This One Picture Will Make You Realize How Big The Universe Actually Is


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Milky Way Galaxy (Click Image to Download)

We’ve all heard the universe is a very big place, but this image from Alex Grossman really drives that concept home.

The question: How far has humanity’s influence reached?

The very first thing created by humanity that left our tiny planet wasn’t a satellite or space ship, it was the broadcasts from a world obsession with radio. This image shows how far radio broadcasts will have reached in our galaxy, the Milky Way, by the time that technology is 200 years old. Considering we only started broadcasting in 1880, this map actually represents our reach in 2080.

In the vacuum of space radio waves travel at the speed of light, so our entire influence on the universe has now traveled just 135 light years away from Earth (1 “light year” equals the distance light travels in 1 year). That’s right, the tiny blue dot in the image below is how far every single action by humanity has reached. Feel tiny yet?

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How does that compare to our furthest traveling spacecraft? The Voyager 1, which is now traveling almost outside the influence of our Sun, is only about 18 light hours away from the Earth. That’s about 97,000 times smaller than the blue dot in these pictures.

Now for the real kicker.

How many galaxies like our Milky Way are in the entire Universe? No one knows the actual figure because we can’t see to the outside edge (if there is one), but the amount we can see in the observable universe is estimated to be… wait for it…

…more than 170 billion galaxies.

There it is. We are really, really, very, amazingly, incredibly, so, small.
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Milky Way galaxy rendering by Nick Risinger

Source : www.visualnews.com

‘Perfect Storm’ Suffocating Star Formation around a Supermassive Black Hole


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High-energy jets powered by supermassive black holes can blast away a galaxy’s star-forming fuel — resulting in so-called “red and dead” galaxies: those brimming with ancient red stars yet little or no hydrogen gas available to create new ones.

Now astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered that black holes don’t have to be nearly so powerful to shut down star formation. By observing the dust and gas at the center NGC 1266, a nearby lenticular galaxy with a relatively modest central black hole, the astronomers have detected a “perfect storm” of turbulence that is squelching star formation in a region that would otherwise be an ideal star factory.

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Fig 1. Artist impression of the central region of NGC 1266. The jets from the central black hole are creating turbulence in the surrounding molecular gas, suppressing star formation in an otherwise ideal environment to form new stars. Credit: B. Saxton (NRAO/AUI/NSF)

This turbulence is stirred up by jets from the galaxy’s central black hole slamming into an incredibly dense envelope of gas. This dense region, which may be the result of a recent merger with another smaller galaxy, blocks nearly 98 percent of material propelled by the jets from escaping the galactic center.

“Like an unstoppable force meeting an immovable object, the molecules in these jets meet so much resistance when they hit the surrounding dense gas that they are almost completely stopped in their tracks,” said Katherine Alatalo, an astronomer with the California Institute of Technology in Pasadena and lead author on a paper published in the Astrophysical Journal. This energetic collision produces powerful turbulence in the surrounding gas, disrupting the first critical stage of star formation. “So what we see is the most intense suppression of star formation ever observed,” noted Alatalo.

Previous observations of NGC 1266 revealed a broad outflow of gas from the galactic center traveling up to 400 kilometers per second. Alatalo and her colleagues estimate that this outflow is as forceful as the simultaneous supernova explosion of 10,000 stars. The jets, though powerful enough to stir the gas, are not powerful enough to give it the velocity it needs to escape from the system.

Continue reading ‘Perfect Storm’ Suffocating Star Formation around a Supermassive Black Hole

Isro gets closer to manned mission, tests crew module


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ISRO’s GSLV Mark III (Click Image to Download)

This rocket didn’t put a satellite in orbit. In fact, its payload plunged into the Bay of Bengal 20 minutes after the vehicle lifted off from Sriharikota. And that made it a success, for it was the first step to India’s manned space mission.

Indian Space Research Organisation (ISRO) achieved success of a different kind on Thursday when its GSLV Mark III on a suborbital experimental flight carried an unmanned crew module which was ejected at a height of 126km. Re-entering the atmosphere, its parachutes ensured a soft-thud on the sea. Recovered by the Indian Coast Guard, the Crew Module Atmospheric Re-entry Experiment (CARE) will undergo tests to ascertain its efficiency in bringing back future astronauts from India.

“Everything went as per plan,” said ISRO chairman K Radhakrishnan. “After a decade of developing the GSLV Mk II, we have tasted the first success of an experimental flight. The performances of the solid and liquid stages were as expected. The unmanned crew module worked extremely well.”

Source : Times of india

New Signal May Be Evidence of Dark Matter


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Scientists say they may have discovered a possible dark matter signal coded in the X-rays emanating from two bright objects in the sky.

The findings, set to be published next week in Physical Review Letters, could offer tangible evidence for the existence of dark matter — and help researchers build new tools to search for and study this mysterious stuff.

When it comes to matter in the universe, dark matter is like a backroom political power broker: You never see it, but behind the scenes, it’s been throwing its weight around. The effects of its gravitational influence can be seen in the large-scale structures of the cosmos. Dark matter makes up about 84.5% of the matter in the universe while all the stuff we actually see — stars, galaxies, planets, ourselves — makes up the remaining 15.5%. The enormous galaxies and clusters of galaxies that populate the universe are bantamweights compared to the massive, unseen dark matter ‘halos’ that anchor them.

Dark matter’s formidable gravitational influence is the only way that the strange stuff can be detected, because it’s invisible — it does not interact with light. Physicists have no idea what it’s made of, although they’ve looked for it by building detectors in underground former gold mines, sending satellites into space and other methods.

But now, a team led by researchers at Leiden University in the Netherlands and the École Polytechnique Fédérale de Lausanne in Switzerland say they’ve discovered a signal that could be a sign of dark matter.

The scientists looked at X-ray emissions coming from the Andromeda galaxy and the Perseus galaxy cluster, collected by the European Space Agency’s XMM-Newton space telescope. After accounting for all the light particles (called photons) emanating from known sources in the Andromeda galaxy, they were left with a strange set of photons that had no known source. The found the same light signature emanating from the Perseus cluster. And when they turned their attention to the Milky Way, they found signs of this signal in our home galaxy, as well.

“It is consistent with the behavior of a line originating from the decay of dark matter particles,” the authors wrote in a pre-print of the study.

This weird light signal, they think, could be coming from the destruction of a hypothetical particle called a sterile neutrino (which, if it exists, might help explain dark matter). But it’s going to take a lot of follow-up study to determine whether this signal is a scientific breakthrough or an anomalous blip.

“Future detections or non-detections of this line in multiple astrophysical targets may help to reveal its nature,” the study authors wrote.

Japan’s upcoming Astro-H mission, they said, might allow them to do just that.

Source :Science Tech Today

Amazing details of Saturn & its moons captured by NASA


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Image of Saturn Taken by Cassini Space Probe (Click Image to Download)

NASA’s Cassini spacecraft has been studying Saturn and its moons for a decade now, routinely delivering stunning images of the second largest planet in our solar system. One of its noteworthy achievements is that it is now shedding a lot more light on six moons that were once shrouded in mystery.

When NASA’s Voyager spacecraft flew by moons like Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus back in the 1980s, it sent back landmark images that were nevertheless fuzzy, incomplete, and hard to make out. Now, Cassini has plugged the holes – with bursts of color, no less – and delivered stunning new images of these icy satellites.

Here is a before/after shot of Mimas showcasing the differences between Voyager’s image (left) and Cassini’s (right).

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“The most obvious [discoveries] are differences in color and brightness between the two hemispheres of Tethys, Dione and Rhea,” wrote Preston Dyches of NASA’s Jet Propulsion Laboratory. “The dark reddish colors on the moons’ trailing hemispheres are due to alteration by charged particles and radiation in Saturn’s magnetosphere.”

“Except for Mimas and Iapetus, the blander leading hemispheres of these moons – that is, the sides that always face forward as the moons orbit Saturn – are all coated with icy dust from Saturn’s E-ring, formed from tiny particles erupting from the south pole of Enceladus.”

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You can view the rest of the images here. Impressively, however, these aren’t the only photographs of Saturn and its moons making headlines this week.

Source : RT.com

ALMA Identifies Gas Spirals as a Nursery of Twin Stars


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With new Atacama Large Millimeter/submillimeter Array (ALMA) observations, astronomers led by Shigehisa Takakuwa, Associate Research Fellow at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taiwan, have found spiral arms of molecular gas and dust around “baby twin” stars. Gas motions supplying materials to the twin were also identified. These results unveil for the first time, the mechanism of the birth and growth of binary stars, which are ubiquitous throughout the Universe. The study was published on November 20 in The Astrophysical Journal.

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Fig 1. Gas and dust disks around L1551 NE spotted by ALMA. Credit: ALMA (ESO/NAOJ/NRAO) / Takakuwa et al.

Stars form in interstellar clouds of molecular gas and dust. Previous studies of star formation focused primarily on single stars like the Sun, and a standard picture of single star formation has been established. According to this picture, a dense gas condensation in an interstellar cloud collapses gravitationally to form a single protostar at the center. Previous observations have found such collapsing gas motions feeding material toward the central protostars.

Compared to single star formation, our understanding of binary star formation has been limited, even though more than half of stars with a mass similar to that of the Sun are known to be binaries. It is thus crucial to observe the physical mechanism of binary formation to obtain a more comprehensive understanding of star formation. Theory suggests that a disk surrounding a young binary will feed material to the central “baby twin” in order for them to grow. While recent observations have found such disks (known as “circumbinary disks”), it was not possible to image the structure and gas motions because of the insufficient imaging resolution and sensitivity.

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Fig 2. Comparison of the disks in simulation and observation. The right panel shows the disk image simulated with ATERUI, and the left panel the real ALMA image. Credit: ALMA (ESO/NAOJ/NRAO)/ Takakuwa et al.

Continue reading ALMA Identifies Gas Spirals as a Nursery of Twin Stars

Cool gases ideal for star formation in galaxies


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Horsehead nebula (Click Image to Download)

Astronomers have discovered that a cool cosmic environment is ideal for the creation of new stars.

A surge of warm gas from a nearby galaxy – left over from the devouring of a separate galaxy – eliminates star formation by agitating the available chilled gas, the study says.

Astronomers wanted to understand why galaxies in the local universe fall into two major categories: younger, star-forming spirals (like our own Milky Way) and older ellipticals in which fresh star making has ceased.

The new study observed galaxy NGC 3226, which occupies a transitional middle ground so getting a lead on its star formation was critical.

“We have explored big data archives from NASA and European Space Agency’s space telescopes to pull together a picture of an elliptical galaxy that has undergone huge changes in its recent past due to violent collisions with its neighbours,” said Philip Appleton, project scientist for the NASA Herschel Science Center at the California Institute of Technology in Pasadena.

These collisions are modifying the condition of the gas that resides in it, making it hard for the galaxy to form many stars, he added.

NGC 3226 is relatively close, just 50 million light-years away from Earth.

The data from the three telescopes finds that NGC 3226 has a very low rate of star formation.

It appears that in this case, the material falling into NGC 3226 is heating up as it collides with other galactic gas and dust, quenching star formation instead of fueling it.

As the warm gas flooding NGC 3226 cools to star-forming temperatures, the galaxy should get a second wind, the authors said.

The paper appeared on Astrophysical Journal.

Source : ZEE NEWS

From the Hubble, a new image of a glittering cosmic wonderland with stars as old as the universe itself


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It kind of looks like a snow globe — or maybe like the glittering ornament atop a massive Christmas tree.

Or like your neighbor’s house during December, if you’re lucky enough to live next to an aggressive seasonal decorator.

But this image from the Hubble Space Telescope shows Messier 92. Messier 92 is a globular cluster, or a spherical group of old stars bound tightly together by gravity. Their density can make globular clusters appear quite bright, and this is one of the brightest in our whole galaxy.

You may even have seen this cosmic bauble before. It’s over 25,000 light years away from Earth, but with 330,000 stars packed tightly into it, it’s often visible with the naked eye. You can catch its occasional appearances in the constellation Hercules.

Astronomers know from Messier 92’s molecular composition that it isn’t just bright — it’s also very old. About as old as the universe itself, in fact.

Like this image? You could have been the one to create it. A version of this photo was submitted by Gilles Chapdelaine as part of the Hubble’s Hidden Treasures image competition. The Hubble has beamed back so much data that not all of it has been translated into visible images, but the public is welcome to sift through archives to try to find stellar shots worth sharing.Find out more at the Hubble Web site.

Source : Washington post

Discovery of a Pulsar and Supermassive Black Hole Pairing Could Help Unlock the Enigma of Gravity


Last year, the very rare presence of a pulsar (named SGR J1745-2900) was also detected in the proximity of a supermassive black hole (Sgr A**, made up of millions of solar masses), but there is a combination that is still yet to be discovered: that of a pulsar orbiting a ‘normal’ black hole; that is, one with a similar mass to that of stars.

The intermittent light emitted by pulsars, the most precise timekeepers in the universe, allows scientists to verify Einstein’s theory of relativity, especially when these objects are paired up with another neutron star or white dwarf that interferes with their gravity. However, this theory could be analysed much more effectively if a pulsar with a black hole were found, except in two particular cases, according to researchers from Spain and India.

Pulsars are very dense neutron stars that are the size of a city (their radius approaches ten kilometres), which, like lighthouses for the universe, emit gamma radiation beams or X-rays when they rotate up to hundreds of times per second. These characteristics make them ideal for testing the validity of the theory of general relativity, published by Einstein between 1915 and 1916.

“Pulsars act as very precise timekeepers, such that any deviation in their pulses can be detected,” Diego F. Torres, ICREA researcher from the Institute of Space Sciences (IEEC-CSIC), explains to SINC. “If we compare the actual measurements with the corrections to the model that we have to use in order for the predictions to be correct, we can set limits or directly detect the deviation from the base theory.”

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These deviations can occur if there is a massive object close to the pulsar, such as another neutron star or a white dwarf. A white dwarf can be defined as the stellar remnant left when stars such as our Sun use up all of their nuclear fuel. The binary systems, comprised of a pulsar and a neutron star (including double pulsar systems) or a white dwarf, have been very successfully used to verify the theory of gravity.

Until now scientists had considered the strange pulsar/black hole pairing to be an authentic ‘holy grail’ for examining gravity, but there exist at least two cases where other pairings can be more effective. This is what is stated in the study that Torres and the physicist Manjari Bagchi, from the International Centre of Theoretical Sciences (India) and now postdoc at the IEEC-CSIC, have published in the Journal of Cosmology and Astroparticle Physics. The work also received an Honourable Mention in the 2014 Essays of Gravitation prize.

The first case occurs when the so-called principle of strong equivalence is violated. This principle of the theory of relativity indicates that the gravitational movement of a body that we test only depends on its position in space-time and not on what it is made up of, which means that the result of any experiment in a free fall laboratory is independent of the speed of the laboratory and where it is found in space and time.

The other possibility is if one considers a potential variation in the gravitational constant that determines the intensity of the gravitational pull between bodies. Its value is G = 6.67384(80) x 10-11 N m2/kg2. Despite it being a constant, it is one of those that is known with the least accuracy, with a precision of only one in 10,000.

In these two specific cases, the pulsar-black hole combination would not be the perfect ‘holy grail’, but in any case scientists are anxious to find this pair, because it could be used to analyse the majority of deviations. In fact, it is one of the desired objectives of X-ray and gamma ray space telescopes (such as Chandra, NuStar or Swift), as well as that of large radio telescopes that are currently being built, such as the enormous ‘Square Kilometre Array’ (SKA) in Australia and South Africa.

Source : Daily galaxy

The Dawn Spacecraft Is Closing in on Dwarf Planet Ceres


NASA’s Dawn spacecraft is currently en route to the asteroid belt where it will rendezvous with the region’s largest celestial body, Ceres. As a sneak preview, the spacecraft has snapped its best-yet image of the dwarf planet.

The image was snapped at a distance of 740,000 miles (1.2 million km) from Ceres. The dwarf planet features an average diameter of about 590 miles (950 km).

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At 9-pixels wide, the image isn’t much. It doesn’t hold a candle to the one previously snapped by the Hubble Space Telescope:

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But just wait until Dawn arrives at Ceres. In early 2015, the spacecraft will begin delivering images at much higher resolution.

Since launching in 2007, Dawn has visited Vesta, a giant protoplanet currently located 104 million miles (168 million kilometers) away from Ceres.

Images: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Source : io9.com