Η διαστημική φωτογραφία της ημέρας - Αρχείο

[Xenios]

Κλικ για μεγεθυνση

he Equal Night
Credit: STS-68 Crew, NASA

Explanation: Today, the Sun crosses the celestial equator heading south at 0951 UT. Known as the equinox, the astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. Equinox means equal night and with the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. Of course, for those in the south, the days will grow longer with the Sun marching higher in the sky as summer approaches. A few weeks after the September Equinox of 1994, the Crew of the shuttle orbiter Endeavor recorded this image of the Sun poised above the Earth's limb. Glare illuminates Endeavor's vertical tail (pointing toward the Earth) along with radar equipment in the payload bay.

Tomorrow's picture: youngs suns

Πηγή

[Xenios]

A Galactic Star Forming Region in Infrared
Credit: S. Carey (SSC/Caltech), JPL-Caltech, NASA

Explanation: How do stars form? To help study this complex issue, astronomers took a deep image in infrared light of an active part of our Milky Way Galaxy where star formation is rampant. In IRDC G11.11-0.11, thick clouds of dust and gas are congealing into stars that are so dark that humans living there would see an empty night sky. The image, though, taken last year by the Spitzer Space Telescope in infrared light, shows vast glowing fields of gas and dust, indicating that much of this dust is heated by forming stars. The centers of some clouds, such as the snake-like structure on the upper left, are so thick and cold that they are dark even in infrared light. Many of the red dots are glowing dust shrouds centered on very young newly formed stars. The unusual red sphere below the snake is actually a supernova remnant, the glowing shell of a young star so massive it evolved rapidly and exploded. The region spans about 150 light years and lies about 10,000 light years away toward the constellation of Sagittarius.

APOD editor to review best space pictures in Philadelphia Wednesday night
Tomorrow's picture: false dawn

Πηγη

[Xenios]

Zodiacal Light and the False Dawn
Credit & Copyright: Yuri Beletsky (ESO)

Explanation: An unusual triangle of light will be particularly bright near the eastern horizon before sunrise during the next two months for observers in Earth's northern hemisphere. Once considered a false dawn, this triangle of light is actually Zodiacal Light, light reflected from interplanetary dust particles. The triangle is clearly visible toward the left of the frame taken from the Paranal Observatory in Chile in July. Zodiacal dust orbits the Sun predominantly in the same plane as the planets: the ecliptic. Zodiacal light is so bright this time of year because the dust band is oriented nearly vertical at sunrise, so that the thick air near the horizon does not block out relatively bright reflecting dust. Zodiacal light is also bright for people in Earth's northern hemisphere in March and April just after sunset.

APOD editor to review best space pictures in Philadelphia tomorrow (Wednesday) night
Tomorrow's picture: harvest moon

Πηγή

[Xenios]

Κάντε κλικ για να δείτε σε μεγάλη ανάλυση αυτήν την μοναδική φωτογραφία

Saguaro Moon
Credit & Copyright: Stefan Seip (Astro Meeting)

Explanation: A Full Moon rising can be a dramatic celestial sight, and Full Moons can have many names. For example, tonight's Full Moon, the one nearest the autumnal equinox in the northern hemisphere, is popularly called the Harvest Moon. According to lore the name is a fitting one because farmers could work late into the night at the end of the growing season harvesting crops by moonlight. In the same traditions, the Full Moon following the Harvest Moon is the Hunter's Moon. But, recorded on a trip to the American southwest, this contribution to compelling images of moonrise is appropriately titled Saguaro Moon.

Tomorrow's picture: hole in the Sun

Πηγή

[Xenios]

Hole in the Sun
Credit: SOHO - EIT Consortium, ESA, NASA

Explanation: The dark expanse below the equator of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field opens freely into interplanetary space. Shown in false color, the picture was recorded on September 19th in extreme ultraviolet light by the EIT instrument onboard the space-based SOHO observatory. Studied extensively from space since the 1960s in ultraviolet and x-ray light, coronal holes are known to be the source of the high-speed solar wind, atoms and electrons that flow outward along the open magnetic field lines. The solar wind streaming from this coronal hole triggered colorful auroral displays on planet Earth begining late last week, enjoyed by spaceweather watchers at high latitudes.

Tomorrow's picture: Hole in Mars

Πηγή

[Xenios]

A Hole in Mars Close Up
Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: In a close-up from the HiRISE instrument onboard the Mars Reconnaissance Orbiter, this mysterious dark pit, about 150 meters across, lies on the north slope of ancient martian volcano Arsia Mons. Lacking raised rims and other impact crater characteristics, this pit and others like it were originally identified in visible light and infrared images from the Mars Odyssey and Mars Global Surveyor spacecraft. While the visible light images showed only darkness within, infrared thermal signatures indicated that the openings penetrated deep under the martian surface and perhaps were skylights to underground caverns. In this later image, the pit wall is partially illuminated by sunlight and seen to be nearly vertical, though the bottom, at least 78 meters below, is still not visible. The dark martian pits are thought to be related to collapse pits in the lava flow, similar to Hawaiian volcano pit craters.

Tomorrow's picture: Dawn Launch

Πηγή

[Gildor]

Ελπιζω να μη βγαλουν οι ξερετε-ποιοι τη θεωρια του 'Κουφιου Αρη"

[Xenios]

Dawn Launch Mosaic
Credit & Copyright: Randy Pollock

Explanation: Shortly after sunrise on Thursday at Cape Canaveral Air Force Station, the Dawn spacecraft began its journey to the asteroid belt, arcing eastward into a blue and cloudy sky. Dawn's voyage began on a conventional, chemically fueled Delta II rocket, but will continue with an innovative ion propulsion system. The spacecraft's extremely efficient ion engines will use electricity derived from solar power to ionize xenon atoms and generate a gentle but continuous thrust. After a four year interplanetary cruise, Dawn will orbit two small worlds, first Vesta and then Ceres. Vesta is one of the largest main belt asteroids, while nomenclature introduced by the International Astronomical Union in 2006 classifies nearly spherical Ceres as a dwarf planet.

Tomorrow's picture: big band

Πηγή

[Sleepy]

... μενω αφωνη... απιστευτο...

[Xenios]

A Milky Way Band
Credit & Copyright: John P. Gleason, Celestial Images

Explanation: Most bright stars in our Milky Way Galaxy reside in a disk. Since our Sun also resides in this disk, these stars appear to us as a diffuse band that circles the sky. The above panorama of a northern band of the Milky Way's disk covers 90 degrees and is a digitally created mosaic of several independent exposures. Scrolling right will display the rest of this spectacular picture. Visible are many bright stars, dark dust lanes, red emission nebulae, blue reflection nebulae, and clusters of stars. In addition to all this matter that we can see, astronomers suspect there exists even more dark matter that we cannot see.

Tomorrow's picture: galaxy next door

Πηγή

[Xenios]

Το μη επανδρωμένο διαστημόπλοιο Dawn προς τους Εστία και Δήμητρα, τους δύο μεγαλύτερους αστεροειδείς που βρίσκονται σε τροχιά γύρω από τον ήλιο εκτόξευσε χθες η ΝΑΣΑ. Το Dawn δεν κινείται με τα παραδοσιακά καύσιμα που χρησιμοποιούν τα διαστημόπλοια, αλλά με τρεις ηλεκτρικές μηχανές, οι οποίες παίρνουν ενέργεια από τον Ήλιο.

Είναι η το διαστημόπλοιο που είδαμε ατην χθεσινη φωτογραφία.

[Sleepy]

ωραιες ειναι ολες τους

[Xenios]

The Small Cloud of Magellan
Credit & Copyright: Stéphane Guisard

Explanation: Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan. These cosmic clouds are now understood to be dwarf irregular galaxies, satellites of our larger spiral Milky Way Galaxy. The Small Magellanic Cloud pictured above actually spans 15,000 light-years or so and contains several hundred million stars. About 210,000 light-years distant in the constellation Tucana, it is the fourth closest of the Milky Way's known satellite galaxies, after the Canis Major and Sagittarius Dwarf galaxies and the Large Magellanic Cloud. This gorgeous view also includes two foreground globular star clusters NGC 362 (top left) and 47 Tucanae. Spectacular 47 Tucanae is a mere 13,000 light-years away and seen here to the left of the Small Magellanic Cloud.

Tomorrow's picture: dark sun moving

Πηγή

[Xenios]

Tutulemma: Solar Eclipse Analemma
Credit & Copyright: Tunc Tezel and Cenk E. Tezel

Explanation: If you went outside at exactly the same time every day and took a picture that included the Sun, how would the Sun appear to move? With great planning and effort, such a series of images can be taken. The figure-8 path the Sun follows over the course of a year is called an analemma. With even greater planning and effort, the series can include a total eclipse of the Sun as one of the images. Pictured is such a total solar eclipse analemma or Tutulemma - a term coined by the photographers based on the Turkish word for eclipse. The composite image sequence was recorded from Turkey starting in 2005. The base image for the sequence is from the total phase of a solar eclipse as viewed from Side, Turkey on 2006 March 29. Venus was also visible during totality, toward the lower right.

Tomorrow's picture: Comet Encke's Big Ripoff

Πηγή

[Xenios]

Κλικ για animation

Comet Encke's Tail Ripped Off
Credit: Angelos Vourlidas (NRL) et al., SECCHI / STEREO, NASA

Explanation: Swinging inside the orbit of Mercury, on April 20th periodic comet Encke encountered a blast from the Sun in the form of a Coronal Mass Ejection (CME). When CMEs, enormous clouds of energetic particles ejected from the Sun, slam into Earth's magnetosphere, they often trigger auroral displays. But in this case, the collison carried the tail of the comet away. The tail was likely ripped off by interacting magnetic fields rather than the mechanical pressure of the collision. Clicking on the two panel image will play a movie gif of the remarkable event as recorded by the Heliospheric Imager onboard the STEREO A spacecraft. In the movie, the time between frames is about 45 minutes, while the frames span about 14x20 million kilometers at the distance of the comet. Of course, similar collisions have happened before as the ancient comet loops through its 3.3 year solar orbit. So don't worry, Encke's tail grows back!

Tomorrow's picture: traveling companion

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