Astronomers have made history by using ground-based telescopes to observe the universe 13 billion years ago, when the first stars formed and lifted the cosmic darkness known as “Cosmic Dawn.” This achievement is thanks to the Cosmology Large Angular Scale Surveyor (CLASS), a network of telescopes in the Atacama Desert region of Northern Chile.
The team’s goal was to measure the probability of photons from the Cosmic Microwave Background (CMB) encountering electrons ripped free by the first stars, providing valuable insights into the early universe. The signal from CLASS comes from polarized microwave light, which is faint and often drowned out by natural events like atmospheric changes and human-made signals.
To overcome these challenges, the team compared data from CLASS with observations from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and the European Space Agency’s Planck space telescope. This allowed them to identify sources of interference and hone in on a signal from polarized microwave light in the CMB.
The success of this research has significant implications for our understanding of dark matter and neutrinos, two elusive particles that fill the universe. By analyzing additional CLASS data, scientists aim to refine their understanding of these phenomena and create a clearer picture of the infant cosmos.
This breakthrough is a testament to the scientific value produced by long-term support from the National Science Foundation (NSF), which has been backing CLASS since 2010. The team’s achievement marks an impressive leap forward in measurement of the cosmic microwave polarization signal, demonstrating the power of ground-based experiments in astronomy.
Source: https://www.space.com/astronomy/astronomers-see-the-1st-stars-dispel-darkness-13-billion-years-ago-at-cosmic-dawn