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۱۳۹۱ آذر ۲۹, چهارشنبه

2012 December 19
See Explanation.  Clicking on the picture will download 
the highest resolution version available.
NGC 5189: An Unusually Complex Planetary Nebula 
Image Credit: NASAESAHubble Heritage Team (STScI/AURA)
Explanation: Why is this nebula so complex? When a star like our Sun is dying, it will cast off its outer layers, usually into a simple overall shape. Sometimes this shape is a sphere, sometimes a double lobe, and sometimes a ring or a helix. In the case of planetary nebula NGC 5189, however, no such simple structure has emerged. To help find out why, the Earth-orbiting Hubble Space Telescope recently observed NGC 5189 in great detail. Previous findings indicated the existence of multiple epochs of material outflow, including a recent one that created a bright but distorted torus running horizontally across image center. Results appear consistent with a hypothesis that the dying star is part of a binary star system with a precessing symmetry axis. Given this new data, though, research is sure to continue. NGC 5189 spans about three light years and lies about 3,000 light years away toward the southern constellation of the Fly (Musca).

2012 December 18 
See Explanation.  Clicking on the picture will download 
the highest resolution version available.
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 cloudsAir 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 ÖstersundSweden.

2012 December 17
See Explanation.  Clicking on the picture will download 
the highest resolution version available.
NGC 922: Collisional Ring Galaxy 
Image Credit: NASAESAAcknowledgement: Nick Rose
Explanation: Why does this galaxy have so many big black holes? No one is sure. What is sure is that NGC 922 is a ring galaxy created by the collision of a large and small galaxy about 300 million years ago. Like a rock thrown into a pond, the ancient collision sent ripples of high density gas out from the impact point near the center that partly condensed into stars. Pictured above is NGC 922 with its beautifully complex ring along the left side, as imaged recently by the Hubble Space Telescope. Observations of NGC 922 with the Chandra X-ray Observatory, however, show several glowing X-ray knotsthat are likely large black holes. The high number of massive black holes was somewhat surprising as the gas composition in NGC 922 -- rich in heavy elements -- should have discouraged almost anything so massive from forming. Research is sure to continue. NGC 922 spans about 75,000 light years, lies about 150 million light years away, and can be seen with a small telescope toward the constellation of the furnace (Fornax).

2012 December 16
See Explanation.  Clicking on the picture will download 
the highest resolution version available.
MWC 922: The Red Square Nebula 
Image Credit & Copyright: Peter Tuthill (Sydney U.) & James Lloyd (Cornell)
Explanation: What could cause a nebula to appear square? No one is quite sure. The hot star system known as MWC 922, however, appears to be embedded in a nebula with just such a shape. Theabove image combines infrared exposures from the Hale Telescope on Mt. Palomar in California, and the Keck-2 Telescope on Mauna Kea in Hawaii. A leading progenitor hypothesis for the square nebulais that the central star or stars somehow expelled cones of gas during a late developmental stage. For MWC 922, these cones happen to incorporate nearly right angles and be visible from the sides. Supporting evidence for the cone hypothesis includes radial spokes in the image that might run along the cone walls. Researchers speculate that the cones viewed from another angle would appear similar to the gigantic rings of supernova 1987A, possibly indicating that a star in MWC 922 might one day itself explode in a similar supernova.

2012 December 15
See Explanation.  Clicking on the picture will download
 the highest resolution version available.
When Gemini Sends Stars to Paranal 
Image Credit & CopyrightStéphane 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.

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۱۳۹۱ آذر ۲۶, یکشنبه

اشتراك ايميلي هفته‌نامه امرداد براي فارسي‌زبانان
«امرداد» را پيش از چاپ بخوانيد
خبرنگار امرداد - بهنام مرادیان :

دوستداران فرهنگ و تاريخ ايران‌زمين مي‌توانند از اين پس، نسخه الكترونيكي هفته‌نامه‌ي امرداد را پيش از چاپ روي رايانه شخصي خود بخوانند.

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جاري:‌ ١٢٤٣٤٨٤٧١ (قابل واريز در تمامي شعب بانك تجارت در سراسر كشور)

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  • آلمان - بن - كورش كشاورزي - ايميل: burg_germany@yahoo.de
  • فرانسه - پاريس - پدرام نيكنام - ايميل: hamyare_amordad@yahoo.fr
  • انگلستان – لندن – فرنگيس كاوياني – ايميل: Amordadlondon@yahoo.co.uk
  • سوئد – استكهلم – موبد كامران جمشيدي – ايميل: kamran.jamshidi@gmail.com
  • استراليا - سيدني - مهرانگيز ضياتبري - ايميل: mary_ziatabari@hotmail.com
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  • كانادا - كلگري - بهار سلامتي - ايميل: bsalamaty@gmail.com
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۱۳۹۱ آذر ۲۴, جمعه

Astronomy Picture of the Day 2012 December 14

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 toward the top of the frame. At bottom right, bright star Sirius shines at the tip of an alarmingly tall tree.

۱۳۹۱ آذر ۲۳, پنجشنبه

Persian Gulf & Moon

 acquired September 30, 2012  

acquired October 5, 2012

acquired October 10, 2012
acquired October 15, 2012

The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured these nighttime views of the Persian Gulf region on September 30, October 5, October 10, and October 15, 2012. The images are from the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as gas flares, auroras, wildfires, city lights, and reflected moonlight.
Each image includes an inset of the Moon in four different phases. September 30 shows the Persian Gulf by the light of the full Moon; October 15 shows the effects of a new Moon. As the amount of moonlight decreases, some land surface features become harder to detect, but the lights from cities and ships become more obvious. Urbanization is most apparent along the northeastern coast of Saudi Arabia, in Qatar, and in the United Arab Emirates (UAE). In Qatar and UAE, major highways can even be discerned by nighttime lights.
In eighteenth-century England, a small group of entrepreneurs, inventors and free thinkers—James Watt and Charles Darwin’s grandfathers among them—started a club. They named it the Lunar Society, and the “lunaticks” scheduled their dinner meetings on evenings of the full Moon. The timing wasn’t based on any kind of superstition, it was based on practicality. In the days before electricity, seeing one’s way home after dark was far easier by the light of a full Moon. In the early twenty-first century, electricity has banished the need for such careful scheduling, but the light of the full Moon still makes a difference.
  1. References

  2. Uglow, J. (2002) The Lunar Men: Five Friends Whose Curiosity Changed the World. New York: Farrar, Straus and Giroux
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott.

Milky Way Over Quiver Tree Forest

2012 December 12  
Milky Way Over Quiver Tree Forest 
Image Credit & Copyright: Florian Breuer
Explanation: In front of a famous background of stars and galaxies lies some of Earth's more unusual trees. Known as quiver trees, they are actually succulent aloe plants that can grow to tree-like proportions. The quiver tree name is derived from the historical usefulness of their hollowed branches as dart holders. Occurring primarily in southern Africa, the trees pictured in the above 16-exposure composite are in Quiver Tree Forest located in southern Namibia. Some of the tallest quiver trees in the park are estimated to be about 300 years old. Behind the trees is light from the small town ofKeetmanshoopNamibia. Far in the distance, arching across the background, is the majestic central band of our Milky Way Galaxy. Even further in the distance, visible on the image left, are the Large andSmall Magellanic Clouds, smaller satellite galaxies of the Milky Way that are prominent in the skies of Earth's southern hemisphere.

Last Repetitive Day this Century: For one second today the date and time will be 12/12/12 12:12:12. 

Behold the 12/12/12 12:12 Baby

This baby is so fresh she doesn’t even have a name yet, but she definitely has a number. Baby-girl Patterson entered the world at 12 minutes after noon today at NewYork-Presbyterian/Weill Cornell hospital. (The clock-looking thing on the right in the photo above is a timer, not a clock.)
The little one weighs just over six pounds. She has twin siblings. We wish her health and happiness a dozen times over. Her parents are Michael and Olivia Patterson of the Upper East Side. What should they name her?

۱۳۹۱ آذر ۲۲, چهارشنبه

چرا دارم وبلاگ می نویسم؟ خود خواهی؟لج بازی با خودم؟یا پر کردن جای تنهاییکه از وقتی یادم میاد با من بوده؟
شاید گفتن حرف هایی که سال ها توی مغزم نگه داشتم. باشه می نویسم تا ببینم تا کجا پیش میرم

تصویر نجومی ماه Astronomy Picture of the months

رجل الجبار و سحابی سر جادوگر
1 نوامبر 2012

سیاهچاله در کهکشان راه شیری
2 نوامبر 2012

  ماه شکارچی‌ها بر فراز آلپ
3 نوامبر 2012

ابرهای عدسی شکل بر فراز واشنگتن
4 نوامبر 2012

دیون قمر زحل با کمی رنگ
5 نوامبر 2012

متون: قمر تخم‌مرغی شکل و صاف زحل
6 نوامبر 2012

Arp 188 و دم بچه قورباغه
8 نوامبر 2012

در قلب "ملوت 15"
9 نوامبر 2012

کهکشان حلقه قطبی NGC 660
10 نوامبر 2012

دانه‌های بیلی در نزدیکی زمان خورشید گرفتی کلی
11 نوامبر 2012

شهاب و رنگین‌کمان ماه بر فراز آبشار والامن
12 نوامبر 2012

گرفت خورشید در کوینزلند
15 نوامبر 2012

توالی سایه ماه
16 نوامبر 2012

مثل یک الماس در آسمان
17 نوامبر 2012

NGC 6357: کلیسایی برای ستارگان پر جرم
18 نوامبر 2012

شهاب‌های اسدی بر فراز دره بناهای سنگی
19 نوامبر 2012

هاله‎ای دور ماه
20 نوامبر 2012

حلقه الماس و نوارهای سایه
21 نوامبر 2012

شبی با شهاب اسدی بلند
22 نوامبر 2012

سحابی پیپ
23 نوامبر 2012

NGC 1365: مارپیچی با شکوه با ابرنواختر
24 نوامبر 2012

شن‌های تیره‌ آبشارگونه در مریخ
25 نوامبر 2012

حلقه‌های سحابی پرده
26 نوامبر 2012

مشتری درخشان در ثور
27 نوامبر 2012

مشتری و یو
28 نوامبر 2012

ماه بزرگ در برابر ماه کوچک
29 نوامبر 2012

ابرها در قو (دجاجه)
30 نوامبر 2012

مولفان و ویراستاران: (Robert Nemiroff (MTU) - Jerry Bonnell (UMCP
مسئول ناسا: Phillip Newman
حقوق کاربری ویژه
سیاست حریم شخصی وب ناسا و نکات مهم
خدمتی از: ASD در NASA / GSFC
و دانشگاه تکنولوژی میشیگان

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