When did the stars first flicker to life? It’s a grand question that has confounded us since we first became aware of our celestial surroundings.
And, considering the infinite unknowns of the universe — and our own speck-like vantage — it seemed a cosmic conundrum that would remain unanswered.
In a new study published this week in Nature, researchers say they have a date for that moment when the stars came to life.
Based on a faint signal emanating from the first objects in the universe, scientists have pegged the light of the first stars at 13.6 billion years ago, around 180 million years after the Big Bang.
By studying changes in the Cosmic Microwave Background, an expanse of radiated gases, scientists have discovered a surprisingly rich set of clues about the universe's distant past. These changes — caused by ultraviolet light interacting with hydrogen — hail from the very first stars in the universe, the astronomers say. As the abstract explains:
"This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz1."
For Arizona State researchers, it took a modest, fridge-sized antenna to catch the telltale signal in that radioactive haystack.
"Finding this minuscule signal has opened a new window on the early universe," lead author Judd Bowman of Arizona State University, tells the Guardian. "It’s unlikely we’ll be able to see any earlier into the history of stars in our lifetime."
The study, which involved countless replication and equipment changes to make sure the signal is real, is the culmination of 10 years of work.
Along the way, the research team may have made a second major discovery — evidence of long-elusive evidence of dark matter at work.
"If confirmed, this discovery deserves two Nobel Prizes," Harvard astronomer Avi Loeb, who wasn’t involved in the study, tells The Associated Press. "For both capturing the signal of the first stars and potential dark matter confirmation."
Of course, with a claim this momentous, the study will have to withstand intense scientific scrutiny. As Loeb notes, "extraordinary claims require extraordinary evidence."