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For the first time, scientists have used Earth-based telescopes to peer back into the cosmic dawn — an era more than 13 billion years ago when light from the first stars began reshaping our universe.
The residual light from this ancient epoch is millimeters in wavelength and extremely faint, meaning that although space-based observatories have been able to peer into it, the signal is drowned out by the electromagnetic radiation in Earth’s atmosphere before ground-based telescopes can detect the primordial light.
But now, by deploying a specially designed telescope, scientists at the Cosmology Large Angular Scale Surveyor (CLASS) project have detected traces that the first stars left on the background light of the Big Bang. They published their findings June 11 in The Astrophysical Journal.
“People thought this couldn’t be done from the ground,” study co-author Tobias Marriage, CLASS project leader and a professor of physics and astronomy at Johns Hopkins University, said in a statement. “Astronomy is a technology-limited field, and microwave signals from the Cosmic Dawn are famously difficult to measure. Ground-based observations face additional challenges compared to space. Overcoming those obstacles makes this measurement a significant achievement.”