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Planck sheds new light on the ancient Universe

Paul Sutherland, Feature writer
Mar 22, 2013, 7:00 UTC

Sen—A European space mission has peered billions of years back in time to produce the most accurate and detailed map ever of the first light produced by the Universe.

Results from the Planck space telescope show a picture of the cosmic microwave background - an echo of the radiation left after the Big Bang that created everything.

It paints a picture of the sky as it must have looked before galaxies formed, when the Universe was only 380,000 years old. That was a time when the young cosmos was like a hot soup of atomic particles at a searing temperature of around 2,700C.

The map produced by Planck suggests that the Universe is expanding more slowly than astronomers believed, and has an age of 13.8 billion years - 100 million years more than previously estimated. The data also show there is less dark energy and more matter in the universe than previously known.

NASA scientists contributed to the Planck mission which was launched together with the Herschel space telescope from French Guiana in 2009.

Joan Centrella, Planck program scientist at NASA HQ in Washington, said: “Astronomers worldwide have been on the edge of their seats waiting for this map.

“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 endeavour.”

The new map of the early sky is based on the Planck mission’s first 15.5 months of all-sky observations. It 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.

Planck in spaceAn artist's impression of Planck operating in space. Credit: ESA

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

Planck has been scanning the skies since launch, mapping the cosmic microwave background. Overall, its results provide an excellent confirmation of the standard model of cosmology at an unprecedented accuracy.

But the detailed precision has also revealed some peculiar unexplained features that might need new physics to be understood.

Jean-Jacques Dordain, ESA’s Director General, said: “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.”

One puzzle is a cold spot, centred in the constellation of Eridanus, the river, that extends over a much larger patch of sky than expected. An earlier mission, NASA’s WMAP, had already suggested it was there.

Paolo Natoli, of the University of Ferrara, Italy, said: “The fact that Planck has made such a significant detection of these anomalies erases any doubts about their reality. It can no longer be said that they are artefacts of the measurements. They are real and we have to look for a credible explanation.”