Scientists find a surprising clue to why the universe’s expansion doesn’t add up

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. Scientists find a surprising clue to why the universe’s expansion doesn’t add up.

Com It’s well established that the universe is expanding, but there’s serious disagreement among scientists over how fast it’s happening. Two of our best ways of measuring the cosmic expansion rate, the Hubble constant, give answers that are stubbornly at odds. This presents a major problem in modern cosmology known as the Hubble tension.

We wondered if an idea originally proposed to solve another cosmic mystery — the origin of cosmic magnetic fields — could help us unlock the mystery of the Hubble tension. Our recently published research explores whether extremely weak magnetic fields left over from the earliest moments after the Big Bang might help us unpack the Hubble tension, while offering a glimpse into physics at energies far beyond anything achievable on Earth. The Hubble constant and tension Astronomers use the Hubble constant as a measure of how fast the universe is expanding.