A new picture of the "oldest light" in the universe reveals that the universe is slightly older than previously estimated. The new estimate places the age of the universe at about 13.8 billion years old, about 80 million years older than previously thought.
The finding comes from the European Space Agency (ESA), which made the announcement on Thursday March 21. The agency generated the new estimate using its Planck satellite. Named after German physicist Max Planck, the satellite scans the "cosmic microwave background," relic radiation left by the Big Bang. A new picture taken with the satellite reveals the "oldest light" ever seen, from when the universe was only 380,000 years old.
"This is a giant leap in our understanding of the origins of the universe," said ESA director general Jean-Jacques Dordain during a press conference in Paris. "This image is the closest one yet of the Big Bang. You are looking 13.8 billion years ago."
The new data from the satellite also reveals that the universe is expanding at a slower rate than previously estimated. It showed that "normal matter," the type of matter that comprises planets, stars and humans, makes up 4.9 percent of the universe, as opposed to the previously estimated 4.5. It also found that dark matter, an unknown type of matter, makes up slightly more than previously thought, at 26.8 percent. Dark energy, the mysterious force thought to be behind the universe's accelerated expansion, was measured down to 68.3 percent from 72.8 percent.
"We've discovered a fundamental truth about the universe," says director of the Kavli Institute for Cosmology at the University of Cambridge Geoge Efstathiou. "One of our achievements is that there's less stuff that we don't understand, by a tiny amount."
The finding also reveals contradictions with the standard model, which makes different predictions for temperature fluctuations in the cosmic microwave background. The data also showed different average temperatures on opposite hemispheres of the sky, which contradicts the standard model prediction that the universe should be similar in all directions. A cold spot over a patch of sky is also much larger than predicted. The new Planck image confirms the standard model overall, but its clarity establishes some unexplained new features that might require a new type of physics for them to be understood.
"Our ultimate goal would be to construct a new model that predicts the anomalies and links them together," Efstathiou says. "But these are early days; so far, we don't know whether this is possible and what type of new physics might be needed. And that's exciting."