Qualla: Experiment to Detect the Global EoR Signature

Experiment to Detect the Global EoR Signature: Introduction

Mon, 22 Jun 2026 00:00:00 GMT

Photo credit Suzyj, CC BY-SA 4.0. The instrument that claimed to hear the dawn of the universe is about the size of a kitchen table. Two flat metal panels, a few wire-mesh sheets pinned to the desert floor, sitting in one of the quietest places on Earth for radio. They call it EDGES, the Experiment to Detect the Global EoR Signature, and in March 2018 its team announced something extraordinary in the journal Nature: a faint dip in the radio static of the sky, possibly the fingerprint of the very first stars flickering to life roughly 180 million years after the Big Bang. If true, it was a message from the cosmic dawn itself. The trouble is, almost no one has been able to confirm it.

Image: Suzyj | CC BY-SA 4.0

Experiment to Detect the Global EoR Signature: Why the Desert Has to Be Silent

Mon, 22 Jun 2026 00:00:00 GMT

Photo credit Виктор В, CC BY-SA 3.0. EDGES sits at the Murchison Radio-astronomy Observatory, on Wajarri Yamaji country some 800 kilometres north of Perth. The Wajarri name for the place, Inyarrimanha Ilgari Bundara, means 'sharing sky and stars,' and the choice is no accident. This is a legally protected radio quie...

Image: Виктор В | CC BY-SA 3.0

Experiment to Detect the Global EoR Signature: The Sound of the First Light

Mon, 22 Jun 2026 00:00:00 GMT

Photo credit Suzyj, CC BY-SA 4.0. Before the first stars, the universe was a fog of cold hydrogen, dark and featureless. When stars finally ignited, their ultraviolet light reached out and altered that gas, changing how it absorbed and emitted radiation at a characteristic 21-centimetre wavelength through a subtl...

Image: Suzyj | CC BY-SA 4.0

Experiment to Detect the Global EoR Signature: Too Strong to Be True?

Mon, 22 Jun 2026 00:00:00 GMT

Photo credit Suzyj, CC BY-SA 4.0. The signal was a puzzle from the start, because it was wrong in an interesting way: the dip was roughly twice as deep as any standard model predicted. Something had made the early hydrogen colder than it should have been. One bold explanation was that the gas had been chilled by ...

Image: Suzyj | CC BY-SA 4.0

Experiment to Detect the Global EoR Signature: A Signal Still in Doubt

Mon, 22 Jun 2026 00:00:00 GMT

Photo credit Suzyj, CC BY-SA 4.0. Confirmation has not come. In 2022 a rival Indian experiment called SARAS 3 reached comparable sensitivity, looked for the same dip, and found nothing. Its analysis suggested the EDGES detection was most likely an artifact rather than a message from the cosmic dawn. Suspicion has...

Image: Suzyj | CC BY-SA 4.0