A team of international astronomers has produced the clearest images yet of the universe in its infancy, revealing the earliest cosmic time accessible to humans. The Atacama Cosmology Telescope (ACT) collaboration measured light from the cosmic microwave background (CMB), which traveled 13 billion years to reach Earth, and found that the universe was about 380,000 years old at the time.
The images show the formation of ancient clouds of hydrogen and helium that later developed into the first stars and galaxies. The team’s analysis confirms a simple model of the universe, ruling out many competing alternatives. They also measured the expansion rate of space with unprecedented precision, finding it to be 67-68 kilometers per second per megaparsec.
The findings suggest that the observable universe extends almost 50 billion light years in all directions and contains as much mass as 1,900 zetta-suns. The universe’s “dark energy” or invisible dark matter makes up about three-quarters of its mass, while normal matter makes up only a small fraction.
Lead researcher Professor Erminia Calabrese said the new images allow for precise reconstruction of the processes that seeded cosmic structures in the universe. She also confirmed a lower value for the Hubble constant, which is the rate at which space is expanding today.
The research marks the end of four years’ work on ACT and paves the way for future projects like the Simons Observatory in Chile. The team’s findings strengthen the standard model of cosmology and make the universe an even more precise and complex place to study.
Source: https://phys.org/news/2025-03-astronomers-unveil-baby-pictures-stars.html