Scientists close in on 12 billion-yr-old signal from universe’s ‘dark age’
A star-lit night sky is something we all take for granted every time we look up. But do you know that there was a time - albeit billions of years ago - when the universe was completely “dark” and contained no stars at all?
And now a team of international scientists is closer than ever to detecting, measuring and studying a signal from this “dark age” of the universe that has been travelling through space since the end of that starless era about 13 billion years. The signal could help explain how star formation shaped the early universe, according to a report in website phys dot org.
A study by that team of researchers from the University of Washington, University of Melbourne, Curtin University and Brown University published in the Astrophysical Journal last year had claimed that it had achieved an almost 10-fold improvement of radio emission data collected by the Murchison Widefield Array telescope in Western Australia.
They are now scouring and analysing the data from the radio telescope to understand the poorly understood “dark age” of universe.
“We think the properties of the universe during this era had a major effect on the formation of the first stars and set in motion the structural features of the universe today,” said team member Professor Miguel Morales, University of Washington.
“The way matter was distributed in the universe during that era likely shaped how galaxies and galactic clusters are distributed today.”
Hydrogen atoms began to aggregate and form the first stars when the universe was just one billion years old, bringing an end to the dark age.
The signal that the researchers are looking for is an electromagnetic wave given off by the neutral hydrogen that used to populate the universe before stars formed. At the time, the signal had a 21-centimeter wavelength — but the universe’s expansion has stretched it to about two metres, according to a report in the website phys dot org.
“And it’s difficult to detect because in the 13 billion years since that signal was emanated, our universe has become a very busy place,” Morales added, “filled with other activity from stars, galaxies and even our technology that drown out the signal from the neutral hydrogen.”
That signal should contain information about the dark age and the events that ended it, Morales said.
The team has about 3,000 hours of additional emission data collected by the radio telescope. The researchers are trying to filter out interference and get even closer to that elusive signal from neutral hydrogen—and the dark age it can throw light on.