Nobel For The Universe

The stars that we see in the night sky, speaks to us. Each star tries to tell a story of their lifetime. But it was our inability that we were unable hear or understand their words until the year 1998, when the first space telescope i.e,. the Hubble Space Telescope was installed. It was the HST that showed us that the Universe is much more complex than we thought. The complexity arises from a theory which physicist used to follow for decades. This theory is the Einstein's  Theory of Gravitation. According to this theory the rate of expansion of the Universe must slow down with time. But the study of the various distant supernova explosions showed that the rate of expansion of the Universe at that time was much slower than today. With the advent of this surprising observation doubts on Einstein's Theory of Gravitation started to arise. But then Saul Perlmutter, Brain P. Schmidt and Adam G. Riess after studying the red shifts of different supernovas concluded that there was nothing wrong in the Theory of Gravitation. Wrong was in our Observation.

The Red shifts or the accelerated expansion of the Universe was due to the presence of an unknown, or undetectable presence of energy that is acting strongly against the gravitation due to the presence of  5% of matter in the Universe. This invisible form of Energy is termed as "Dark Energy".  

Jupiter as seen on Aug 20th 2011

For 3 weeks i have been waiting for a clear night sky, to observe Jupiter, which rises in the east these days at 22:00 hrs. By 02:00 hrs it reaches near zenith (just above head). Today i got the opportunity to observe this beautiful planet with my naked eye.I observed this planet just below the Moon at 01:21 hrs. I captured it by my 2 mega pixel mobile camera (nokia 5233). I made some adjustments like increasing the exposure and also increasing the ISO. Increasing the exposure enabled the camera to receive maximum amount of light from jupiter and the moon. The blackish white dot inside the red circle in the picture above is the jupiter as captured by my camera. I have also shared all the snaps (look at the slideshow above). Please give me feedback for this post. Tell me "How did you like it?".

Thanking You,

Prithish Halder

Dawn SpEcraft Captures Up-Close Imagery of Asteroid Vesta

The Dawn spacecraft is sending back some of the first full-frame images of the asteroid Vesta as it spirals towards the first of four science orbits around the asteroid.

The images, which were captured on July 24, were taken at a distance of 3,200 miles from Vesta and reveal some of the first surface details about the asteroid. They cover the entire asteroid, NASA said, because Vesta turns on its axis once every five hours and 20 minutes.

"Now that we are in orbit around one of the last unexplored worlds in the inner solar system, we can see that it's a unique and fascinating place," Marc Rayman, Dawn's chief engineer and mission manager at NASA's Jet Propulsion Laboratory, said in a statement.

The images were collected via Dawn's framing camera, but the spacecraft also includes a gamma ray and neutron detector, which uses 21 sensors to measure the energy of subatomic particles emitted by Vesta. An infrared mapping spectrometer will also measure the surface mineralogy of Vesta and Dawn's next target, the dwarf planet Ceres.
That first intensive science orbit, meanwhile, will begin August 11 at an altitude of 1,700 miles and provide in-depth analysis of Vesta.

"We have been calling Vesta the smallest terrestrial planet," said Chris Russell, Dawn's principal investigator at UCLA. "The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta's planetary aspirations."

Dawn successfully entered Vesta's orbit on July 16, and sent back the first images several days later. Engineers are still trying to determine the exact time Dawn entered Vesta's orbit, but are currently estimating it at 12:47am Eastern time.

Dawn will study Vesta for one year, gathering observations that NASA said will help scientists understand the earliest chapter of our solar system's history. Dawn will then depart for the dwarf planet Ceres in July 2012.

This milestone has been several years in the making; Dawn departed Earth in 2007 and when it completes its journey, it will become the first spacecraft to orbit two solar system destinations beyond Earth, NASA said.

SOHO Watches a Comet Fading Away

On Nov. 4, 2010, NASA’s EPOXI spacecraft came within 450 miles of Comet Hartley 2, a small comet not even a mile in diameter, which takes about six and a half years to orbit the sun. Designated officially as 103P/Hartley 2, the comet thus became the fifth for which scientists have collected close-up images.

But the comet was also observed from another spacecraft: the Solar and Heliospheric Observer (SOHO), better known for its observations of the sun. Together, the two returned data about what appears to be an irregular comet, belching chunks of ice and losing water at a surprisingly fast pace.


“By combining EPOXI’s direct imaging with several months of SOHO data, we had a rare chance to see a comet in the process of shedding off large amounts of water,” says Michael Combi, a space scientist at the University of Michigan in Ann Arbor, Mich., who wrote about his findings in a June 10, 2011 issue of the Astrophysical Journal Letters. “Comets always lose water as they heat up during the approach to the sun, but this was much more than usual. Something pretty dramatic happened in those weeks.”

Understanding the composition and behavior of comets intrigues scientists because they are some of the first objects that formed around our sun some 4.5 billion years ago and they’ve evolved little since. These chunks of ice, rock, and frozen gas hold clues to what existed in those early days of the solar system’s formation, says Combi. So he uses an instrument onboard SOHO called SWAN – for Solar Wind ANistropy – to observe how water streams off of comets.

SWAN’s main job is to map the distribution of hydrogen atoms across the entire sky. This helps those who study the sun’s magnetic environment by tracking how the interstellar wind of particles moves through our area of space. But the instrument also can help track comets, which are generally surrounded by an extremely thin atmosphere of water vapor. Under ultraviolet light from the sun, the hydrogen atoms fly off the water molecules at great speed and produce a huge cloud or “coma” of hydrogen. The coma absorbs sunlight and then re-emits it, making it detectable in SWAN images. Observing the clouds can then help determine how much water is being vaporized from the comet over time.

SWAN has collected data on nearly one hundred comets, so when Combi and his colleagues at Michigan learned EPOXI was destined to get a closer view of Hartley 2, they pored over old data from that comet’s most recent approaches in 1997 and 2004. Unfortunately, the sun obscured SOHO’s view of Hartley in 2004, but the 1997 data was accessible. They compared this to SWAN’s 2010 observations from Sept. 14 to Dec. 15.

Surprisingly, the comet’s water production in 1997 was three times the amount of water put out in 2010. “We’ve analyzed multiple comets with short periods like Hartley 2 on repeated trips around the sun,” says Combi. “But none of them has shown such a drastic change from one close pass by the sun to the next.”

The SWAN data captured another surprise. On Sept. 30, the hydrogen jumped by a factor of two and a half in a single day. It dropped down again some six weeks later.

Standard models of how comets behave helped Combi’s team correlate the hydrogen signature to just how much of the comet’s surface should be giving off water, a process known as “sublimating,” because the water turns directly from ice to a vapor without passing through a liquid phase. The amount of surface area predicted didn’t jibe with what EPOXI itself saw – a comet that only gave off water from one half of its shape. But EPOXI also captured images of an extended halo of icy fragments that burst off the comet, most likely flung into space by carbon dioxide emissions on the comet’s surface. These ice chunks probably added sublimated water to the hydrogen cloud.

“The rate of water generation being so much higher in 1997 implies that the ice fragmentation was even more severe then,” says solar physicist Joe Gurman, U.S. project scientist for SOHO at NASA’s Goddard Space Flight Center in Greenbelt, Md. “To me, that means we’re watching how comets eventually ‘dry up’ and become less active with repeated passes through the inner solar system.”

Comparing EPOXI observations to SWAN’s did not, however, always jibe with current understandings of comets. EPOXI measured cyanide output – an element that tends to be fairly minimal within comets but is so bright that it is easy to measure and indeed was one of the first elements identified in comets in the 1880s. Cyanide output typically correlates to water output, but in this case EPOXI saw a burst of cyanide – it increased seven times on Sept. 17 — at a time when water production was only gently increasing.

“Analysis of all this data on Hartley 2 is just beginning,” says Combi, “So it will be awhile before we figure out all that’s happening. But we have here an example of an unusual comet. We don’t know if this one had odd behaviors or some different kind of composition – but maybe we’ll start seeing things like this, perhaps even in hindsight, in other comets.”

With only five comets privy to a near spacecraft fly-by, new data points like this can help refine our understanding of comet composition. It remains an interesting scientific debate whether anomalous comets like Hartley 2 behave differently because they formed of different materials originally or because they’ve experienced different environments over time. As more analysis of the EPOXI and SWAN data come, the next few years should provide additional insight into these remnants from the very dawn of the solar system.

Chandra X-ray Telescope images gas flowing toward black hole

NGC 3115: A lenticular galaxy located about 32 million light years from Earth. (X-ray: NASA/CXC/Univ. of Alabama/K.Wong et al, Optical: ESO/VLT) This composite image contains X-rays from Chandra (blue) and optical data from the VLT (gold) of the galaxy NGC 3115. Using the Chandra data, the flow of hot gas toward the supermassive black hole in the center of this galaxy has been imaged. This is the first time that clear evidence for such a flow has been observed in any black hole. The new Chandra data also supports the previous optical observations that suggest that NGC 3115’s black hole has a mass of about two billion times that of the Sun. This would make NGC 3115 the host of the nearest billion-solar-mass black hole to Earth. Scale: Full image: 7.5 arcmin (about 70,000 light years) | Inset image: 27 arcsec across (about 4,150 light years)

The flow of hot gas toward a black hole has been clearly imaged for the first time in X-rays. The observations from NASA’s Chandra X-ray Observatory, analyzed by University of Alabama astronomers, will help tackle two of the most fundamental problems in modern astrophysics: understanding how black holes grow and how matter behaves in their intense gravity.

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The black hole is at the center of a large galaxy known as NGC 3115, which is located about 32 million light-years from Earth. A large amount of previous data has shown material falling toward and onto black holes, but none with this clear a signature of hot gas.

By imaging the hot gas at different distances from the supermassive black hole, astronomers have observed a critical threshold where the motion of gas first becomes dominated by the black hole’s gravity and falls inward. The distance from the black hole is known as the “Bondi radius.”

“It’s exciting to find such clear evidence for gas in the grip of a massive black hole,” said Dr. Ka-Wah Wong, a post-doctoral researcher at The University of Alabama, who led the study that appears in the July 20 issue of The Astrophysical Journal Letters. ”Chandra’s resolving power provides a unique opportunity to understand more about how black holes capture material by studying this nearby object.”

As gas flows toward a black hole, it becomes squeezed, making it hotter and brighter, a signature now confirmed by the X-ray observations.

The researchers found the rise in gas temperature begins about 700 light years from the black hole, giving the location of the Bondi radius. This suggests the black hole in the center of NGC 3115 has a mass about two billion times that of the sun, making it the closest black hole of that size to Earth.

The Chandra data also show that the gas close to the black hole in the center of the galaxy is denser than gas further out, as predicted. Using the observed properties of the gas and theoretical assumptions, the team then estimated that each year gas weighing about 2 percent the mass of the sun is being pulled across the Bondi radius toward the black hole.

Making certain assumptions about how much of the gas’s energy changes into radiation, astronomers would expect to find a source that is more than a million times brighter in X-rays than what is seen in NGC 3115.

“A leading mystery in astrophysics is how the area around massive black holes can stay so dim, when there’s so much fuel available to light up,” said co-author Dr. Jimmy Irwin, assistant professor in UA’s department of physics and astronomy. “This black hole is a poster child for this problem.”

There are at least two possible explanations for this discrepancy. The first is that much less material actually falls onto the black hole than flows inside the Bondi radius. Another possibility is that the conversion of energy into radiation is much less efficient than is assumed.

Different models describing the flow of material onto the black hole make different predictions for how quickly the density of the gas is seen to rise as it approaches the black hole. A more precise determination of the rise in density from future observations should help astronomers rule out some of these models.

Provided by University of Alabama

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The Coolest Stars Come Out of the Dark

June 24, 2010

Astronomers have uncovered what appear to be 14 of the coldest stars known in our universe. These failed stars, called brown dwarfs, are so cold and faint that they'd be impossible to see with current visible-light telescopes. Spitzer's infrared vision was able to pick out their feeble glow, much as a firefighter uses infrared goggles to find hot spots buried underneath a dark forest floor.

The brown dwarfs join only a handful of similar objects previously discovered. The new objects are between the temperatures of about 450 Kelvin to 600 Kelvin (350 to 620 degrees Fahrenheit). As far as stars go, this is bitter cold -- as cold, in some cases, as planets around other stars.

These cool orbs have remained elusive for years, but will soon start coming out of the dark in droves. NASA's Wide-field Infrared Survey Explorer (WISE) mission, which is up scanning the entire sky now in infrared wavelengths, is expected to find hundreds of objects of a similarly chilly disposition, if not even colder. WISE is searching a volume of space 40 times larger than that sampled in the recent Spitzer study, which concentrated on a region in the constellation Boötes. The Spitzer mission is designed to look at targeted patches of sky in detail, while WISE is combing the whole sky.

"WISE is looking everywhere, so the coolest brown dwarfs are going to pop up all around us," said Peter Eisenhardt, the WISE project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and lead author of a recent paper in the Astronomical Journal on the Spitzer discoveries. "We might even find a cool brown dwarf that is closer to us than Proxima Centauri, the closest known star."

Brown dwarfs form like stars out of collapsing balls of gas and dust, but they are puny in comparison, never collecting enough mass to ignite nuclear fusion and shine with starlight. The smallest known brown dwarfs are about 5 to 10 times the mass of our planet Jupiter -- that's as massive as some known gas-giant planets around other stars. Brown dwarfs start out with a bit of internal heat left over from their formation, but with age, they cool down. The first confirmed brown dwarf was announced in 1995.

"Brown dwarfs are like planets in some ways, but they are in isolation," said astronomer Daniel Stern, co-author of the Spitzer paper at JPL. "This makes them exciting for astronomers -- they are the perfect laboratories to study bodies with planetary masses."

Most of the new brown dwarfs found by Spitzer are thought to belong to the coolest known class of brown dwarfs, called T dwarfs, which are defined as being less than about 1,500 Kelvin (2,240 degrees Fahrenheit). One of the objects appears to be so cold that it may even be a long-sought Y dwarf -- a proposed class of even colder stars. The T and Y classes are part of a larger system categorizing all stars; for example, the hottest, most massive stars are O stars; our sun is a G star.

"Models indicate there may be an entirely new class of stars out there, the Y dwarfs, that we haven't found yet," said co-author Davy Kirkpatrick, a co-author of the study and a member of the WISE science team at the California Institute of Technology, Pasadena, Calif. "If these elusive objects do exist, WISE will find them." Kirkpatrick is a world expert in brown dwarfs -- he came up with L, T and Y classifications for the cooler stars.

Kirkpatrick says that it's possible that WISE could find an icy, Neptune-sized or bigger object in the far reaches of our solar system -- thousands of times farther from the sun than Earth. There is some speculation amongst scientists that such a cool body, if it exists, could be a brown dwarf companion to our sun. This hypothetical object has been nicknamed "Nemesis."

"We are now calling the hypothetical brown dwarf Tyche instead, after the benevolent counterpart to Nemesis," said Kirkpatrick. "Although there is only limited evidence to suggest a large body in a wide, stable orbit around the sun, WISE should be able to find it, or rule it out altogether."

The 14 objects found by Spitzer are hundreds of light-years away -- too far away and faint for ground-based telescopes to see and confirm with a method called spectroscopy. But their presence implies that there are a hundred or more within only 25 light-years of our sun. Because WISE is looking everywhere, it will find these missing orbs, which will be close enough to confirm with spectroscopy. It's possible that WISE will even find more brown dwarfs within 25-light years of the sun than the number of stars known to exist in this space.

"WISE is going to transform our view of the solar neighborhood," said Eisenhardt. We'll be studying these new neighbors in minute detail -- they may contain the nearest planetary system to our own."

Other authors of the Spitzer paper are Roger Griffith and Amy Mainzer of JPL; Ned Wright, A.M. Ghez and Quinn Konopacky of UCLA; Matthew Ashby and Mark Brodwin of the Harvard-Smithsonian Center for Astrophysics, Cambridge; Mass., Michael Brown of Monash University, Australia; R.S. Bussmann of the University of Arizona, Tucson; Arjun Dey of National Optical Astronomy Observatory, Tucson, Ariz.; Eilat Glikman of Caltech; Anthony Gonzalez and David Vollbach of the University of Florida, Gainesville; and Shelley Wright of the University of California, Berkeley.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.


For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer. More information about WISE is online at http://wise.astro.ucla.edu and http://www.nasa.gov/wise.

Earliest watery black hole discovered

Water really is everywhere. Two teams of astronomers, each led by scientists at the California Institute of Technology (Caltech), have discovered the largest and farthest reservoir of water ever detected in the universe. Looking from a distance of 30 billion trillion miles away into a quasar—one of the brightest and most violent objects in the cosmos—the researchers have found a mass of water vapor that's at least 140 trillion times that of all the water in the world's oceans combined, and 100,000 times more massive than the sun.
Because the quasar is so far away, its light has taken 12 billion years to reach Earth. The observations therefore reveal a time when the universe was just 1.6 billion years old. "The environment around this quasar is unique in that it's producing this huge mass of water," says Matt Bradford, a scientist at NASA's Jet Propulsion Laboratory (JPL), and a visiting associate at Caltech. "It's another demonstration that water is pervasive throughout the universe, even at the very earliest times." Bradford leads one of two international teams of astronomers that have described their quasar findings in separate papers that have been accepted for publication in the Astrophysical Journal Letters.

A quasar is powered by an enormous black hole that is steadily consuming a surrounding disk of gas and dust; as it eats, the quasar spews out huge amounts of energy. Both groups of astronomers studied a particular quasar called APM 08279+5255, which harbors a black hole 20 billion times more massive than the sun and produces as much energy as a thousand trillion suns.

Since astronomers expected water vapor to be present even in the early universe, the discovery of water is not itself a surprise, Bradford says. There's water vapor in the Milky Way, although the total amount is 4,000 times less massive than in the quasar, as most of the Milky Way's water is frozen in the form of ice.

Nevertheless, water vapor is an important trace gas that reveals the nature of the quasar.

In this particular quasar, the water vapor is distributed around the black hole in a gaseous region spanning hundreds of light-years (a light-year is about six trillion miles), and its presence indicates that the gas is unusually warm and dense by astronomical standards. Although the gas is a chilly 󈞡 degrees Celsius (󈞫 degrees Fahrenheit) and is 300 trillion times less dense than Earth's atmosphere, it's still five times hotter and 10 to 100 times denser than what's typical in galaxies like the Milky Way.



This artist's concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the black hole, with clouds of charged gas above and below. X-rays emerge from the center, while dust throughout the torus emits infrared radiation. While this figure shows the quasar's torus approximately edge-on, the torus around APM 08279+5255 is likely positioned face-on from our point of view. Credit: NASA/ESA


The water vapor is just one of many kinds of gas that surround the quasar, and its presence indicates that the quasar is bathing the gas in both X-rays and infrared radiation. The interaction between the radiation and water vapor reveals properties of the gas and how the quasar influences it. For example, analyzing the water vapor shows how the radiation heats the rest of the gas. Furthermore, measurements of the water vapor and of other molecules, such as carbon monoxide, suggest that there is enough gas to feed the black hole until it grows to about six times its size. Whether this will happen is not clear, the astronomers say, since some of the gas may end up condensing into stars or may be ejected from the quasar.


Bradford's team made their observations starting in 2008, using an instrument called Z-Spec at the Caltech Submillimeter Observatory (CSO), a 10-meter telescope near the summit of Mauna Kea in Hawaii. Z-Spec is an extremely sensitive spectrograph, requiring temperatures cooled to within 0.06 degrees Celsius above absolute zero. The instrument measures light in a region of the electromagnetic spectrum called the millimeter band, which lies between infrared and microwave wavelengths. The researchers' discovery of water was possible only because Z-Spec's spectral coverage is 10 times larger than that of previous spectrometers operating at these wavelengths. The astronomers made follow-up observations with the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), an array of radio dishes in the Inyo Mountains of Southern California.

This discovery highlights the benefits of observing in the millimeter and submillimeter wavelengths, the astronomers say. The field has developed rapidly over the last two to three decades, and to reach the full potential of this line of research, the astronomers—including the study authors—are now designing CCAT, a 25-meter telescope to be built in the Atacama Desert in Chile. CCAT will allow astronomers to discover some of the earliest galaxies in the universe. By measuring the presence of water and other important trace gases, astronomers can study the composition of these primordial galaxies.

The second group, led by Dariusz Lis, senior research associate in physics at Caltech and deputy director of the CSO, used the Plateau de Bure Interferometer in the French Alps to find water. In 2010, Lis's team was looking for traces of hydrogen fluoride in the spectrum of APM 08279+5255, but serendipitously detected a signal in the quasar's spectrum that indicated the presence of water. The signal was at a frequency corresponding to radiation that is emitted when water transitions from a higher energy state to a lower one. While Lis's team found just one signal at a single frequency, the wide bandwidth of Z-Spec enabled Bradford and his colleagues to discover water emission at many frequencies. These multiple water transitions allowed Bradford's team to determine the physical characteristics of the quasar's gas and the water's mass.

More information: "Discovery of water vapor in the high-redshift quasar APM 08279+5255 at Z=3.91," Astrophysical Journal Letters.

Provided by California Institute of Technology