Using a telescope high in Chile's Atacama desert, a group of scientists operating under the POLARBEAR project have made the most accurate measurement yet of cosmic microwave polarization, offering clues about the origins of the Universe, new research describes.
"It's a really important milestone," Kam Arnold from UC San Diego's Center for Astrophysics and Space Sciences, and corresponding author of the report, said in a statement. "We're in a new regime of more powerful, precision cosmology."
Cosmic microwave background (CMB) radiation is light left over from the Big Bang 13.8 million years ago. The subsequent expansion of the Universe caused this radiation to cool and light to stretch into the microwave portion of the electromagnetic spectrum.
To detect the Universe's oldest light and possibly reveal a little about our cosmic history, a team of 70 cosmologists operating under POLARBEAR measured this remnant radiation using sensitive instruments called bolometers. Arrayed in the telescope, the bolometers record the direction of the light's electrical field from multiple points in the sky.
"It's a map of all these little directions that the light's electric field is pointing," Arnold explained.
The scientists were thereby able to view this light with a resolution on a scale of about three arcminutes, just one-tenth the diameter of the full Moon.
Such high resolution mapping also allowed the team to view what are known as B modes, twists in the patterns of polarization. The presence of B modes is a sign the microwave light has been warped, possibly by dark matter or remote particles called neutrinos.
Galactic dust, which also emits this type of polar radiation, can interfere with attempts to measure CMB radiation. But in this case, Arnold said he and his team are confident that the three areas they studied are mostly dust-free.
"We are confident that these B modes are cosmological rather than galactic in origin," he said.
The researchers plan to follow up this report, published in The Astrophysical Journal, by expanding the map of cosmic microwave polarization using the telescopes of the Simon Array.