The Atacama Cosmology Telescope measures the oldest light in the universe. Credit: Debra Kellner
Astronomers with the National Science Foundation Atacama Cosmology Telescope (ACT)—an international collaboration that includes Rutgers University—have taken a fresh look at the oldest light in the universe.
Their new observations plus a bit of cosmic geometry suggest that the universe is 13.77 billion years old, give or take 40 million years.
The new estimate matches the one provided by the standard model of the universe and measurements of the same light made by the Planck satellite.
This adds a fresh twist to an ongoing debate in the astrophysics community.
A portion of a new picture of the oldest light in the universe taken by the Atacama Cosmology Telescope.In 2019, a research team measuring the movements of galaxies calculated that the universe is hundreds of millions of years younger than the Planck team predicted. That discrepancy suggested that a new model for the universe might be needed and sparked concerns that one of the sets of measurements might be incorrect.
The close agreement between the ACT and Planck results and the standard cosmological model is an important step forward, says John Hughes, a Distinguished Professor of Physics and Astronomy in the School of Arts and Sciences, Rutgers University-New Brunswick.
"This now puts the focus on the disagreement with the 2019 study of the motions of galaxies,” says Hughes. “As an astronomer I put serious weight on these galaxy measurements and so I'm excited about the possibility that new unknown physics may be at play in resolving the discrepancy."
Rutgers is a founding member of the ACT team, which emerged in the early 2000s and includes scientists from 41 institutions in seven countries. Hughes has been part of the team since its start and was involved throughout the development of the recent studies, focusing on the interpretation and presentation of the results.
Andrew Baker, a professor in the Department of Physics and Astronomy is also a member of the ACT team.
The Atacama Cosmology Telescope is a six-meter telescope located in the Atacama Desert in the north of Chile. Rutgers is also a partner in the Southern African Large Telescope consortium, a world-wide group of universities, institutions and the South African National Research Foundation that have jointly constructed a 10-meter optical telescope.
John Hughes, a Distinguished Professor of Physics and Astronomy,As ACT continues making observations, astronomers will have an even clearer picture of the CMB and a more exact idea of how long ago the cosmos began. The ACT team will also scour those observations for signs of physics that doesn't fit the standard cosmological model. Such strange physics could resolve the disagreement between the predictions of the age and expansion rate of the universe arising from the measurements of the CMB and the motions of galaxies.
“We’re continuing to observe half the sky from Chile with our telescope,” says Mark Devlin, ACT’s deputy director and the Reese W. Flower Professor of Astronomy and Astrophysics at the University of Pennsylvania. “As the precision of both techniques increases, the pressure to resolve the conflict will only grow."
This story was adapted from a news release written by Thomas Sumner of the Simons Foundation.