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Astronomers find gaping hole in the Universe

University of Minnesota astronomers have found an enormous hole in the Universe, nearly a billion light-years across, empty of both normal matter such as stars, galaxies and gas, as well as the mysterious, unseen “dark matter.” While earlier studies have shown holes, or voids, in the large-scale structure of the Universe, this new discovery dwarfs them all.

“Not only has no one ever found a void this big, but we never even expected to find one this size,” said Lawrence Rudnick of the University of Minnesota astronomy professor. Rudnick, along with grad student Shea Brown and associate professor Liliya Williams, also of the University of Minnesota, reported their findings in a paper accepted for publication in the Astrophysical Journal.

Astronomers have known for years that, on large scales, the Universe has voids largely empty of matter. However, most of these voids are much smaller than the one found by Rudnick and his colleagues. In addition, the number of discovered voids decreases as the size increases.

“What we’ve found is not normal, based on either observational studies or on computer simulations of the large-scale evolution of the Universe,” Williams said.

The astronomers drew their conclusion by studying data from the NRAO VLA Sky Survey (NVSS), a project that imaged the entire sky visible to the Very Large Array (VLA) radio telescope, part of the National Science Foundation's National Radio Astronomy Observatory (NRAO). Their study of the NVSS data showed a remarkable drop in the number of galaxies in a region of sky in the constellation Eridanus, southwest of Orion.

“We already knew there was something different about this spot in the sky,” Rudnick said. The region had been dubbed the “WMAP Cold Spot,” because it stood out in a map of the Cosmic Microwave Background (CMB) radiation made by the Wilkinson Microwave Anisotopy Probe (WMAP) satellite, launched by NASA in 2001. The CMB, faint radio waves that are the remnant radiation from the Big Bang, is the earliest “baby picture” available of the Universe. Irregularities in the CMB show structures that existed only a few hundred thousand years after the Big Bang.

The WMAP satellite measured temperature differences in the CMB that are only millionths of a degree. The cold region in Eridanus was discovered in 2004.

Astronomers wondered if the cold spot was intrinsic to the CMB, and thus indicated some structure in the very early Universe, or whether it could be caused by something more nearby through which the CMB had to pass on its way to Earth. Finding the dearth of galaxies in that region by studying NVSS data resolved that question.

“Although our surprising results need independent confirmation, the slightly lower temperature of the CMB in this region appears to be caused by a huge hole devoid of nearly all matter roughly 6-10 billion light-years from Earth,” Rudnick said.

How does a lack of matter cause a lower temperature in the Big Bang’s remnant radiation as seen from Earth"

The answer lies in dark energy, which became a dominant force in the Universe very recently, when the Universe was already three-quarters of the size it is today. Dark energy works opposite gravity and is speeding up the expansion of the Universe. Thanks to dark energy, CMB photons that pass through a large void just before arriving at Earth have less energy than those that pass through an area with a normal distribution of matter in the last leg of their journey.

In a simple expansion of the universe, without dark energy, photons approaching a large mass -- such as a supercluster of galaxies -- pick up energy from its gravity. As they pull away, the gravity saps their energy, and they wind up with the same energy as when they started.

But photons passing through matter-rich space when dark energy became dominant don't fall back to their original energy level. Dark energy counteracts the influence of gravity and so the large masses don’t sap as much energy from the photons as they pull away. Thus, these photons arrive at Earth with a slightly higher energy, or temperature, than they would in a dark energy-free Universe.

Conversely, photons passing through a large void experience a loss of energy. The acceleration of the Universe's expansion, and thus dark energy, were discovered less than a decade ago. The physical properties of dark energy are unknown, though it is by far the most abundant form of energy in the Universe today. Learning its nature is one of the most fundamental current problems in astrophysics.

http://www.umn.edu

August 23, 2007

Comments

EARTH & UNIVERSE

September 3, 2007 by KRISHNA MOHAN AGRAWAL (not verified), 2 years 11 weeks ago
Comment id: 24778

Investigations In The Himalayas:-

The Hindi news paper “Hindustan”, of 20th May, 2007, informs vide a news item ‘dealing with collision of Continents’, that some experiments are being conducted in the Himalayas to investigate such processes of collision, by some scientists of several countries.
Under the leadership of Larry Brown, of Cornell University, investigations are being conducted for over a decade and a half, in Tibet, as Tibet and the Himalayas are being considered to have formed and thrust up as a result of the collision of the Indian plate with the Eurasian plate, over a period of more than fifty million years and more.
The project is called as “The International Deep Profiling Of Tibet And The Himalayas”. It is considered that the formation of the Plateau of Tibet is because of the going down of the Eurasian plate under the Indian plate, thrusting northward. Sensors recording vibrations very deep, upto a depth of 20 to 30 miles below the earth’s surface are being used to investigate the quality of rocks and their properties, so as to confirm collision etc., and its so called effects.
The information from the website reads as below:-

NMSU scientists prepare for next phase of research on Tibetan Plateau
Researchers from New Mexico State University will join other scientists from around the world this month in the fourth phase of a project on the Tibetan Plateau that intends to unlock more secrets of continent building.
Supported by a $755,000 grant from the National Science Foundation, the NMSU team, along with researchers from the University of Missouri-Columbia, Peking University and Cambridge University, will establish a network of 91 buried, broadband seismic sensors that will cover an area 600 miles long and 400 miles wide, larger than New Mexico and southern Colorado combined. This network of sensors will record earthquake activity around the world from seismic signals that travel beneath northern Tibet, which will help reveal the structure of the earth’s lithosphere – the crust and uppermost mantle.
“An earthquake goes through the earth carrying information,” said James Ni, physics professor at NMSU.
Each sensor and digital recorder will be powered by an above-ground solar panel, and will collect data for two years. These temporary stations will be checked on six-month to one-year intervals.
Leading the NMSU team are Ni and physics professor Thomas Hearn. Hearn will spend about two months in Tibet during the summer of 2007. Ni will be there about a month. Also participating from NMSU will be graduate students Xinling Wang and Gerardo Leon-Soto. Ni also hopes to involve some undergraduate students.
Also involved in the Tibetan Plateau research are the Qinghai Seismological Bureau in China and researchers from Cornell University.
Ni, who has studied the Tibetan Plateau for more than 30 years, will be participating for the third time in the four-phase INDEPTH project. The International Deep Profiling of Tibet and Himalaya began in 1992 to study the Tibetan Plateau, considered to be the best place in the world to observe the ongoing process of continent-to-continent collision.
Although numerous Chinese and international studies of the plateau have been conducted over the past two decades, INDEPTH is the first to use deep seismic reflection profiling to explore the continental lithosphere beneath the Himalayas and Tibet.
INDEPTH I studied the High Himalayas and recorded echoes from the mid-crustal detachment fault where the Indian plate slides, or even penetrates, beneath the Himalayas and southern Tibet, as well as the world’s deepest moho, which indicates the boundary between the earth’s crust and its mantle.
Ni became involved in 1994 during INDEPTH II, which studied the southern and middle Tibetan Plateau. Ni and Hearn participated in 1998 in INDEPTH III, which studied the extent of crustal melting below the central Tibetan Plateau as well as the northern extent of the Indian plate. Data from that phase are still being analyzed.
Work on INDEPTH IV, also known as Project ASCENT (Array Seismology Collaborative Experiments of Northern Tibet), is designed to study the northern boundary of the Tibetan Plateau and is expected to last until 2012.

Thanks to the first three phases of the project, scientists have a much better idea of what is happening below the surface of the earth. The collision of India and Asia, which began about 55 million years ago and created the Himalayas and the Tibetan Plateau, is still under way. Scientists believe that the leading edge of the Indian plate broke off and became lodged between the still-advancing Indian plate and the Asian plate, resulting in the greater thickness of the crust beneath the Tibetan Plateau.
“India underthrusts its own leading edge,” Ni said. The presence of water is lubricating the interface, Ni said, enabling one plate to slide by the other.
“If there’s no water, there would be no Himalaya, no Tibet,” Ni said. The formation of granites that eventually are pushed southward to the surface along the High Himalayas also indicated the presence of water, since it takes heat and water to form the rock. This was established in INDEPTH II.
And like the incremental process of continent-building, the researchers are learning more and making progress, one step at a time. “We’re just gradually solving mysteries,” Ni said. “The endeavor is never complete. We try to understand a little bit at a time.”
-------------------------
Photo is available at
http://ucommphoto.nmsu.edu/newsphoto/tibet_sensor.jpg
CUTLINE: A seismic sensor is buried during the INDEPTH III project on the Tibetan Plateau.
(Courtesy photo)
April 5, 2007
Darrell J. Pehr

Its website informs that the study was started in the year 1992 and is further extended upto the year 2012. Again with malice towards none, INDEPTH I, INDEPTH II, INDEPTH III are almost complete, Data from that phases are still being analyzed. Now Work on INDEPTH IV, also known as Project ASCENT (Array Seismology Collaborative Experiments of Northern Tibet), is designed to study the northern boundary of the Tibetan Plateau and is expected to last until 2012. This too is not going fetch any results, as the theory itself is not comprehensive, as my analysis says so. The exercise seems futile, as nothing of the sort ever exists.
There was one gentleman, Head of the some big Faculty, in a Technical Institute, who was led to a misconception about Lucknow, Capital of Uttar Pradesh, India. He would not build a house there, because of some misperceived highly seismic nature of the city, because of some very learned people. I assured him of no such ill effects of the area, and to go ahead with the project of building the house, as he already had purchased a housing plot there. I myself had the privilege of living in that area for a period of more than twenty years, and never felt a bit of any shaking, even during the Republic Day earthquake of 26th January, 2001, except a bit of some nausea, during the flag hoisting ceremony, which was more due to other causes. So Lucknow is not an area to get any devastating earthquake, so as to forbid building a house to live, peacefully there, without the fear of damages due to earthquakes.
This incident is mentioned here just to give an example of our preconceptions and mindset, prepared more so by our so called very learned and respected scientists, the world over, who normally do not use a bit of mind of their own, and do not allow for others too, and instead go by the lines, told to them, all the time. Even Mahatma Gandhi propagated for independence of not only body but thought too.

Northward thrusting of the Indian Plate:-
The Indian plate has been considered to be moving and thrusting northward.
Due to continental drift, the India Plate split from Madagascar and collided with the Eurasian Plate resulting in the formation of the Himalayas and The Bay of Bengal.
Image:Himalaya-formation.gif
( Courtesy: Wikipedia, the free encyclopedia )

EARTH & UNIVERSE

September 2, 2007 by KRISHNA MOHAN AGRAWAL (not verified), 2 years 11 weeks ago
Comment id: 24767

It is sad that most scientists, like most politicians and Head of States behave in a partial manner, and even try to divide science and scientific facts, as has been divided religion, even when we call GoD as one. We do not want to suit ourselves to the God, but a God to suit us. It is because of this reason the Earth has to bear so much burden, of man and material. This is the pitiable condition of the Earth, about which we claim to know a bit, where millions go without food and shelter, and shiver in the coldness and bask in the bitterness and hatred of the society. What would have been the condition of the Universe, if we would have known enough about it, as well. So in this atmosphere of superficial supremacy, even if some facts are known, correctly somewhere, we are not going to appreciate and believe. The plate tectonics is no doubt absurd, with malice towards none. There are other methods, more scientific and reasonable to explain the Evolution of Earth. Moreover there cannot be more than one, even. So we have to try to understand that, one and only one. That one and only one has already been told as "Krishna Mohan's concept of permanency of Continents- is the only reality", developed by this writer. As already explained it is not necessary that it will suit each and everybody's mindset. Similar is the position with the Evolution of the Universe. I am also bound by the laws of the universe. I too cannot frame my own laws, to evolve the universe, or the Earth. All are bound by the most simple and fundamental laws. We may try to make them complicated, in order to avoid compliance and affirmation. This is going to happen for a long time to come. But it does not mean that we do not make efforts, and submit meekly to absurdity.-KRISHNA MOHAN AGRAWAL, DELHI, INDIA.-2nd September, 2007.

EARTH & UNIVERSE

August 27, 2007 by KRISHNA MOHAN AGRAWAL (not verified), 2 years 12 weeks ago
Comment id: 24710

We have little knowledge of the universe, and even least about own habitat/ habitation, the Earth. Both of these are a part of the whole. We can know about the whole, if we know a tiny bit of the part correctly. A lady of the house when preparing rice or vegetables, checks a piece or two only, to ascertain about the whole, if baked or not. She does not have to check and worry about the whole. Similar is the story about the universe. If we try to clear our doubts about the Earth itself, we will be able to know about the universe, as well, even fully. I propagate "Krishna Mohan's concept of Permanency of Continents-Is the only reality", about Evolution of Earth. It means, what we see today on Earth, is as such from the beginning, though it too took shape, on the basis of a very simple scientific law of application of forces, to be told specifically later. We can explain enough about the Solar system, too on this basis, if not all. - KRISHNA MOHAN AGRAWAL, DELHI, INDIA.

nothnig

August 24, 2007 by Sezam (not verified), 2 years 12 weeks ago
Comment id: 24682

Come on... "nothing" is "nothing". Good post!

Nice write up

August 23, 2007 by Orderer (not verified), 2 years 13 weeks ago
Comment id: 24667

Is that straight from the press release for the discovery from umn?
In any case, I have wondered how they'd detect things, especially things like "nothing" :)

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