Ancient Twisted Pattern of Light Reveals New Information About the Early Universe

Light can take billions of years to reach Earth. In fact, some of the light astronomers witness is from the very early universe. Along its way, though, this ancient light can be distorted by the pull of matter, leading to a twisted light pattern. Now, astronomers have finally detected this twisted pattern of light, called B-modes, which could lead to better maps of matter across our universe.

Scientists have long predicted two types of B-modes. The first type are called primordial and are theorized to have been produced when the universe was a newborn baby, fractions of a second after its birth in the Big Bang. The second and most recently discovered type are ones that were generated a few billion years into our universe's existence. Since our universe is currently about 13.8 billion years old, these B-modes can tell us quite a bit about the formation of our universe.

"This latest discovery is a good checkpoint on our way to the measurement of primordial B-modes," said Duncan Hanson, one of the researchers, in a news release.

The oldest light we see around us today is called the cosmic microwave background. This light actually comes from a time just hundreds of millions of years after the universe was created. Already Planck has produced the best-ever full-sky map of this light, revealing new details about the age of the cosmos. A fraction of this light is polarized, which is a process that causes light waves to vibrate in the same plane. B-modes in particular are a twisted pattern of polarized light.

In this case, the scientists spotted the kind of polarized light spawned by matter in a process called gravitational lensing. More specifically, they examined signals with the South Pole Telescope and made the first-ever detection of B-modes. Not only is this an important step for better mapping how matter is distributed throughout our universe, but it also paves the way for detecting primordial B-modes.

"These beautiful measurements from the South Pole Telescope and Herschel strengthen our confidence in our current model of the universe," said Olivier Dore, one of the researchers, in a news release. "However, this model does not tell us how big the primordial signal itself should be. We are thus really exploring with excitement a new territory here, and a potentially very, very old one."

The findings are published in the journal Physical Review Letters.