Thursday, March 4, 2010

NGC 4565: Galaxy on Edge

Thursday, March 4, 2010 0 comments
Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy's bulging central core cut by obscuring dust lanes that lace NGC 4565's thin galactic plane. An assortment of other galaxies are included in the pretty field of view. Neighboring galaxy NGC 4562 is at the upper right. NGC 4565 itself lies about 40 million light-years distant, spanning some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.

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Pauli Exclusion Principle: Why You Don't Implode 0 comments

Why doesn't matter just bunch up? The same principle that keeps neutron stars and white dwarf stars from imploding also keeps people from imploding and makes normal matter mostly empty space. The observed reason is known as the Pauli Exclusion Principle. The principle states that identical fermions -- one type of fundamental matter -- cannot be in the same place at the same time and with the same orientation. The other type of matter, bosons, do not have this property, as demonstrated clearly by recently created Bose-Einstein condensates. Earlier this decade, the Pauli Exclusion Principle was demonstrated graphically in the above picture of clouds of two isotopes of lithium -- the left cloud composed of bosons while the right cloud is composed of fermions. As temperature drops, the bosons bunch together, while the fermions better keep their distance. The reason why the Pauli Exclusion Principle is true and the physical limits of the principle are still unknown.

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Wednesday, March 3, 2010

The International Space Station from Above

Wednesday, March 3, 2010 0 comments
The International Space Station (ISS) is the largest human-made object ever to orbit the Earth. The ISS is so large that it can be seen drifting overhead with the unaided eye, and is frequently imaged from the ground in picturesque fashion. Last month, the station was visited again by space shuttle, which resupplied the station and added a new module. The ISS is currently operated by the Expedition 22 crew, now consisting five astronauts including two supplied by USA's NASA, two by Russia's RKA, and one by Japan's JAXA. After departing the ISS, the crew of the space shuttle Endeavour captured the above spectacular vista of the orbiting space city high above the clouds, waters, and lands of Earth. Visible components include modules, trusses, and expansive solar arrays that gather sunlight that is turned into needed electricity.

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Tuesday, March 2, 2010

M78 and Reflecting Dust Clouds in Orion

Tuesday, March 2, 2010 0 comments
An eerie blue glow and ominous columns of dark dust highlight M78 and other bright reflection nebula in the constellation of Orion. The dark filamentary dust not only absorbs light, but also reflects the light of several bright blue stars that formed recently in the nebula. Of the two reflection nebulas pictured above, the more famous nebula is M78, in the image center, while NGC 2071 can be seen to its lower left. The same type of scattering that colors the daytime sky further enhances the blue color. M78 is about five light-years across and visible through a small telescope. M78 appears above only as it was 1600 years ago, however, because that is how long it takes light to go from there to here. M78 belongs to the larger Orion Molecular Cloud Complex that contains the Great Nebula in Orion and the Horsehead Nebula.

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Monday, March 1, 2010

Slope Streaks in Acheron Fossae on Mars

Monday, March 1, 2010 0 comments
What creates these picturesque dark streaks on Mars? No one knows for sure. A leading hypothesis is that streaks like these are caused by fine grained sand sliding down the banks of troughs and craters. Pictured above, dark sand appears to have flowed hundreds of meters down the slopes of Acheron Fossae. The sand appears to flow like a liquid around boulders, and, for some reason, lightens significantly over time. This sand flow process is one of several which can rapidly change the surface of Mars, with other processes including dust devils, dust storms, and the freezing and melting of areas of ice. The above image was taken by the HiRise camera on board the Mars Reconnaissance Orbiter which has been orbiting Mars since 2006. Acheron Fossae is a 700 kilometer long trough in the Diacria quadrangle of Mars.

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