The search for the ‘cosmic dawn’ of first light

Scientists at the Raman Research Institute (RRI), Bengaluru has been hoping to catch the trace of an extremely elusive sign from space — that of the birth of the first stars or what’s called “the cosmic dawn”.

What happened?

• The EDGES telescope, or the Experiment to Detect the Global Epoch of Reionization Signature (EDGES) that was placed in an Australian desert, recorded an unusual signal that the group claims is the sign of the cosmic dawn.
• However the signal’s pattern wasn’t shaped in the way cosmological models predicted and since 2018, when the EDGES result was published, there’s a flurry of interpretation on whether the instrument actually detected the Holy Grail signal, and if it did, what explained its unusual structure.
• To test this, the RRI group made an updated version of SARAS, called SARAS-3.
• Its chief distinguishing characteristic is that, unlike other radio telescopes, it can be deployed on water bodies.
• The many layers of soil were themselves a source of radio wave contamination for ground based telescopes.
• Given that the purpose is to detect a highly elusive signal, water — being of uniform layers — would be an ideal medium, the group reckoned, to make such a sensitive measurement.