of the time as they flutter to the ground. Sunlight reflects off crystals that are properly aligned, creating the sun-pillar effect. In the above picture taken last week, a sun-pillar reflects light from a Sun setting over Östersund, Sweden.

Pioggia di Geminidi...

When Gemini Sends Stars to Paranal

Image Credit & Copyright: Stéphane Guisard (Los Cielos de America), TWAN

Explanation: From a radiant point in the constellation of the Twins, the annual Geminid meteor shower rained down on planet Earth this week. Recorded near the shower's peak in the early hours of December 14, this skyscape captures Gemini's lovely shooting stars in a careful composite of 30 exposures, each 20 seconds long, from the dark of the Chilean Atacama Desert over ESO's Paranal Observatory. In the foreground Paranal's four Very Large Telescopes, four Auxillary Telescopes, and the VLT Survey telescope are all open and observing. The skies above are shared with bright Jupiter (left), Orion, (top left), and the faint light of the Milky Way. Dust swept up from the orbit of active asteroid 3200 Phaethon, Gemini's meteors enter the atmosphere traveling at about 22 kilometers per second.

Umbra World

Umbra World

Image Credit & Copyright: Dennis L. Mammana (TWAN)

Explanation: On the morning of November 14, sky gazers from around the world gathered on this little planet to stand in the dark umbral shadow of the Moon. Of course, the Moon cast the shadow during last month's total solar eclipse, and the little planet is actually a beach on Green Island off the coast of Queensland, Australia. The picture itself, the first little planet projection of a total solar eclipse, is a digitally warped and stitched wrap-around of 8 images covering 360x180 degrees. To make it, the intrepid photographer had to remember to shoot both toward and away(!) from the eclipse during the excitement of totality. Near this little planet's horizon, the eclipsed Sun is just above center, surrounded by the glowing solar corona. Venus can be spotted in the shadow-darkened sky toward the top of the frame. At bottom right, bright star Sirius shines at the tip of an alarmingly tall tree.