Astronomers have released the clearest and most detailed images ever of the universe when it was just a baby—only 380,000 years old.
These incredible “baby pictures” show what the cosmos looked like shortly after the Big Bang, over 13 billion years ago.
The images come from the Atacama Cosmology Telescope (ACT), located high in the Andes Mountains in Chile.
Scientists from around the world, including a team from Cardiff University, worked together to capture and study the light known as the cosmic microwave background (CMB).
This ancient light has been traveling through space for billions of years and gives us a snapshot of the early universe.
The new images show both the brightness and the direction (or polarization) of the earliest light in amazing detail.
This has allowed scientists to see how clouds of hydrogen and helium were beginning to form—clouds that would later become the first stars and galaxies.
By studying this light, the researchers confirmed that the current model of how the universe works is still accurate. Their findings also helped rule out other ideas that don’t match the data.
Professor Erminia Calabrese from Cardiff University said these new images help us better understand how the complex structures in the universe—including our own planet—came to be. She explained that the observable universe stretches almost 50 billion light years in every direction and contains an enormous amount of mass—equivalent to about 1,900 zetta-suns (that’s nearly two trillion trillion suns!).
Only a small part of this mass—about 100 zetta-suns—is made of normal matter, the kind we can see. Most of that is hydrogen and helium. The elements that make up humans, such as carbon, oxygen, and iron, came much later, formed in stars. The rest of the mass is invisible: 500 zetta-suns of mysterious dark matter and 1,300 zetta-suns worth of dark energy, the force believed to be making the universe expand.
One big mystery the team wanted to explore is the disagreement about how fast the universe is expanding today. Some measurements say it’s expanding at about 67–68 kilometers per second per megaparsec, while others say it’s 73–74. The new data supports the lower number and does so with greater precision than before. They also confirmed the age of the universe as 13.8 billion years, with only a tiny margin of error.
The ACT project finished collecting data in 2022, and the Cardiff team is now looking ahead to the Simons Observatory, a new and more powerful telescope at the same site. Professor Calabrese says this is a proud moment for the ACT team, as their findings help us understand what the universe was—and wasn’t—like in its earliest days.
