2007 March 23


Touran Sunrise

Explanation:
Clouds covered the eastern horizon on Monday, when the Sun rose over the expansive Touran Wildlife Reserve in northeastern Iran. Of course, on that day the Moon rose with the Sun, creating a widely enjoyed partial solar eclipse. Along with a mountainous horizon, the cloud cover lent a dramatic aspect to this eclipse sunrise and made it possible for astronomer Babak Tafreshi to record these telephoto images without using a filter. Advancing north in planet Earth's sky, the Sun itself was also approaching the equinox, the astronomical marker for the first day of northern hemisphere spring and the beginning of Norouz, the Persian New Year.

2007 March 24


Lisbon Moonset

Explanation:
Brilliant Venus, a slender crescent Moon, and lights along the Ponte 25 de Abril glow against the western twilight in this lovely moonset scene from Lisbon, Portugal, recorded on March 20. In fact, such serene views were enjoyed across planet Earth this week, as the young Moon remained near the setting Sun following a partial solar eclipse, and Venus ruled as the evening star. Because of strong Earthshine - light from the sunlit Earth - even the Moon's night side is clearly visible in the picture. The Ponte 25 de Abril is a 2.3 kilometer long suspension bridge across the Tagus river, often compared to the Golden Gate bridge in San Francisco, USA.

2007 March 25


Welcome to Planet Earth

Explanation:
Welcome to Planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen. The above picture of Earth, dubbed Blue Marble, was taken from Apollo 17 in 1972 and features Africa and Antarctica. It is thought to be one of the most widely distributed photographs of any kind. Earth has a single large Moon that is about 1/4 of its diameter and, from the planet's surface, is seen to have almost exactly the same angular size as the Sun. With its abundance of liquid water, Earth supports a large variety of life forms, including potentially intelligent species such as dolphins and humans. Please enjoy your stay on Planet Earth.

2007 March 26


Bullet Pillars in Orion

Explanation:
Why are bullets of gas shooting out of the Orion Nebula? Nobody is yet sure. First discovered in 1983, each bullet is actually about the size of our Solar System, and moving at about 400 km/sec from a central source dubbed IRc2. The age of the bullets, which can be found from their speed and distance from IRc2, is very young -- typically less than 1,000 years. As the bullets rip through the interior of the Orion Nebula, a small percentage of iron gas causes the tip of each bullet to glow blue, while each bullet leaves a tubular pillar that glows by the light of heated hydrogen gas. Pictured above, the Orion bullets were captured in unprecedented detail by the adaptive optics technology of the Gemini North telescope. M42, the Orion Nebula, is the closest major star forming region to us and filled with changing dust, gas, and bright stars. The Orion Nebula, is located about 1,500 light years away and can be seen with the unaided eye toward the constellation of Orion.

2007 March 27


Enceladus Creates Saturn's E Ring

Explanation:
The active moon Enceladus appears to be making Saturn's E ring. An amazing picture showing the moon at work was taken late last year by the Saturn-orbiting Cassini spacecraft and is shown above. Enceladus is the dark spot inside the bright flare, right near the center of Saturn's E ring. Streams of ice and water vapor can be seen pouring off Enceladus into the E ring. The above bright image of the normally faint E-ring was made possible by aligning Cassini so that Saturn blocked the Sun. From that perspective, small ring particles reflect incoming sunlight more efficiently. Cassini has now been orbiting Saturn for almost three years, and is scheduled to swoop by the unexpectedly cryovolcanic Enceladus at least several more times.

2007 March 28


NGC 1365: Majestic Island Universe

Explanation:
Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the chemical constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax galaxy cluster. This impressively sharp color image shows intense star forming regions at the ends of the bar and along the spiral arms, as well as details of dust lanes cutting across the galaxy's bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole.

2007 March 30


Three Galaxies and a Comet

Explanation:
Diffuse starlight and dark nebulae along the southern Milky Way arc over the horizon and sprawl diagonally through this gorgeous nightscape. The breath-taking mosaic spans a wide 100 degrees, with the rugged terrain of the Patagonia, Argentina region in the foreground. Along with the insider's view of our own galaxy, the image features our outside perspective on two irregular satellite galaxies - the Large and Small Magellanic Clouds. Recorded on January 28, the scene also captures the broad tail and bright coma of Comet McNaught, The Great Comet of 2007.

2007 March 31


Hale-Bopp: The Great Comet of 1997

Explanation:
Ten short years ago, Comet Hale-Bopp rounded the Sun and offered a dazzling spectacle in planet Earth's night. This stunning view, recorded shortly after the comet's perihelion passage on April 1, 1997, features the memorable tails of Hale-Bopp -- a whitish dust tail and blue ion tail. Here, the ion tail extends well over ten degrees across the northern sky, fading near the double star clusters in Perseus, while the head of the comet lies near Almach, a bright star in the constellation Andromeda. Do you remember Hale-Bopp? The photographer's sons do, pictured in the foreground at ages 12 and 15. In all, Hale-Bopp was reported as visible to the naked eye from roughly late May 1996 through September 1997.

2007 April 4


New Horizons at Io

Explanation:
Spewed from a volcano, a complex plume rises over 300 kilometers above the horizon of Jupiter's moon Io in this image from cameras onboard the New Horizons spacecraft. The volcano, Tvashtar, is marked by the bright glow (about 1 o'clock) at the moon's edge, beyond the terminator or night/day shadow line. The shadow of Io cuts across the plume itself. Also capturing stunning details on the dayside surface, the high resolution image was recorded when the spacecraft was 2.3 million kilometers from Io. Later it was combined with lower resolution color data by astro-imager Sean Walker to produce this sharp portrait of the solar system's most active moon. Outward bound at almost 23 kilometers per second, the New Horizons spacecraft should cross the orbit of Saturn in June next year, and is ultimately destined to encounter Pluto in 2015.

2007 April 9


Aurora Over Alaska

Explanation:
Higher than the highest mountain, higher than the highest airplane, lies the realm of the aurora. Aurora rarely reach below 60 kilometers, and can range up to 1000 kilometers. Aurora light results from solar shockwave causing energetic electrons and protons to striking molecules in the Earth's atmosphere. Frequently, when viewed from space, a complete aurora will appear as a circle around one of the Earth's magnetic poles. The above digitally enhanced photograph was taken in 2005 January shows a spectacular aurora borealis above the frozen landscape of Bear Lake, Alaska, USA. The above image was voted Wikipedia Commons Picture of the Year for 2006.