Is the EDGES 78 MHz absorption trough a real cosmological signal?
In plain words
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 statement
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 $\sim 50\,\mathrm{mK}$.
What would settle it
Independent global-signal measurements (REACH, LEDA, PRIzM, lunar far-side experiments) with different antennas and sites.
Status in the literature
SARAS 3 (2022) rejected the EDGES profile at about 95 percent confidence; no independent confirmation exists.