The Largest void in universe Discovered


Hubble image of MACS J0717

Astronomers have detected the universe’s largest known cosmological supervoid in the Southern constellation of Eridanus.  Spanning some 1.8 billion light years !!!!!!!

(1 Light Years ~ 9 Trillion Kilometer)

It might be the single largest structure ever in the universe, and the only sign of it is nothing – just empty space 1.8 billion light years across. That’s 18,000 times larger than our entire galaxy.

the team remains mainly baffled as to why such an extensive void — in which the “density of galaxies is much lower than in the known universe” — could have actually arisen.

“This supervoid is certainly rare,” Greg Aldering, a cosmologist at Lawrence Berkeley National Lab in California, told Forbes.  “Underdense by about 30 percent, it’s not completely empty.  But what’s rare is the [spatial] extent of this void itself.”

Source : Forbes

Hubble Space Telescope turns 25 and Here are some of the Most Amazing Pictures Taken by it


Hubble Space Telescope marks 25th anniversary in orbit this week. So, There are some  best images taken by Hubble Space Telescope during its 25 years journey. These Images are 100% real and contains no CGI

Hubble has traveled 3.4 billion miles, circling Earth nearly 137,000 times and making more than 1.2 million observations of more than 38,000 celestial objects, according to the Space Telescope Science Institute in Baltimore. The most distant objects spotted by Hubble — primitive galaxies — are some 13 billion light-years away and date to within 400 million or so years of the universe’s origin, known as the Big Bang.

Hubble provides an average of 829 gigabytes of archival data every month, according to the institute. Altogether, Hubble has produced more than 100 terabytes of data.

Some of the images have description about it. if anyone wants to read image description just click that image. and  Enjoy……

Image Credit : hubblesite.org

Source:Fox news

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

Is Dark Energy Evaporating Dark Matter?


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cientists at the University of Rome and Portsmouth recently published a paper which describes dark matter slowly being engulfed by dark energy.

Dark matter is almost completely undetectable matter that astronomers and cosmologists have calculated to exist within our universe, hence the name “dark”. Whereas dark energy is an accepted model of energy that permeates all matter and space, and is responsible for the acceleration of the expansion of the universe (to find out more about the two, click on the links above)

Why are they of interest now?

In the paper, the cosmologists discuss how recent astronomical data favours the idea that dark energy grows as it interacts with dark matter, which can help explain the mechanics of the expansion of the universe.

“If the dark energy is growing and dark matter is evaporating we will end up with a big, empty, boring universe with almost nothing in it,” said the Director of Portsmouth’s Institute of Cosmology and Gravitation, Professor David Wands.

Professor Wands continues by stating that “Dark matter provides a framework for structures to grow in the Universe. The galaxies we see are built on that scaffolding and what we are seeing here, in these findings, suggests that dark matter is evaporating, slowing that growth of structure,”.

How does this play a role in the understanding of our universe?

As our understanding of the universe changes, so does our approach in pursuing more knowledge about its every aspect. In 1998, researchers observing distant supernovae found that they were fainter than expected. The most accepted explanation for the variance is that the light emitted from the supernovae traveled a greater distance than theorists had predicted. This observation lead to the conclusion that space must have expanded at an accelerating rate as it traveled. The phenomenon was later attributed to the existence of dark energy, which completely revolutionized the scientific community’s way of looking at the structure of the universe, and in essence, the very foundation of our existence.

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If dark energy continues its dominance in the Universe, every galaxy beyond our neighborhood will one day no longer be visible

Now, researchers believe that it is the evaporation of dark matter that can explain why the growth of cosmic structures, such as galaxies and clusters of galaxies, seems to be slower than expected.

The availability of more data allows researchers such as Professor Wands, to examine the mechanics and interactions of various cosmic phenomena more precisely.

“Much more data is available now than was available in 1998 and it appears that the standard model is no longer sufficient to describe all of the data. We think we’ve found a better model of dark energy,” Wands continues, “However there is growing evidence that this simple model cannot explain the full range of astronomical data researchers now have access to; in particular the growth of cosmic structure, galaxies and clusters of galaxies, seems to be slower than expected”.

The paper itself was published by the American Physical Society, and although it looks very interesting, one must keep in mind that dark energy and dark matter is a subject in which very little is understood. As more data becomes available, a finer structure of our universe can be developed, which cannot be possible without the researchers such as Prof. Wands, Dr. Marco Bruni and their research students.

Source : from quarks to quasars

Universe may face a darker future


Artist’s impression of exocomets around Beta Pictoris

New research offers a novel insight into the nature of dark matter and dark energy and what the future of our Universe might be.

Researchers in Portsmouth and Rome have found hints that dark matter, the cosmic scaffolding on which our Universe is built, is being slowly erased, swallowed up by dark energy.

The findings appear in the journal Physical Review Letters, published by the American Physical Society. In the journal cosmologists at the Universities of Portsmouth and Rome, argue that the latest astronomical data favours a dark energy that grows as it interacts with dark matter, and this appears to be slowing the growth of structure in the cosmos.

Professor David Wands, Director of Portsmouth’s Institute of Cosmology and Gravitation, is one of the research team.

He said: “This study is about the fundamental properties of space-time. On a cosmic scale, this is about our Universe and its fate.

“If the dark energy is growing and dark matter is evaporating we will end up with a big, empty, boring Universe with almost nothing in it.

“Dark matter provides a framework for structures to grow in the Universe. The galaxies we see are built on that scaffolding and what we are seeing here, in these findings, suggests that dark matter is evaporating, slowing that growth of structure.”

Cosmology underwent a paradigm shift in 1998 when researchers announced that the rate at which the Universe was expanding was accelerating. The idea of a constant dark energy throughout space-time (the “cosmological constant”) became the standard model of cosmology, but now the Portsmouth and Rome researchers believe they have found a better description, including energy transfer between dark energy and dark matter.

Research students Valentina Salvatelli and Najla Said from the University of Rome worked in Portsmouth with Dr Marco Bruni and Professor Wands, and with Professor Alessandro Melchiorri in Rome. They examined data from a number of astronomical surveys, including the Sloan Digital Sky Survey, and used the growth of structure revealed by these surveys to test different models of dark energy.
Professor Wands said: “Valentina and Najla spent several months here over the summer looking at the consequences of the latest observations. Much more data is available now than was available in 1998 and it appears that the standard model is no longer sufficient to describe all of the data. We think we’ve found a better model of dark energy.

“Since the late 1990s astronomers have been convinced that something is causing the expansion of our Universe to accelerate. The simplest explanation was that empty space – the vacuum – had an energy density that was a cosmological constant. However there is growing evidence that this simple model cannot explain the full range of astronomical data researchers now have access to; in particular the growth of cosmic structure, galaxies and clusters of galaxies, seems to be slower than expected.”
Professor Dragan Huterer, of the University of Michigan, has read the research and said scientists need to take notice of the findings.

He said: “The paper does look very interesting. Any time there is a new development in the dark energy sector we need to take notice since so little is understood about it. I would not say, however, that I am surprised at the results, that they come out different than in the simplest model with no interactions. We’ve known for some months now that there is some problem in all data fitting perfectly to the standard simplest model.”