From NASA of Space...

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NGC 604 is a H II region inside the Triangulam Galaxy. It was discovered by William Harschel on 11th Sep,1784. It is one of the largest H II regions in the Local Group of galaxies estimated distance of 2.7 million light-years it's longest diameter is roughly 1500 light-years(460 parsecs) over 40 times the size of the visible portion of the Orion Nebula. It is over 6300 times mo

re luminous than the Orion Nebula and if it were at the same distance it would out shine Venus Like all emission nebulae it's gas is ionized by a cluster of Massive stars at it's center.

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This clock representation shows some of the major units of geological time and definitive events of Earth history, The Hadean eon represents the time before fossil record of life on Earth, its upper boundary is now considered as 4.0Ga. Other sub-divisions reflect the evolu

tion of life. The Archean and Proterozoic are both eons, The Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon the two million years Quaternary period. The time of recognizable humans is too small to be visible at this scale.

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image credit: NASA,EST,HST, Andrew Fruchter,(STScI)and the ERO team(STScI+ST-ECF)_

NGC 2392 lies more than 2870 light year away and visible in the Constellation of Gemini._

The Eskimo Nebula(NGC 2392) ,also know as the Clownface Nebula or Caldwell 39, is a bipokar double-Shell planetary nebula. In 1787,William Harschel discovered it.
The formation resembles a person's head surrounded by a Parka hood. It is surrounded by gas that composed the other layers of a Sun-like star._

The visible inner filaments are ejected by a strong wind of particles from the central star, The outer disk,contains unusual light year long orange filaments.

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The Keplar spacecraft is in a Heliocentric Orbit, 

so that Earth does not occult the stars which are observed continuously, and so the photometer is not influenced by stray light from Earth. This orbit avoids the gravitational perturbations and Torques inhernt in an Earth orbit, allowing for a more stable viewing platfrom.

The photometer points to a field in the Northern constellations of Cygnus, Lyra and Draco(image), which is well out of the ecliptic plane. So sunlight never enters the photometer as the spacecraft orbits the Sun,Cygnus is also a good choice to observe because it'll never be obscured by asteroid belt.
other benefit is that Keplar is pointing in the direction of the Solar system's motion around the center of the galaxy. Thus the stars which are observed by Keplar are roughly the same distance from the glactic center as the solar system and also close to the galactic plane. its important if position in the Galaxy is related to habitability as suggested by the Rare Earth hypothesis____

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Exp:what does a Coment nucleus look like?

Formed from the priomordial stuff of the solar system.It's thought to resemble a very dirty iceberg.But for active comets,telescopic images only reveal the surrounding cloud of gas n dust, the comet's coma n the characteristic cometary tails.In 1986 The ESA's Giotto encountered the necleus of Halley's comet as it approached the Sun.Data from Giotto Camera was used to generate this enhanced image of the potato shaped nucleus which measured roughly 15km across,It shows surface features on the dark nucleus against the bright background of the coma as the icy material is Vaporized by the sun's heat,Every 76yrs Halley returns to the inner solar system n each time the nucleus sheds about a 6 meter deep layer of its ice n rock into space.This debris composes Halley's tails n leaves an orbiting trail responsible for the Orionids meteor shower

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NEWS From "NASA"

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This Is the First Picture Ever Taken From Space—and It Was Taken From a Nazi Rocket

This grainy picture was taken on October 24, 1946, almost 14 months after the end of World War II and almost 11 years before the Sputnik launch. It was taken by American military engineers and scientists, using a Nazi rocket launched from the White Sands Missile Range, in New Mexico.

Yes, a Nazi rocket—the V-2.

At the time there was no NASA, and human space exploration wasn't a mainstream idea. The only people who were really thinking about spaceships at the time were the Nazis of a few years earlier and their spitzenreiter mad rocket science, a man by the name of Wernher Magnus Maximilian, Freiherr von Braun.

Von Braun dreamed about spaceships and wanted to build rockets at all cost, so he became a member of the Allgemeine SS and the Nazi Party. It was then that Hitler gave him the money, material and slave labor to built the V-2, the rocket bomb that terrorized London at the end of the WWII, morals be damned.

But by 1946, von Braun had become an American rocket scientist. And the Americans had a bunch of V-2s, having seized the ones that weren't launched or were under construction when the Allies captured their launch and factory sites at the end of the war. They were imported to the United States, along with Von Braun.

Von Braun and the Americans kept working on these and other missile designs while launching the existing V-2s into space for testing. One of the engineers, Clyde Holliday, had developed a 35mm camera that took a photo every second and a half. None of the other scientists and engineers cared much about photography. They only wanted information about cosmic rays and aerodynamic performance.

Holiday understood even then that images were going to be the most powerful application of space rockets. He was right. Not only did space photography become instrumental in our understanding of Earth, its surface and its weather systems—hello frankenstorm Sandy—but it did something even more important: make humanity realize where, and how small, we are.

In 1950, National Geographic showed these photos to the world for the first time, and Holliday wrote that this is "how our Earth would look to visitors from another planet coming in on a space ship."

I'm sure that everyone who saw them instantly had the impulse to jump in a rocket and go see it themselves first-hand. I know I still do.

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Glass beads within moon rocks suggest that water seen on the lunar surface originates from the solar wind, researchers say.

These findings suggest that other airless bodies in the solar system may also possess water on their surfaces, investigators added.

Arguments raged for years as to whether the moon harbored frozen water or not. Recent findings confirmed that water does wet the moon, although its surface remains drier than any desert on Earth.

"With the cost of $25,000 for taking one pint of water to the moon, it is essential that we develop processes of producing water from the materials on the moon," said the study's lead author, Yang Liu, at the University of Tennessee at Knoxville. "This is paramount to human settlement of the moon in the near future." [Gallery: Our Changing Moon]

"This water would be of most value as rocket fuel — liquid hydrogen and liquid oxygen," Liu added. "Until the recent discovery of water in and on the moon, this was going to be a very energy-intensive endeavor to separate these elements from the lunar rocks and soil. Now we have ready sources of water that can be consumed by plants and humans, but also broken up into its constituent elements — oxygen and hydrogen. Thus, we could use the moon as a jump-board for missions to Mars and beyond."

It remained uncertain where all of this water might come from, although some apparently came from ice-rich comets. To find out more, scientists analyzed lunar surface dust, or regolith, that astronauts on the Apollo missions brought from the moon.Most samples actually come from an Apollo 11 soil collected by Neil Armstrong," Liu told SPACE.com.

Lunar regolith is created by meteoroids and charged particles constantly bombarding lunar rock. The researchers focused on grains of glass in the samples that were created in the heat of countless micrometeoroid impacts on the moon. They reasoned this glass might have captured any water in the regolith before it cooled and solidified.

The investigators found that a large percentage of this glass contained traces of wetness — between 200 and 300 parts per million of water and the molecule hydroxyl, which is much like water, save that each of its molecules possesses just one hydrogen atom, not two.

To figure out where this water and hydroxyl originated from, the scientists looked at their hydrogen components. Hydrogen atoms come in a variety of isotopes, each with a different number of neutrons in their nuclei — regular hydrogen has no neutrons, while the isotope known as deuterium has one in each atomic nucleus.

The sun is naturally low in deuterium because its nuclear activity rapidly consumes the isotope. All other objects in the solar system possess relatively high levels of it, remnants of deuterium that existed in the nebula of gas and dust that gave birth to the solar system.

The researchers found that the water and hydroxyl seen in the lunar glass were both low in deuterium. This suggests their hydrogen came from the sun, probably blasted onto the moon via winds of charged particles from the sun, which continuously streams from the sun at a rate of 2.2 billion pounds (1 billion kilograms) per second. The moon, lacking a significant atmosphere or magnetic field, slowly captures all the particles striking it. The hydrogen particles then bonded with oxygen bound in rocks on the lunar surface.

"The origin of surface water on the moon was unclear," Liu said. "We provide robust evidence for a solar wind origin. This finding emphasizes the potential in finding such water on the surface of other similar airless bodies, such as Eros, Deimos, Vesta."

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A highly-elliptical crater chain on Mars was likely formed as an impacting space rock came down nearly parallel to the surface.

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This image covers an impact crater on the northeast rim of Hellas basin, with excellent exposures of bedrock layers.
Here we see a portion of the steep inner slope where some of the bedrock has broken into angular pieces and slide partway down the slope.

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From NASA

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NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This colorful portrait of the nebula uses narrow band image data combined in the Hubble palette. It shows emission from sulfur, hydrogen, and oxygen atoms in the wind-blown nebula in red, green and blue hues. NGC 6888's 

central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away.

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There is something very unusual in this picture of the Earth -- can you find it? A fleeting phenomenon once thought to be only a legend has been newly caught if you know just where to look. The above image was taken from the orbiting International Space Station (ISS) in late April and shows familiar ISS solar panels on the far left and part of a robotic arm to the 

far right. The rarely imaged phenomenon is known as a red sprite and it can be seen, albeit faintly, just over the bright area on the image right. This bright area and the red sprite are different types of lightning, with the white flash the more typical type. Although sprites have been reported anecdotally for as long as 300 years, they were first caught on film in 1989 -- by accident. Much remains unknown about sprites including how they occur, their effect on the atmospheric global electric circuit, and if they are somehow related to other upper atmospheric lightning phenomena such as blue jets or terrestrial gamma flashes. 

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A rare and spectacular head-on collision between two galaxies appears in this Hubble telescope picture of the Cartwheel Galaxy, located 500 million light-years from Earth in the constellation Sculptor. 

The striking ring-like feature is a direct result of a smaller intruder galaxy — possibly one of two objects to the right of the ring — that careened through the core [close-up i

mage at lower left] of the host galaxy. Like a rock tossed into a lake, the collision sent a ripple of energy into space, plowing gas and dust in front of it. Expanding at 200,000 mph, this cosmic tsunami leaves in its wake a firestorm of new star creation. Hubble resolves bright blue knots that are gigantic clusters of newborn stars [close-up image at upper left] and immense loops and bubbles blown into space by exploding stars (called supernovae) going off like a string of firecrackers.

The Cartwheel Galaxy (also known as ESO 350-40) is a lenticular galaxy about 500 million light-years away in the constellation Sculptor. It is an estimated 150,000 light-years across, has a mass of about 2.9–4.8 × 109 solar masses, and rotates at 217 km/s.

It was discovered by Fritz Zwicky in 1941. Zwicky considered his discovery to be "one of the most complicated structures awaiting its explanation on the basis of stellar dynamics."

An estimation of the galaxy's span resulted in a conclusion of 150,000 light years, which is slightly larger than the Milky Way.

Evolution

The galaxy was once a normal spiral galaxy before it apparently underwent a head-on collision with a smaller companion approximately 200 million years ago (i.e., 200 million years prior to the image) When the nearby galaxy passed through the Cartwheel Galaxy, the force of the collision caused a powerful shock wave through the galaxy, like a rock being tossed into a sandbed. Moving at high speed, the shock wave swept up gas and dust, creating a starburst around the galaxy's center portion that were unscathed. This explains the bluish ring around the center, brighter portion.[9] It can be seen that the galaxy is beginning to retake the form of a normal spiral galaxy, with arms spreading out from a central core.

Alternatively, a model based on the gravitational Jeans instability of both axisymmetric (radial) and nonaxisymmetric (spiral) small-amplitude gravity perturbations allows an association between growing clumps of matter and the gravitationally unstable axisymmetric and nonaxisymmetric waves which take on the appearance of a ring and spokes.

X-ray sources

The unusual shape of the Cartwheel Galaxy may be due to a collision with a smaller galaxy such as those in the lower left of the image. The most recent star burst (star formation due to compression waves) has lit up the Cartwheel rim, which has a diameter larger than the Milky Way. Star formation via starburst galaxies, such as the Cartwheel Galaxy, results in the formation of large and extremely luminous stars. When massive stars explode as supernovas, they leave behind neutron stars and black holes. Some of these neutron stars and black holes have nearby companion stars, and become powerful sources of X-rays as they pull matter off their companions. The brightest X-ray sources are likely black holes with companion stars, and appear as the white dots that lie along the rim of the X-ray image. The Cartwheel contains an exceptionally large number of these black hole binary X-ray sources, because many massive stars formed in the rim.

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News of space From NASA

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Reflection Nebula vdB1
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, University of Arizona
Explanation: Every book has a firstpage and every catalog a first entry. And so this lovely blue cosmic cloud begins the van den Bergh Catalog (vdB) of stars surrounded by reflection nebulae. Interstellar dust clouds reflecting the light of the nearby stars, the nebulae usually appear blue beca

use scattering by the dust grains is more effective at shorter (bluer) wavelengths. The same type of scattering gives planet Earth its blue daytime skies. Van den Bergh's 1966 list contains a total of 158 entries more easily visible from the northern hemisphere, including bright Pleiades cluster stars and other popular targets for astroimagers. Less than 5 light-years across, VdB1 lies about 1,600 light-years distant in the constellation Cassiopeia. Also on this scene, twointriguing nebulae at the right show loops and outflow features associated with the energetic process of star formation. Within are extremely young variable starsV633 Cas (top) and V376 Cas.

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NASA's Curiosity rover mission has found evidence a stream once ran vigorously across the area on Mars where the rover is driving. There is earlier evidence for the presence of water on Mars, but this evidence -- images of rocks containing ancient streambed gravels -- is the first of its kind.

Scientists are studying the images of stones cemented into a layer of conglomerate rock. The sizes and s

hapes of stones offer clues to the speed and distance of a long-ago stream's flow.

"From the size of gravels it carried, we can interpret the water was moving about 3 feet per second, with a depth somewhere between ankle and hip deep," said Curiosity science co-investigator William Dietrich of the University of California, Berkeley. "Plenty of papers have been written about channels on Mars with many different hypotheses about the flows in them. This is the first time we're actually seeing water-transported gravel on Mars. This is a transition from speculation about the size of streambed material to direct observation of it."

The finding site lies between the north rim of Gale Crater and the base of Mount Sharp, a mountain inside the crater. Earlier imaging of the region from Mars orbit allows for additional interpretation of the gravel-bearing conglomerate. The imagery shows an alluvial fan of material washed down from the rim, streaked by many apparent channels, sitting uphill of the new finds.

The rounded shape of some stones in the conglomerate indicates long-distance transport from above the rim, where a channel named Peace Vallis feeds into the alluvial fan. The abundance of channels in the fan between the rim and conglomerate suggests flows continued or repeated over a long time, not just once or for a few years.

The discovery comes from examining two outcrops, called "Hottah" and "Link," with the telephoto capability of Curiosity's mast camera during the first 40 days after landing. Those observations followed up on earlier hints from another outcrop, which was exposed by thruster exhaust as Curiosity, the Mars Science Laboratory Project's rover, touched down.

"Hottah looks like someone jack-hammered up a slab of city sidewalk, but it's really a tilted block of an ancient streambed," said Mars Science Laboratory Project Scientist John Grotzinger of the California Institute of Technology in Pasadena.

The gravels in conglomerates at both outcrops range in size from a grain of sand to a golf ball. Some are angular, but many are rounded.

"The shapes tell you they were transported and the sizes tell you they couldn't be transported by wind. They were transported by water flow," said Curiosity science co-investigator Rebecca Williams of the Planetary Science Institute in Tucson, Ariz.

The science team may use Curiosity to learn the elemental composition of the material, which holds the conglomerate together, revealing more characteristics of the wet environment that formed these deposits. The stones in the conglomerate provide a sampling from above the crater rim, so the team may also examine several of them to learn about broader regional geology.

The slope of Mount Sharp in Gale Crater remains the rover's main destination. Clay and sulfate minerals detected there from orbit can be good preservers of carbon-based organic chemicals that are potential ingredients for life.

"A long-flowing stream can be a habitable environment," said Grotzinger. "It is not our top choice as an environment for preservation of organics, though. We're still going to Mount Sharp, but this is insurance that we have already found our first potentially habitable environment."

During the two-year prime mission of the Mars Science Laboratory, researchers will use Curiosity's 10 instruments to investigate whether areas in Gale Crater have ever offered environmental conditions favorable for microbial life.

NASA's Jet Propulsion Laboratory, a division of Caltech, built Curiosity and manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington.

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A Surprisingly Bright Superbubble
This composite image shows a superbubble in the Large Magellanic Cloud (LMC), a small satellite galaxy of the Milky Way located about 160,000 light years from Earth. Many new stars, some of them very massive, are forming in the star cluster NGC 1929, which is embedded in the nebula N44, so named because it is the 44th nebula in a catalog of such objects in the Mag

ellanic Clouds. The massive stars produce intense radiation, expel matter at high speeds, and race through their evolution to explode as supernovas. The winds and supernova shock waves carve out huge cavities called superbubbles in the surrounding gas. X-rays from NASA's Chandra X-ray Observatory (blue) show hot regions created by these winds and shocks, while infrared data from NASA's Spitzer Space Telescope (red) outline where the dust and cooler gas are found. The optical light from the 2.2-m Max-Planck-ESO telescope (yellow) in Chile shows where ultraviolet radiation from hot, young stars is causing gas in the nebula to glow.

A long-running problem in high-energy astrophysics has been that some superbubbles in the LMC, including N44, give off a lot more X-rays than expected from models of their structure. These models assume that hot, X-ray emitting gas has been produced by winds from massive stars and the remains of several supernovas. A Chandra study published in 2011 showed that there are two extra sources of N44’s X-ray emission not included in these models: supernova shock waves striking the walls of the cavities, and hot material evaporating from the cavity walls. The Chandra observations also show no evidence for an enhancement of elements heavier than hydrogen and helium in the cavities, thus ruling out this possibility as a third explanation for the bright X-ray emission. Only with long observations making full use of the capabilities of Chandra has it now become possible to distinguish between different sources of the X-rays produced by superbubbles. 

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This artist concept features NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or present ability to sustain microbial life. 

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Impossible...

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LIVING ON THE EDG
Photograph by Tim Kemple
The person sitting on that ledge is Alex Honnold. He’s been proclaimed the best free soloist (i.e., climbs without ropes) in the world. The startling image above (posted to Reddit and tracked down to photographer Tim Kemple) shows Mr. Honnold midway up Half Dome, an incredibly challenging granite dome in Yosemite National Park 4,737 ft (1,444 m) above the valley floor.

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THE CHICAGO SKYLINE FROM INDIANA

Photograph by Tom Adams on Reddit

This incredible photograph of the Chicago skyline by photographer Tom Adams was number one on the front page of Reddit a couple days ago. The striking view was captured from a beach in Porter, Indiana (approx. 1 hour drive from Chicago).

The body of water in the foreground is Lake Michigan and Tom took this photograph using a Canon 60D with a medium telephoto lens. He made a slight adjustment to the exposure in Lightroom.

The setting sun adds an incredible richness and colour to this photograph and it’s certainly one of the most beautiful the Sifter has seen in recent time. Full kudos to Mr. Adams on a truly stunning capture. 

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Welcome back to Holland!

Camera Canon EOS 1000D

Focal Length 18mm

Shutter Speed 1/6 sec

Aperture f/10

ISO/Film 200

Photo Credit: Jurjen Harmsma

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Different type of Flowers.

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Astronomy

• The speed of sound is 343.2 metres per second (1,126 ft/s). This is 1,236 kilometres per hour (768 mph), or about one kilometer in three seconds or approximately one mile in five seconds. Felix got to 1,342.8 km per hour.

He says the most beautiful moment was the few seconds when he was on top of the world looking down

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During the past few nights of storming, auroras with rare pulsations, colors, and shapes have been sighted all around the Arctic Circle. In Lofoten, Norway, the lights formed an exquisite green butterfly:
If this picture confuses you, turn it sideways to see it the same way photographer June Grønseth did. "I took more than 400 pictures last night," says Grønseth. "The butterfly and the heart were my favorites." 

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The storm - the largest in five years - will unleash a torrent of charged particles between 06:00 GMT and 10:00 GMT, US weather specialists say.

They say it was triggered by a pair of massive solar flares earlier this week.

It means there is a good chance of seeing the northern lights at lower latitudes, if the skies are clear.

The effects will be most intense in polar regions, and aircraft may be advised to change their routings to avoid these areas.

In the UK, the best chance to see them will be on Thursday night, the British Geological Survey says.

The charged particles are expected to hit Earth at 4,000,000 mph (6,400,000 km/h), and Noaa predicts the storm will last until Friday morning.

Images of the Sun's region where the flares happened show a complex network of sunspots indicating a large amount of stored magnetic energy.

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News about Space...

• Saturn's Moon Titan Has Soft and Crusty Surface, Probe Landing Reveals

This image is an artist's impression of the descent and landing sequence followed by ESA's Huygens probe that landed on Titan. The Jan. 14, 2005 landing was the culmination of a 22-year process of planning, organizing and cooperation between ESA and NASA.

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When Galaxies Eat Galaxies: Gravity Lenses Suggest Big Collisions Make Galaxies Denser

This image, taken by the Hubble Space Telescope, shows a ring of light from a distant galaxy created when a closer galaxy in the foreground – not shown in this processed image – acts as a “gravitational lens” to bend the light from the more distant galaxy into the ring of

 light, known as an Einstein ring. In a new study, University of Utah astronomer Adam Bolton and colleagues measured these Einstein rings to determine the mass of 79 lens galaxies that are massive elliptical galaxies, the largest kind of galaxy with 100 billion stars. The study found the centers of these big galaxies are getting denser over time, evidence of repeated collisions between massive galaxies. (Credit: Joel Brownstein, University of Utah, for NASA/ESA and the Sloan Digital Sky Survey)

(Oct. 12, 2012) — Using gravitational "lenses" in space, University of Utah astronomers discovered that the centers of the biggest galaxies are growing denser -- evidence of repeated collisions and mergers by massive galaxies with 100 billion stars.


"We found that during the last 6 billion years, the matter that makes up massive elliptical galaxies is getting more concentrated toward the centers of those galaxies. This is evidence that big galaxies are crashing into other big galaxies to make even bigger galaxies," says astronomer Adam Bolton, principal author of the new study.

"Most recent studies have indicated that these massive galaxies primarily grow by eating lots of smaller galaxies," he adds. "We're suggesting that major collisions between massive galaxies are just as important as those many small snacks."

The new study -- published recently in The Astrophysical Journal -- was conducted by Bolton's team from the Sloan Digital Sky Survey-III using the survey's 2.5-meter optical telescope at Apache Point, N.M., and the Earth-orbiting Hubble Space Telescope.

The telescopes were used to observe and analyze 79 "gravitational lenses," which are galaxies between Earth and more distant galaxies. A lens galaxy's gravity bends light from a more distant galaxy, creating a ring or partial ring of light around the lens galaxy.

The size of the ring was used to determine the mass of each lens galaxy, and the speed of stars was used to calculate the concentration of mass in each lens galaxy.

Bolton conducted the study with three other University of Utah astronomers -- postdoctoral researcher Joel Brownstein, graduate student Yiping Shu and undergraduate Ryan Arneson -- and with these members of the Sloan Digital Sky Survey: Christopher Kochanek, Ohio State University; David Schlegel, Lawrence Berkeley National Laboratory; Daniel Eisenstein, Harvard-Smithsonian Center for Astrophysics; David Wake, Yale University; Natalia Connolly, Hamilton College, Clinton, N.Y.; Claudia Maraston, University of Portsmouth, U.K.; and Benjamin Weaver, New York University.

Big Meals and Snacks for Massive Elliptical Galaxies

The new study deals with the biggest, most massive kind of galaxies, known as massive elliptical galaxies, which each contain about 100 billion stars. Counting unseen "dark matter," they contain the mass of 1 trillion stars like our sun.

"They are the end products of all the collisions and mergers of previous generations of galaxies," perhaps hundreds of collisions," Bolton says.

Despite recent evidence from other studies that massive elliptical galaxies grow by eating much smaller galaxies, Bolton's previous computer simulations showed that collisions between large galaxies are the only galaxy mergers that lead, over time, to increased mass density on the center of massive elliptical galaxies.

When a small galaxy merges with a larger one, the pattern is different. The smaller galaxy is ripped apart by gravity from the larger galaxy. Stars from the smaller galaxy remain near the outskirts -- not the center -- of the larger galaxy.

"But if you have two roughly comparable galaxies and they are on a collision course, each one penetrates more toward the center of the other, so more mass ends up in the center," Bolton says.

Other recent studies indicate stars are spread more widely within galaxies over time, supporting the idea that massive galaxies snack on much smaller ones.

"We're finding galaxies are getting more concentrated in their mass over time even though they are getting less concentrated in the light they emit," Bolton says.

He believes large galaxy collisions explain the growing mass concentration, while galaxies gobbling smaller galaxies explain more starlight away from galactic centers.

"Both processes are important to explain the overall picture," Bolton says. "The way the starlight evolves cannot be explained by the big collisions, so we really need both kinds of collisions, major and minor -- a few big ones and a lot of small ones."

The new study also suggests the collisions between large galaxies are "dry collisions" -- meaning the colliding galaxies lack large amounts of gas because most of the gas already has congealed to form stars -- and that the colliding galaxies hit each other "off axis" or with what Bolton calls "glancing blows" rather than head-on.

Sloan Meets Hubble: How the Study Was Conducted

The University of Utah joined the third phase of the Sloan Digital Sky Survey, known as SDSS-III, in 2008. It involves about 20 research institutions around the world. The project, which continues until 2014, is a major international effort to map the heavens as a way to search for giant planets in other solar systems, study the origin of galaxies and expansion of the universe, and probe the mysterious dark matter and dark energy that make up most of the universe.

Bolton says his new study was "almost gravy" that accompanied an SDSS-III project named BOSS, for Baryon Oscillation Spectrographic Survey. BOSS is measuring the history of the universe's expansion with unprecedented precision. That allows scientists to study the dark energy that accelerates expansion of the universe. The universe is believed to be made of only 4 percent regular matter, 24 percent unseen "dark matter" and 72 percent yet-unexplained dark energy.

During BOSS' study of galaxies, computer analysis of light spectra emitted by galaxies revealed dozens of gravitational lenses, which were discovered because the signatures of two different galaxies are lined up.

Bolton's new study involved 79 gravitational lenses observed by two surveys:

- The Sloan Survey and the Hubble Space Telescope collected images and emitted-light color spectra from relatively nearby, older galaxies -- including 57 gravitational lenses -- 1 billion to 3 billion years back into the cosmic past.

- Another survey identified 22 lenses among more distant, younger galaxies from 4 billion to 6 billion years in the past.

The rings of light around gravitational-lens galaxies are named "Einstein rings" because Albert Einstein predicted the effect, although he wasn't the first to do so.

"The more distant galaxy sends out diverging light rays, but those that pass near the closer galaxy get bent into converging light rays that appear to us as of a ring of light around the closer galaxy," says Bolton.

The greater the amount of matter in a lens galaxy, the bigger the ring. That seems counterintuitive, but the larger mass pulls with enough gravity to make the distant star's light bend so much that lines of light cross as seen by the observer, creating a bigger ring.

If there is more matter concentrated near the center of a galaxy, the faster stars will be seen moving toward or being slung away from the galactic center, Bolton says.

Alternative Theories

Bolton and colleagues acknowledge their observations might be explained by theories other than the idea that galaxies are getting denser in their centers over time:

- Gas that is collapsing to form stars can increase the concentration of mass in a galaxy. Bolton argues the stars in these galaxies are too old for that explanation to work.

- Gravity from the largest massive galaxies strips neighboring "satellite" galaxies of their outskirts, leaving more mass concentrated in the centers of the satellite galaxies. Bolton contends that process is not likely to produce the concentration of mass observed in the new study and explain how the extent of that central mass increases over time.

- The researchers merely detected the boundary in each galaxy between the star-dominated inner regions and the outer regions, which are dominated by unseen dark matter. Under this hypothesis, the appearance of growing galaxy mass concentration over time is due to a coincidence in researchers' measurement method, namely that they are measuring younger galaxies farther from their centers and measuring older galaxies closer to their centers, giving an illusion of growing mass concentration in galactic centers over time. Bolton says this measurement difference is too minor to explain the observed pattern of matter density within the lens galaxies.

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(Oct. 11, 2012) — ESA's Huygens probe bounced, slid and wobbled its way to rest in the 10 seconds after touching down on Saturn's moon, Titan, in January 2005, a new analysis reveals. The findings provide novel insight into the nature of the moon's surface.


Scientists reconstructed the chain of events by analysing data from a variety of instruments that were active during the impact, in particular changes in the acceleration experienced by the probe.

The instrument data were compared with results from computer simulations and a drop test using a model of Huygens designed to replicate the landing.

The analysis reveals that, on first contact with Titan's surface, Huygens dug a hole 12 cm deep, before bouncing out onto a flat surface.

The probe, tilted by about 10 degrees in the direction of motion, then slid 30-40 cm across the surface.

It slowed due to friction with the surface and, upon coming to its final resting place, wobbled back and forth five times, with each wobble about half as large as the previous one.

Huygens' sensors continued to detect small vibrations for another two seconds, until motion subsided nearly 10 seconds after touchdown.

"A spike in the acceleration data suggests that during the first wobble, the probe likely encountered a pebble protruding by around 2 cm from the surface of Titan, and may have even pushed it into the ground, suggesting that the surface had a consistency of soft, damp sand," describes Dr Stefan Schröder of the Max Planck Institute for Solar System Research, lead author of the paper reporting the results in Planetary and Space Science.

Had the probe impacted a wet, mud-like substance, its instruments would have recorded a 'splat' with no further indication of bouncing or sliding.

The surface must have therefore been soft enough to allow the probe to make a hole, but hard enough to support Huygens rocking back and forth.

"We also see in the Huygens landing data evidence of a 'fluffy' dust-like material -- most likely organic aerosols that are known to drizzle out of the Titan atmosphere -- being thrown up and suspended for around four seconds after the impact," says Dr Schröder.

Since the dust was easily lifted, it was most likely dry, suggesting that there had not been any 'rain' of liquid ethane or methane for some time prior to the landing.

"This study takes us back to the historical moment of Huygens touching down on the most remote alien world ever visited by a landing probe," adds ESA's Cassini-Huygens project scientist, Nicolas Altobelli.

"Huygens data, even years after mission completion, are providing us with a new dynamical 'feeling' for these crucial first seconds of landing."

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Pioneer Anomaly Solved? Interstellar Travelers of the Future May Be Helped by Physicist's Calculations

An artist's view of a Pioneer spacecraft heading into interstellar space. Both Pioneer 10 and 11 are on trajectories that will eventually take them out of our solar system. (Credit: NASA)

Oct. 9, 2012) — Interstellar travel will depend upon extremely precise measurements of every factor involve

d in the mission. The knowledge of those factors may be improved by the solution a University of Missouri researcher found to a puzzle that has stumped astrophysicists for decades.

"The Pioneer spacecraft, two probes launched into space in the early 70s, seemed to violate the Newtonian law of gravity by decelerating anomalously as they traveled, but there was nothing in physics to explain why this happened," said Sergei Kopeikin, professor of physics and astronomy in MU's College of Arts and Science. "My study suggests that this so-called Pioneer anomaly was not anything strange. The confusion can be explained by the effect of the expansion of the universe on the movement of photons that make up light and radio waves."

Beams of radio waves were sent to and bounced off the Pioneer spacecraft to measure the probes' movement. The time it took for the photons to complete a round trip was used to calculate the spacecrafts' distance and speed. Kopeikin's research suggests that the photons move faster than expected from the Newtonian theory thus causing the appearance of deceleration, though the craft were actually traveling at the correct speed predicted by the theory. The universe is constantly expanding and this alters the Earth-based observations of the photons bouncing off the spacecraft, causing the Pioneer probes to appear to slow down.

"Previous research has focused on mechanical explanations for the Pioneer anomaly, such as the recoil of heat from the craft's electrical generators pushing the craft backwards," Kopeikin said. "However that only explains 15 to 20 percent of the observed deceleration, whereas it is the equation for photons that explains the remaining 80-85 percent."

Physicists must be careful when dealing with propagation of light in the presence of the expansion of space, noted Kopeikin, since it is affected by forces that are irrelevant in other equations. For example, the expansion of the universe affects photons, but doesn't influence the motion of planets and electrons in atoms.

"Having accurate measurements of the physical parameters of the universe help us form a basis to make plans for interstellar exploration," Kopeikin said. "Discerning the effect of the expansion of the universe on light is important to the fundamental understanding of space and time. The present study is part of a larger on-going research project that may influence the future of physics."

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