Speck of Interstellar Dust Obscures Glimpse of Big Bang


This map highlights a patch of sky that was thought to show the most ancient light in the universe, but is now thought to be dust.
European Space Agency 


Source: Portside

Author: Dennis Overbye

Emphasis Mine

Scientists will have to wait a while longer to find out what kicked off the Big Bang.

Last spring, a team of astronomers who go by the name of Bicep announced that they had detected ripples in space-time, or gravitational waves, reverberating from the first trillionth of a trillionth of a trillionth of a second of time — long-sought evidence that the expansion of the universe had started out with a giant whoosh called inflation.

The discovery was heralded as potentially the greatest of the new century, but after months of spirited debate, the group conceded that the result could have been caused by interstellar dust, a notion buttressed by subsequent measurements by the European Space Agency’s Planck satellite that the part of the sky Bicep examined was in fact dusty.

Now a new analysis, undertaken jointly by the Bicep group and the Planck group, has confirmed that the Bicep signal was mostly, if not all, stardust, and that there is no convincing evidence of the gravitational waves. No evidence of inflation.

“This analysis shows that the amount of gravitational waves can probably be no more than about half the observed signal,” Clem Pryke of the University of Minnesota said Friday in an interview.

“We can’t say with any certainty whether any gravity wave signals remain,” Dr. Pryke added. “Obviously, we’re not exactly thrilled, but we are scientists and our job is to try and uncover the truth. In the scientific process, the truth will emerge.”

When the galactic dust is correctly subtracted, the scientists said, there was indeed a small excess signal — a glimmer of hope for inflation fans? — but it was too small to tell if it was because of gravitational waves or just experimental noise.

The Bicep/Planck analysis was led by Dr. Pryke, one of the four Bicep principal investigators. Brendan Crill, of the California Institute of Technology and a member of Planck, acted as a liaison between the groups. They had planned to post their paper Monday, but the data was posted early, apparently by accident. It was soon taken down, but not before it set off an outburst of Twitter messages and hasty news releases.

A paper is to be posted to the Bicep website and has been submitted to the journal Physical Review Letters.

But it will be far from the final word. A flotilla of experiments devoted to the cause are underway, studying a thin haze of microwaves, known as cosmic background radiation, left from the Big Bang, when the cosmos was about 380,000 years old. Among them is a sister experiment to Bicep called Spider, led by Bill Jones of Princeton and involving a balloon-borne telescope that just completed a trip around Antarctica, as well as Bicep’s own Keck Array and the recently installed Bicep3.

At stake is an idea that has galvanized cosmologists since Alan Guth of the Massachusetts Institute of Technology invented it in 1979. Inflation theory holds that the universe had a violent and brief surge of expansion in the earliest moments, driven by a mysterious force field that exerted negative gravity. It would explain such things as why the universe looks so uniform and where galaxies come from — quantum dents in the inflating cosmos.

Such an explosion would have left faint corkscrew swirls, known technically as B-modes, in the pattern of polarization of the microwaves. So, however, does interstellar dust.

The Bicep group — its name is an acronym for Background Imaging of Cosmic Extragalactic Polarization — is led by John M. Kovac of the Harvard-Smithsonian Center for Astrophysics; Jamie Bock of Caltech; Dr. Pryke; and Chao-Lin Kuo of Stanford. They have deployed a series of radio telescopes at the South Pole in search of the swirl pattern.

Their second scope, Bicep2, detected a signal whose strength was in the sweet spot for some of the most popular models of inflation, leading to a sensational news conference attended by Dr. Guth and Andrei Linde, two of the founding fathers of inflation.

But that was before critics raised the dust question. Moreover, that result was contrary to a previous limit on the strength of gravitational waves obtained by the Planck satellite, which has scanned the entire microwave sky in search of the Big Bang’s secrets.

Planck observed the microwaves in nine frequencies, making it easy to distinguish dust. Bicep2 had only one frequency and lacked access to Planck’s data until last fall, when the two groups agreed to work together.

Dr. Bock of Caltech, in an interview at the end of what he called a long, stressful day, characterized the result as “no detectable signal.”

“I’m not discouraged,” he went on. “We’re going to have to have better data to get a definitive answer.”

In an email, Paul J. Steinhardt, a Princeton cosmologist who was a founder of inflation but turned against it in favor of his own theory of a cyclic bouncing universe, said the new results left cosmologists back where they were before Bicep.

But Dr. Linde noted that there was evidence in the new analysis for a gravitational wave signal, albeit at a level significantly lower than Bicep had reported. “This is what all of us realized almost a year ago, and it did not change,” he said in an email.

The earlier Planck result limiting gravitational waves, he said, had inspired a firestorm of theorizing, in which he and others produced a whole new class of theories relating not just to inflation, but to dark energy as well.

“So yes, we are very excited, and no, the theory did not become more contrived,” he said.

Max Tegmark, an M.I.T. expert on the cosmic microwaves, said, “It’s important to remember that inflation is still alive and well, and that many of the simplest models predict signals just below this new limit.” The next few years will be interesting, he said.

Michael Turner, a cosmologist at the University of Chicago, said he could appreciate the frustration of his colleagues, who have been wandering in the wilderness for nearly four decades looking for clues to the Beginning.

Inflation is the most important idea in cosmology since the hot Big Bang,” he said. “It is our Helen of Troy, launching a thousand experiments.”

Posted by Portside on February 1, 2015

See: http://portside.org/2015-02-02/speck-interstellar-dust-obscures-glimpse-big-bang

Big Bang’s afterglow reveals older universe

Source: Washing Post

Author: and

Cosmologists have released the most detailed “baby picture” yet of the early universe, a portrait that helps answer some of the deepest questions of science while providing enough surprises to keep scientists busy for years.

The images captured by a space telescope show the universe is 13.8 billion years old, 100 million years older than previously estimated.

(N.B.: about 0.7% older).  The results also reinforce a key theory scientists have about how the universe was formed, exploding from subatomic size to its current expanse in what one scientist described as “one nano-nano-nano-nano second after the Big Bang.” And they also revise estimates of how much matter and mysterious dark energy make up the universe.

The images form the most accurate and detailed map ever made of the oldest light in the universe, what scientists call the cosmic microwave background, a sort of afterglow left over from the Big Bang. That ancient light has traveled for billions of years from the very early universe to reach Earth. The patterns of light represent the seeds of galaxies and clusters of galaxies seen today.

The information released Thursday from the European Space Agency’s Planck space telescope “is the most sensitive and sharpest map ever” of that light, said Paul Hertz, director of astrophysics for NASA. “It’s as if we have gone from standard television to high-definition television; new and important details have become crystal-clear,” he said.But the new map raises questions: some features that don’t quite fit with the current understanding about the age, contents and fundamental characteristics of the universe, based on a simple model developed by scientists. For example, the model predicts the afterglow should look roughly the same everywhere. But the pattern is asymmetrical on two halves of the sky.

There is also an unexplained cold spot, larger than expected, that covers a patch in the southern sky.

By studying the high-resolution details of this map, he said, scientists can answer deep and fundamental questions about the history of the universe and its complex composition.

Using the first 15 months of data from the telescope, scientists created an all-sky picture of the afterglow — light imprinted on the sky when the universe was just a baby, about 370,000 years old. NASA contributed technology, and U.S., European and Canadian scientists analyzed the data.

“The extraordinary quality of Planck’s portrait of the infant universe allows us to peel back its layers to the very foundations, revealing that our blueprint of the cosmos is far from complete,” said Jean-Jacques Dordain, director general of the European Space Agency.

The results suggest the universe is expanding more slowly than scientists thought. The data also show there is less of the perplexing dark energy and more matter — both normal and dark matter — in the universe than previously known. Dark matter is an invisible substance that can be perceived only by observing the effects of gravity, while dark energy is a mysterious force thought to be responsible for pushing the universe apart.

The afterglow started out as a white-hot glow, but during 13.8 billion years, as the universe expanded by 1,100 times, it cooled. In a testament to its sensitivity, the Planck telescope measured it to be less than 3 degrees Celsius above absolute zero. The temperature typically varies by less than one 100 millionth of a degree across the sky.

By matching the data to predictions from mathematical models, scientists can assemble a surprisingly detailed picture of the universe an instant after the Big Bang.

“Imagine investigating the foundations of a house and finding that parts of them are weak,” said Francois Bouchet of the Institute d’Astrophysique de Paris. “You might not know whether the weaknesses will eventually topple the house, but you’d probably start looking for ways to reinforce it pretty quickly all the same.”The findings also test theories describing inflation, the dramatic expansion of the universe that took place immediately after its birth. In less than a blink of an eye, the universe blew up by 100 trillion trillion times in size, scientists said. The new map, by showing that matter seems to be distributed randomly, suggests that random processes were at play in the very early universe.Scientists said it was difficult to overstate the importance of the data. An early version of this map made by other satellites won a Nobel Prize in Physics in 2006 for two Americans. The background radiation was discovered accidentally in 1964 by a pair of American radio astronomers.

Scientists say the Planck space mission is cosmology’s equivalent of the human genome project.

“Just as DNA determines many individual characteristics, the map from the space probe shows the seeds from which our current universe grew,” said Marc Kamionkowski, professor of physics and astronomy at Johns Hopkins University. Cosmologists have a long road ahead, he said, to understand the detailed physical processes by which the patterns of light gave rise to stars, galaxies and planets.The Planck telescope, named for the German physicist Max Planck, the originator of quantum physics, was launched in 2009 and has been scanning the skies since, mapping the cosmic microwave background. This radiation gives scientists a snapshot of the universe 370,000 years after the Big Bang.

Emphasis Mine

see: http://www.washingtonpost.com/national/health-science/big-bangs-afterglow-reveals-older-universe/2013/03/21/88d3e788-9249-11e2-9abd-e4c5c9dc5e90_story.html