Now, a team of scientists believe they've found a signal in the darkness, the first hint of stars emerging from the primordial soup that created everything we know. Ultraviolet radiation from these stars, astronomers also believed, would interact with hydrogen gas, which in turn absorbed some cosmic microwave background radiation left over from the big bang. We use the speed of light when measuring vast distances in the universe like the space between stars and galaxies. This updated timeline of the universe reflects the recent discovery that the first stars emerged by 180 million years after the big bang. (N.R.Fuller, National Science Foundation)So instead of visually looking for the first stars, astronomers listen using radio telescopes, then look for a signal in the data.

Source: CBC News February 28, 2018 18:00 UTC