Thursday, March 21, 2013

Astounding New Map Of The Universe , Older And Growing Slower Than Originally Thought: Oldest Light In The Universe Revealed

The Planck space mission has today released the most accurate and detailed map ever made of the oldest light in the universe. The universe according to Planck is expanding a bit more slowly than thought, and at 13.8 billion is 100 million years older than previously estimated. There is a bit less dark energy and a bit more of both normal and dark matter in the universe — although the nature of dark energy and dark matter remain mysterious.

This map shows the oldest light in our universe, as detected with the greatest precision yet by the Planck mission.
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 Image credit: ESA and the Planck Collaboration

The Planck space mission has released the most accurate and detailed map ever made of the oldest light in the universe, revealing new information about its age, contents and origins.

Planck is a European Space Agency mission. NASA contributed mission-enabling technology for both of Planck's science instruments, and U.S., European and Canadian scientists work together to analyze the Planck data.

The map results suggest the universe is expanding more slowly than scientists thought, and is 13.8 billion years old, 100 million years older than previous estimates. The data also show there is less dark energy and more matter, both normal and dark matter, in the universe than previously known. Dark matter is an invisible substance that can only be seen through the effects of its gravity, while dark energy is pushing our universe apart. The nature of both remains mysterious.
The Planck Space Observatory

“Planck’s high-precision map of the oldest light in our universe allows us to extract the most refined values yet of the universe’s ingredients,” said Lloyd Knox, a physics professor at UC Davis and the leader of the U.S. team determining these ingredients from the Planck data. UC Davis graduate student Marius Millea and postdoctoral scholar Zhen Hou also worked with Knox on the analysis.

This animation illustrates the painstaking work performed by scientists to extract the oldest light in our universe, called the cosmic microwave background, from maps of the whole sky taken by the Planck mission.

Planck sees light from just about everything in the universe, stretching back to 370,000 years after the big bang. To remove the light from the material lying between Earth and the cosmic microwave background, the satellite observes at nine frequencies of light. Certain objects glow at different frequencies, allowing their light to be removed.

Examples of light that must be subtracted are: light from star-forming regions; radio emissions from electrons traveling at closet to the speed of light; and light from dust in our Milky Way galaxy.

Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for both of Planck's science instruments. European, Canadian and U.S. Planck scientists work together to analyze the Planck data.


Image credit: ESA and the Planck  

This May, UC Davis will host back-to-back conferences on “Mining the Cosmic Frontier in the Planck Era” (May 20-22) and “Fundamental Questions in Cosmology” (May 22-24). These will be the first major meetings in the U.S. for researchers to discuss the new data.

Planck is a European Space Agency mission with collaboration from NASA. It was launched in 2009 to a point almost a million miles from Earth where it can look into deep space and map tiny differences in the cosmic microwave background, the faint glow of radiation left over from just after the big bang.

For the first 370,000 years of the universe’s existence, light was trapped inside a hot plasma, unable to travel far without bouncing off electrons. Eventually the plasma cooled enough for light particles (photons) to escape, creating the patterns of the cosmic microwave background. The patterns of light represent the seeds of galaxies and clusters of galaxies we see around us today.

Then these photons traveled through space for billions of years, making their way past stars and galaxies, before falling into Planck’s detectors. The gravitational pull of both galaxies and clumps of dark matter pulls photons onto new courses, an effect called “gravitational lensing.”

“Our microwave background maps are now sufficiently sensitive that we can use them to infer a map of the dark matter that has gravitationally-lensed the microwave photons,” Knox said. “This is the first all-sky map of the large-scale mass distribution in the Universe.”

This full-sky map from the Planck mission shows matter between Earth and the edge of the observable universe. Regions with less mass show up as lighter areas while regions with more mass are darker.
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Image credit: ESA/NASA/JPL-Caltech

The Planck observatory has produced the most detailed map to date of mass distribution in the universe.

These new data from Planck have allowed scientists to test and improve the accuracy of the standard model of cosmology, which describes the age and contents of our universe.

Based on the new map, the Planck team estimates that the expansion rate of the universe, known as Hubble’s constant, is 67.15 plus or minus 1.2 kilometers/second/megaparsec. (A megaparsec is roughly 3 million light-years.) That’s less than prior estimates derived from space telescopes, such as NASA’s Spitzer and Hubble.

The new estimate of dark matter content in the universe is 26.8 percent, up from 24 percent, while dark energy falls to 68.3 percent, down from 71.4 percent. Normal matter now is 4.9 percent, up from 4.6 percent.

At the same time, some curious features are observed that don’t quite fit with the current model. For example, the model assumes the sky is the same everywhere, but the light patterns are asymmetrical on two halves of the sky, and there is larger-than-expected cold spot extending over a patch of sky.

The Planck mission has imaged the oldest light in our universe, called the cosmic microwave background, with unprecedented precision. 
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Image credit: ESA/NASA/JPL-Caltech

“On one hand, we have a simple model that fits our observations extremely well, but on the other hand, we see some strange features which force us to rethink some of our basic assumptions,” said Jan Tauber, the European Space Agency’s Planck project scientist based in the Netherlands.

Scientists can also use the new map to test theories about cosmic inflation, a dramatic expansion of the universe that occurred immediately after its birth. In far less time than it takes to blink an eye, the universe blew up by 100 trillion trillion times in size. The new map, by showing that matter seems to be distributed randomly, suggests that random processes were at play in the very early universe on minute “quantum” scales. This allows scientists to rule out many complex inflation theories in favor of simple ones.

“Patterns over huge patches of sky tell us about what was happening on the tiniest of scales in the moments just after our universe was born,” said Charles Lawrence, the U.S. project scientist for Planck at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

This artist's animation depicts the "life" of a photon, or particle of light, as it travels across space and time, from the very early universe to the Planck satellite. By creating maps of the oldest light in the universe, Planck scientists are learning about the epic journey of light through the cosmos. The mission's maps showing this ancient light, called the cosmic microwave background, have revealed the most precise information yet about the universe's fundamental traits, such as its age, contents and the seeds of all structure, without which we would not exist.

The light's journey begins just moments after the big bang that created our universe 13.8 billion years ago. At that time, the universe was a hot plasma of electrons, protons and photons (green and red balls, and blue linear particles, respectively). The light repeatedly bounces off electrons, and as result can't travel very far. Later, about 370,000 years after the big bang, the universe cools enough for the electrons and protons to get together to form hydrogen atoms. Electrons no longer get in the way of the light, and it is free to travel.

Planck is the successor to balloon-based and space missions that helped astronomers learn a great deal from the microwave background, including NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and the Cosmic Background Explorer (COBE), which earned the 2006 Nobel Prize in Physics. Complete results from Planck, which still is scanning the skies, will be released in 2014.

Peculiar Features in Patterns of Ancient Light

The Planck mission has imaged the oldest light in our universe, called the cosmic microwave background, with unprecedented precision. The results fit well with what we know about the universe and its basic traits, but some unexplained features are observed.

The top map shows Planck's all-sky map of the cosmic microwave background, whereas the bottom map shows the largest-scale features of the map.

One of the anomalies observed by Planck, and hinted at before by previous missions, is an asymmetry in the temperature fluctuations of the ancient light across two halves of our sky. Temperature variations are represented by the different colors, with red being warmer and blue, cooler. The extent of these variations is greater on the hemisphere shown at right than the one at left. This goes against the accepted simple model of our universe, which holds that the sky is the same in all directions. Scientists are in the process of incorporating these and other anomalies into their picture of the universe.

Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for both of Planck's science instruments. European, Canadian and U.S. Planck scientists work together to analyze the Planck data.

Image credit: ESA and the Planck Collaboration
 
"Astronomers worldwide have been on the edge of their seats waiting for this map," said Joan Centrella, Planck program scientist at NASA Headquarters in Washington. "These measurements are profoundly important to many areas of science, as well as future space missions. We are so pleased to have worked with the European Space Agency on such a historic endeavor."

The map, based on the mission's first 15.5 months of all-sky observations, reveals tiny temperature fluctuations in the cosmic microwave background, ancient light that has traveled for billions of years from the very early universe to reach us. The patterns of light represent the seeds of galaxies and clusters of galaxies we see around us today.

"As that ancient light travels to us, matter acts like an obstacle course getting in its way and changing the patterns slightly," said Charles Lawrence, the U.S. project scientist for Planck at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The Planck map reveals not only the very young universe, but also matter, including dark matter, everywhere in the universe."

The age, contents and other fundamental traits of our universe are described in a simple model developed by scientists, called the standard model of cosmology. These new data have allowed scientists to test and improve the accuracy of this model with the greatest precision yet. At the same time, some curious features are observed that don't quite fit with the simple picture. For example, the model assumes the sky is the same everywhere, but the light patterns are asymmetrical on two halves of the sky, and there is a spot extending over a patch of sky that is larger than expected.

"On one hand, we have a simple model that fits our observations extremely well, but on the other hand, we see some strange features which force us to rethink some of our basic assumptions," said Jan Tauber, the European Space Agency's Planck project scientist based in the Netherlands. "This is the beginning of a new journey, and we expect our continued analysis of Planck data will help shed light on this conundrum."

The findings also test theories describing inflation, a dramatic expansion of the universe that occurred immediately after its birth. In far less time than it takes to blink an eye, the universe blew up by 100 trillion trillion times in size. The new map, by showing that matter seems to be distributed randomly, suggests that random processes were at play in the very early universe on minute "quantum" scales. This allows scientists to rule out many complex inflation theories in favor of simple ones.

"Patterns over huge patches of sky tell us about what was happening on the tiniest of scales in the moments just after our universe was born," Lawrence said.

Planck launched in 2009 and has been scanning the skies ever since, mapping the cosmic microwave background, the afterglow of the theorized big bang that created our universe. This relic radiation provides scientists with a snapshot of the universe 370,000 years after the big bang. Light existed before this time, but it was locked in a hot plasma similar to a candle flame, which later cooled and set the light free.

The cosmic microwave background is remarkably uniform over the entire sky, but tiny variations reveal the imprints of sound waves triggered by quantum fluctuations in the universe just moments after it was born. These imprints, appearing as splotches in the Planck map, are the seeds from which matter grew, forming stars and galaxies. Prior balloon-based and space missions learned a great deal by studying these patterns, including NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and the Cosmic Background Explorer (COBE), which earned the 2006 Nobel Prize in Physics.

Planck is the successor to these satellites, covering a wider range of light frequencies with improved sensitivity and resolution. Its measurements reveal light patterns as small as one-twelfth of a degree on the sky.

"Planck is like the Ferrari of cosmic microwave background missions," said Krzysztof Gorski, a U.S Planck scientist at JPL. "You fine tune the technology to get more precise results. For a car, that can mean an increase in speed and winning races. For Planck, it results in giving astronomers a treasure trove of spectacular data, and bringing forth a deeper understanding of the properties and history of the universe."

The newly estimated expansion rate of the universe, known as Hubble's constant, is 67.15 plus or minus 1.2 kilometers/second/megaparsec. A megaparsec is roughly 3 million light-years. This is less than prior estimates derived from space telescopes, such as NASA's Spitzer and Hubble, using a different technique. The new estimate of dark matter content in the universe is 26.8 percent, up from 24 percent, while dark energy falls to 68.3 percent, down from 71.4 percent. Normal matter now is 4.9 percent, up from 4.6 percent.

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