Tiny magnetic fields created shortly after the Big Bang may help explain the long-running disagreement over how fast the universe is expanding. Detailed simulations show that these primordial fields could have changed the formation of hydrogen in the early universe, affecting the cosmic microwave background and the expansion rate inferred from it.
Weak magnetic fields, which may have arisen shortly after the Big Bang, are able to explain some of the discrepancies in measurements of the expansion rate of the universe. Simulations showed that they could influence hydrogen formation and the cosmic microwave background.