Astronomers operating the powerful Atacama Cosmology Telescope (ACT) in Chile have used the observatory’s unmatched abilities to “time travel” and view the universe during a period 99.99% of the way into its ancient past.
Although previous telescopes have looked deep into the past by observing light from a few million years after the Big Bang, an event most models estimate at around 13.8 billion years ago, the research team utilizing the ACT observed light from only 380 thousand years after the Big Bang.
A pair of studies describing the findings also confirm the standard model of cosmology and offer compelling findings regarding the cosmological conundrum known as the Hubble Tension. The researchers also spotted light from several other sources, resulting in a virtual cosmic road map from the present to the beginning of time.
“We can see right back through cosmic history,” said Jo Dunkley, the Joseph Henry Professor of Physics and Astrophysical Sciences at Princeton University and the ACT analysis leader, in an announcement, “from our own Milky Way, out past distant galaxies hosting vast black holes, and huge galaxy clusters, all the way to that time of infancy.”
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Atacama Cosmology Telescope. Image credit: Debra Kellner
Scientists Use Telescope to Time Travel Back in Time
The new data from the ACT builds on several previous studies, including a time-traveling video from NASA’s James Webb Space Telescope, examining the early universe after the Big Bang when time reportedly moved five times slower than today. One study even proposed a second event called a “dark Big Bang” to explain lingering cosmic mysteries.
Although peering back to the dawn of the universe isn’t what people traditionally think of science fiction-style time travel including all of its paradoxes like the grandfather paradox, it hasn’t stopped scientists from searching for ways to directly study the past. For example, researchers designed a time-traveling quantum sensor that can gather data from the past, while another team studied a form of bizarre tachyons that could send data back in time without violating special relativity.
In other time-bending research, a new phase of matter called a time quasicrystal has defied previous assumptions about time and motion. Another study found that a theoretical inverse of a black hole called a white hole could be “where time begins.”
Those studies are now joined by the latest study, which used the powerful ACT telescope to peer over 99.99% of the way back in time.
New Data Offers Remarkably Clear View of Early Universe
According to a statement from the research team, they selected the ACT because they needed an observatory capable of seeing millimeter-wavelength light and collecting a five-year exposure of the entire night sky.
As hoped, the ACT provided the clearest set of images of the earliest light in the universe, called the Cosmic Microwave Background (CMB), ever recorded. The researchers say the difference in quality is due to the advanced optics used in the study, which were not previously available in existing telescopes.
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Image of the CMB captured by the ACT. Credit: ACT Collaboration; ESA/Planck Collaboration
“There are other contemporary telescopes measuring the polarization with low noise, but none of them cover as much of the sky as ACT does,” says Sigurd Naess, a researcher at the University of Oslo and a lead author of one of several papers related to the project.
“ACT has five times the resolution of Planck and greater sensitivity,” Naess added. “This means the faint polarization signal is now directly visible.”
Suzanne Staggs, director of ACT and Professor of Physics at Princeton University, agreed, noting that the new images offer unprecedented detail and data.
“[W]e’re not just seeing light and dark, we’re seeing the polarization of light in high resolution,” she explained. “That is a defining factor distinguishing ACT from Planck and other, earlier telescopes. We are seeing the first steps towards making the earliest stars and galaxies.”
The Hubble Tension and the Standard Cosmological Model
Among the most controversial mysteries facing astronomers and cosmologists is a discrepancy in the universe’s expansion rate known as the Hubble Tension. Several studies have tried to resolve the disparity between the expansion rate seen by the Hubble Telescope and other observatories, including new data from the James Webb Space Telescope that appears to confirm the Hubble Tension. So far, none have succeeded, leading one physicist to suggest we may have misunderstood the universe.
When studying their data from the ACT, the team reported finding support for the standard model of cosmology, essentially reinforcing the controversy.
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“We took this entirely new measurement of the sky, giving us an independent check of the cosmological model, and our results show that it holds up,” explained Adriaan Duivenvoorden, a research fellow at the Max Planck Institute for Astrophysics and lead author of one of the new papers outlining the ACT findings.
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Hubble Telescope. Credit: NASA.
“We have used the CMB as a detector for new particles or fields in the early universe (that might account for the tension), exploring previously uncharted terrain,” added Colin Hill, an assistant professor at Columbia University and one of the lead authors of the new papers. ‘The ACT data show no evidence of such new signals. With our new results, the standard model of cosmology has passed an extraordinarily precise test.”
According to Staggs, the team found it “slightly surprising” they didn’t find even partial evidence for exotic physics or other articles that might explain the basis of the tension. They thought a few tantalizing areas might explain the tension, but “they just weren’t there in the data.”
How Looking Back in Time Offers a Fresh Perspective
When studying right from 99.99% back in time, the research supported existing models of the universe, as the team says its findings “have ruled out a majority of competing alternatives.” The new data also concurred with the common estimate of 13.8 billion years as the universe’s age, with an uncertainty of only 0.1%. Finally, the study confirmed that all of the helium found in the universe was produced in the first three minutes after the Big Bang.
“Our new measurements of its abundance agree very well with theoretical models and with observations in galaxies,” said Thibaut Louis, CNRS researcher at IJCLab, University Paris-Saclay and one of the lead authors of the new papers.
The work has not yet gone through peer review. However, the results were presented on March 19th at the American Physical Society annual conference. The researchers believe their results offer a fresh perspective on several controversial cosmology topics that were previously unavailable. The findings could also help us gain a new perspective on the present-day universe almost 14 billion years after it began.
“By looking back to that time when things were much simpler, we can piece together the story of how our universe evolved to the rich and complex place we find ourselves in today,” said Dunkley.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him onX,learn about his books atplainfiction.com, or email him directly atchristopher@thedebrief.org.