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Comment by doone on May 4, 2012 at 6:30am

Fermi Epicycles: The Vela Pulsar's Path 
Credit: NASA, DOE, International Fermi LAT Collaboration

Explanation: Exploring the cosmos at extreme energies, the Fermi Gamma-ray Space Telescope orbits planet Earth every 95 minutes. By design, it rocks to the north and then to the south on alternate orbits in order to survey the sky with its Large Area Telescope (LAT). The spacecraft also rolls so that solar panels are kept pointed at the Sun for power, and the axis of its orbit precesses like a top, making a complete rotation once every 54 days. As a result of these multiple cycles the paths of gamma-ray sources trace out complex patterns from the spacecraft's perspective, like this mesmerising plot of the path of the Vela Pulsar. Centered on the LAT instrument's field of view, the plot spans 180 degrees and follows Vela's position from August 2008 through August 2010. The concentration near the center shows that Vela was in the sensitive region of the LAT field during much of that period. Born in the death explosion of a massive star within our Milky Way galaxy, the Vela Pulsar is a neutron star spinning 11 times a second, seen as the brightest persistent source in the gamma-ray sky.

Comment by doone on May 3, 2012 at 7:22am

M106 Close Up 
Credit: Composite Image Data - Hubble Legacy Archive; Adrian Zsilavec, Michelle Qualls, Adam Block / NOAO / AURA / NSF 
Processing - André van der Hoeven

Explanation: Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106. Modern deep telescopic views reveal it to be an island universe: a spiral galaxy around 30 thousand light-years across located only about 21 million light-years beyond the stars of the Milky Way. Along with prominent dust lanes and a bright central core, this colorful composite image highlights youthful blue star clusters and reddish stellar nurseries that trace the galaxy's spiral arms. The high resolution galaxy portrait is a mosaic of data from Hubble's sharp ACS camera combined with groundbased color image data. M106 (aka NGC 4258) is a nearby example of the Seyfert class of active galaxies, seen across the spectrum from radio to X-rays. Energetic active galaxies are powered by matter falling into a massivecentral black hole.

Comment by Michel on May 2, 2012 at 10:25am

Saturn's Moon Helene in Color 
Image Credit: NASA/JPL/SSI; Color Composite: Daniel Machácek

Explanation: Although its colors may be subtle, Saturn's moon Helene is an enigma in any light. The moon was imaged in unprecedented detail last June as the robotic Cassini spacecraft orbiting Saturn swooped to within a single Earth diameter of the diminutive moon. Although conventional craters and hills appear, the above image also shows terrain that appears unusually smooth and streaked. Planetary astronomers are inspecting these detailed images of Helene to glean clues about the origin and evolution of the 30-km across floating iceberg. Helene is also unusual because it circles Saturn just ahead of the large moon Dione, making it one of only four known Saturnian moons to occupy a gravitational well known as a stable Lagrange point.

Comment by Chris on May 1, 2012 at 1:24am

That is a beautiful picture doone. I saved it for later use (maybe a screensaver). The aurora coming from true north makes sense since that's where the weakest magnetic field is.

Comment by Neal on April 30, 2012 at 11:44pm

That's fun.

Comment by doone on April 30, 2012 at 10:06pm

"Doctor Who" Metal Cover Is The Awesomest Thing In The Universe

Traveling through time and space has never sounded so badass. Let's open this time vortex up

Comment by Michel on April 30, 2012 at 9:28am

Moon, Milky Way, and ALMA TelescopeCredit: ESO/S. Guisard (www.eso.org/~sguisard)This amazing panorama depicts the site of ALMA, the Atacama Large Millimeter/submillimeter Array, in the Chilean Andes. When ALMA is complete, it will have 54 of the 12-meter-diameter dishes shown. Above the array, the arc of the Milky Way glistens while the moon bathes the scene in an eerie light. ESO Photo Ambassador Stéphane Guisard took the shot, released April 23, 2012. Click the picture to see a larger version of the astounding image.

Comment by Michel on April 30, 2012 at 9:08am

This is spectacular!!

I've been to the north of Iceland for a few days but it was snowing heavily... no sky to speak of. 

Comment by Adriana on April 30, 2012 at 9:07am

What a beautiful photo!

Comment by doone on April 30, 2012 at 8:07am

Aurora Over Raufarhöfn 
Image Credit & Copyright: Stephane Vetter (Nuits sacrees)

Explanation: It was all lined up even without the colorful aurora exploding overhead. If you follow the apex line of the recently deployed monuments of Arctic Henge in Raufarhöfn in northern Iceland from this vantage point, you will see that they point due north. A good way to tell is to follow their apex line to the line connecting the end stars of the Big Dipper, Merak and Dubhe, toward Polaris, the bright star near the north spin axis of the Earth projected onto the sky. By design, from this vantage point, this same apex line will also point directly at the midnight sun at its highest point in the sky just during the summer solstice of Earth's northern hemisphere. In other words, the Sun will not set at Arctic Henge during the summer solstice in late June, and at its highest point in the skyit will appear just above the aligned vertices of this modern monument. The above image was taken in late March during a beautiful auroral storm.

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