Astronomers used ACT data to understand early universe structures

Astronomers are making progress in understanding the early universe by studying data from the Atacama Cosmology Telescope (ACT) in Chile. This telescope provides clearer images of the cosmic microwave background (CMB), which is the light emitted when the universe first became transparent after the Big Bang. The CMB is a faint glow that fills space and offers a glimpse into the universe as it was about 380,000 years after the Big Bang. ACT's observations show high-resolution polarization of light, which helps scientists understand how the gas in the early universe moved. Suzanne Staggs, the director of the ACT Consortium, stated that the telescope is capturing early steps towards the formation of stars and galaxies. ACT's data reveals subtle variations in the density of gases. By analyzing this information, researchers are able to identify the earliest structures that would evolve into galaxies. Mark Devlin, ACT's deputy director, emphasized the detailed work required to obtain these measurements over five years, using sensitive equipment. The resolution of ACT is five times better than that of the previous Planck satellite, making it easier to detect the faint polarization signals. This allows scientists to see not only where the gas was located but also how it was moving, giving insights into the gravitational forces at play in the early universe. Additionally, ACT’s data provides an understanding of the universe's mass and its expansion. Erminia Calabrese, a lead author on the studies, reported that the observable universe is almost 50 billion light-years across and contains about 1,900 times the mass of our sun. Most of this mass is made up of dark energy and dark matter, which are not visible but play a significant role in the universe's structure. These findings are crucial as they help refine the age of the universe to about 13.8 billion years. This work sets the stage for future observations with the upcoming Simons Observatory in Chile, which will continue to explore the cosmic microwave background and expand our understanding of the universe.