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Title: Is the EDGES 78 MHz absorption trough a real cosmological signal?
Plain: In 2018 the EDGES radio experiment reported a dip in the radio sky from hydrogen gas 180 million years after the Big Bang, twice as deep as theory allows. Another experiment did not see it.
Precise: EDGES reported a flattened absorption profile centered at $78\,\mathrm{MHz}$ ($z \sim 17$) with depth $\sim 0.5\,\mathrm{K}$, at least twice the maximum in standard models without extra cooling or radio background. SARAS 3 (2022) found no such signal. Answer whether a global 21-cm absorption of that shape and depth exists, using an independent instrument with residuals below $\sim 50\,\mathrm{mK}$.
Settled by: Independent global-signal measurements (REACH, LEDA, PRIzM, lunar far-side experiments) with different antennas and sites.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: SARAS 3 (2022) rejected the EDGES profile at about 95 percent confidence; no independent confirmation exists.
Posed since: 2018