the-actual-universe:

The Great Sloan WallThe Sloan Digital Sky Survey (SDSS) is a recent telescope that has been mapping the positions and structures of many hundreds of millions of galaxies revealing incredible structures and creating the first 3D map of our universe. Galaxies are found to be forming in groups and clusters throughout the cosmos with some individual clusters containing thousands of galaxies. Many of these groups and clusters combined together form incredibly large gravitationally bound structures known as superclusters which can stretch out for hundreds of millions of light years!Structures of this nature were once thought to be the largest in existence. However, it is now hypothesised that these superclusters form even larger structures known as filaments or walls. This chaining of superclusters surrounds great areas of empty space creating boundaries within which no galaxies exist for millions of light years. But why are galaxies forming in this way? The answer, we believe… our mysterious friend dark matter.It is thought that superclusters of galaxies are forming along web-like strings of dark matter which make up our universe. This underlying web of dark matter is thought to sculpt the universe and give it structure; wherever dark matter filaments intersect, large halos grow and massive gravitational influences result. The large gravitational effect produced by this dark matter collects together ordinary matter into the clusters and superclusters we see around us.So it seems without dark matter the universe would not exist as it is today!The single largest structure discovered in the history of science is one of these filaments, known as The Great Sloan Wall; it was discovered by SDSS and contains the Hercules supercluster, the Coma supercluster and the Leo cluster and spans a mind boggling 1.4 billion light years across!Keeping in mind that one light year is the equivalent of approximately 9.46 trillion km (5.87 trillion miles) this is truly a testament to the incredible, inspirational power and scale of the universe and of the brilliance of the scientific method which revealed this magnificent wonder.This image is a computer simulation of filaments of dark matter, a cosmic web that is thought to structure the formation of galaxies and clusters within the universe.Here is a great video clip about the The Great Sloan Wall from the TV show “How the universe works” - DJGSourceImage credit - (Computer simulation) Ralf Kaehler, Oliver Hahn and Tom Abel (KIPAC))
beautifulmars:


To the Utmost Bounds of the Eternal Hills
end0skeletal:

(via 500px / Autumn Sunrise On The Deschutes by Sean Bagshaw)
distant-traveller:

Why is Comet ISON green?

Undoubtedly, you’ve been seeing the recent images of Comet ISON now that it is approaching its close encounter with the Sun on November 28. ISON is currently visible to space telescopes like the Hubble and amateur astronomers with larger telescopes. But you might be wondering why many images show the comet with a green-ish “teal” or blue-green color.
Amateur Astronomer Chris Schur has put together this great graphic which provides information on the spectra of what elements are present in the comet’s coma. The green color is a sign the comet is getting more active as gets closer to the Sun – meaning it is now putting on a good show for astronomers, and if it can continue to hold itself together, it might become one of the brightest comets in the past several years.
“ISON’s green color comes from the gases surrounding its icy nucleus,” says SpaceWeather.com’s Tony Phillips. “Jets spewing from the comet’s core probably contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C2). Both substances glow green when illuminated by sunlight in the near-vacuum of space. Both are normally colorless gases that fluoresce a green color when excited by energetic ultraviolet light in sunlight.
Normally reflected sunlight is rather flat and bland, and mostly that is what ISON is right now, reflected from dust. But labeled are two humps in the blue and green parts of the spectrum labeled “C2″ for a carbon molecule. This blue/green emission pair is what gives ISON the color.

Image credit: Chris Schur
the-actual-universe:

Galactic BullseyeMillions of years ago, a galactic bullseye produced the unusual form of NGC 922. A smaller galaxy officially known as 2MASXI J0224301-244443, plunged through the center of NGC 922 and right out the other side. In wide-field views of the NGC 922, you can still see it speeding away. As the small galaxy passed through the middle of NGC 922, it disrupted the clouds of gas, and triggered the formation of new stars whose radiation then lit up the remaining gas. The bright pink color of the resulting nebulae is a characteristic sign of this process, and is similar to the process going on inside neon signs.Typically when two galaxies are aligned just right, with the small one passing through the center of the larger one, the ring of nebulae should form a perfect circle, but usually the two galaxies are slightly off producing a ring like this one, that is noticeably brighter on one side.Hubble’s image of NGC 922 consists of a series of exposures taken in visible light with Hubble’s Wide Field Camera 3, and in visible and near-infrared light with the Wide Field and Planetary Camera 2.-ALTSourceImage Credit:NASA/ESA
distant-traveller:

Carbon worlds may be waterless, finds NASA study

Planets rich in carbon, including so-called diamond planets, may lack oceans, according to NASA-funded theoretical research. Our sun is a carbon-poor star, and as result, our planet Earth is made up largely of silicates, not carbon. Stars with much more carbon than the sun, on the other hand, are predicted to make planets chock full of carbon, and perhaps even layers of diamond.
By modeling the ingredients in these carbon-based planetary systems, the scientists determined they lack icy water reservoirs thought to supply planets with oceans.
The building blocks that went into making our oceans are the icy asteroids and comets. If we keep track of these building blocks, we find that planets around carbon-rich stars come up dry. The team says that the extra carbon in developing star systems would snag the oxygen, preventing it from forming water. 
"It’s ironic that if carbon, the main element of life, becomes too abundant, it will steal away the oxygen that would have made water, the solvent essential to life as we know it," said Jonathan Lunine of Cornell University, Ithaca, N.Y., a collaborator on the research.

Image credit: NASA/JPL-Caltech
phototoartguy:

Wonderful Photo Shows Police Stopped NYC Traffic For A Cat And Her Kitten In 1925
gravitationalbeauty:

NGC 1309 and Friends
spacettf:

"Little Iris" LBN408 in Cygnus by Oleg Bryzgalov on Flickr.