A team of researchers from the Atacama Cosmology Telescope (ACT) collaboration has released the clearest images yet of the universe’s infancy – the earliest cosmic time accessible to humans. The new images reveal the universe when it was about 380,000 years old, a period known as the “cosmic dawn.” This stage is significant because it marks the moment when light could travel freely through the universe, allowing scientists to observe the cosmic microwave background (CMB) radiation.
The CMB represents the first stage in the universe’s history that can be seen. The new images provide higher definition than previous observations, thanks to ACT’s five times greater resolution and sensitivity compared to the Planck space-based telescope. The polarization image reveals subtle variations in the density and velocity of hydrogen and helium gas in the cosmic infancy.
These images are helping scientists answer long-standing questions about the universe’s origins. By studying this period, researchers can piece together how our universe evolved into its current complex state. According to the latest findings, the observable universe extends almost 50 billion light-years in all directions from us and contains as much mass as 1,900 “zetta-suns,” or nearly 2 trillion trillion suns.
The research was supported by the U.S. National Science Foundation and Princeton University. ACT operated in Chile from 2007 to 2022 under an agreement with the University of Chile. The team’s findings are a testament to the power of cosmology measurements to probe everything from the birth of the universe to stellar outbursts.
Source: https://www.princeton.edu/news/2025/03/18/new-high-definition-images-released-baby-universe