Eventually, this neutral hydrogen gas clumped together under gravity, triggering the formation of the first stars that erupted with powerful X-rays. In their cosmic dawn quest, the project's researchers have been busy probing another source of ancient radiation called the cosmic microwave background, or the CMB. This could mean that there was more radiation than predicted at cosmic dawn, or that the neutral hydrogen was being cooled by something. In other words, this research could refine the search for dark matter and explain why physicists haven't yet worked out what it is. If dark matter is amplifying this signal, astronomers should see a distinct pattern.