On February 28, Nature published a revelational study which described what might be evidence of the first stars in the sky. The big bang is still something of a mystery to us, so to have found such key evidence would have a huge impact on understanding the origins of the universe. Detecting these first stars has been a priority for many scientists for the past few years, and now a project known as EDGES might have done just that.
EDGES, or Experiment to Detect the Global EoR (Epoch of Reionization) Signature, is a table-sized instrument with an antenna that is coupled to a radio receiver and signal processor. For the last nine years, it has been stationed in Australia, searching for signals of Cosmic Microwave Background (CMB). CMB can be thought of as the afterglow of the big bang. It’s a form of radiation that was created at the origin of the universe, and it is still omnipresent, 13 billion years later.
What EDGES has now found is a signal that has been omitted by neutral hydrogen – a hydrogen atom with one proton and one electron – which was in great abundance when the universe was first formed. Finding such a signal makes a suggestion about when the first stars came to life, which we now think was approximately 180 million years after the big bang.
Searching for the signal has been a great difficulty. As described by Andrew Pontzen, a cosmologist at University College London: “The team have to pick up radio waves and then search for a signal that’s around 0.01% of the contaminating radio noises coming from our own galaxy”.
After rigorous testing, retesting, and sorting through the various signals that EDGES was picking up, the team finally came to the conclusion that the dip in the wavelength that they were seeing was the sign of the birth of the first stars. Prior to this, our universe had been utterly black, in a period known as the Cosmic Dark Ages.
Judd Bowman, who headed up the research team, told Nature: “This is the first time we’ve seen any signal from this early in the Universe, aside from the afterglow of the big bang,”
What’s more, this tiny signal doesn’t stop with detecting the earliest stars. The dramatic dip in frequency is beyond what the theory predicts it should be. This sudden decrease might suggest that there was more radiation than predicted during the birth of stars, or that the neutral hydrogen was being cooled by something. Much more research is required to probe into either of these prospects, but there is a possibility that this could be the work of dark matter.
With such tremendous discoveries and possibilities on the horizon, it is essential that more and more data is collected to confirm these theories. Although, at present, we have no technology that is capable of looking so far back in time and space, plans for the James Webb Space Telescope to launch into action are developing every day. This telescope, costing 8.7 billion US dollars, just might be the answer to finally see the cosmic dawn.
Image credit: geralt via Pixabay