The Washington Post
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. 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.
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 the afterglow 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.
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.
“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.