EDGES reported 21 cm absorption at redshift 17 nearly twice the maximum depth standard cosmology allows, with a flat-bottomed shape no model produces; SARAS-3, engineered to evade ground systematics, rejects the profile at 95.3 percent confidence. The first measurement of cosmic dawn is unmade, and a literature of baryon-dark-matter scattering built on the EDGES depth hangs on a disputed instrument response.
The model's 21 cm depth is capped by adiabatic gas cooling against the CMB: a deeper trough requires either colder gas, which invited dark matter interactions, or a brighter radio background, which the model's source inventory at z of 17 cannot supply. EDGES forced ΛCDM to choose between an artifact and exotica, and the replication says artifact.
SCT carries no stake in the EDGES depth and no fear of it. If SARAS-3 is right, the standard trough stands and nothing in the framework moves: SCT's thermal history at cosmic dawn is the standard one (P29, P30). If a deep absorption is ever confirmed, SCT supplies the non-exotic ingredient ΛCDM lacks: collision seeding front-loads cosmic dawn with accreting compact objects (P46), the same abundant early-black-hole demographic JWST now observes directly, and their synchrotron output raises the radio background against which 21 cm absorption is measured, deepening the trough without touching the gas temperature and without any baryon-dark-matter scattering, which the framework forbids outright (P54).
The multi-phase reheating structure (P47, P36) adds the profile shape: staggered local heating episodes flatten and structure the absorption trough relative to the smooth single-history prediction, the qualitative character EDGES claimed. So SCT's position is contingency with both branches covered by existing machinery: standard depth, fine; deep flat trough, the seeded radio background plus staggered reheating, with the dark matter interaction route closed in either case.
This is the same seeded early-accretor population behind the Little Red Dots and the neutrino-sky calorimeters. There is no need to chill the hydrogen with a particle the framework's ledger excludes.
The discriminating outcome: a confirmed deep trough demonstrated to require gas colder than any radio-background explanation permits, the background independently measured (ARCADE-2-style) and found insufficient while the depth stands, would demand baryon-dark-matter interaction and falsify SCT's no-particle ledger. Short of that, REACH and SKA-low settling the contradiction tests the contingency: a standard trough closes the episode; a deep trough requires the seeded background to be present at the level the depth demands.