What the Universe tried to hide: The 21-centimeter signal explained

Astronomers have devised a method to study the universe's first stars by analyzing a 21-centimeter radio signal from hydrogen atoms, originating 100 million years post-Big Bang. This signal could reveal key information about early star properties. Projects like REACH and the Square Kilometre Array aim to capture and analyze this signal, potentially unveiling Cosmic Dawn mysteries. Researchers have modeled how early star populations affect the signal, offering insights into the universe's transition from darkness to light.