Scientists can’t agree on how fast the universe is expanding – why this matters so much for our understanding of the cosmos

It’s one of the biggest puzzles in cosmology. Why two different methods used to calculate the rate at which the universe is expanding don’t produce the same result. Known as the Hubble tension, the enigma suggests that there could be something wrong with the standard model of cosmology used to explain the forces in the universe.

Now, recent observations using the new James Webb Space Telescope (JWST) are shaking up the debate on how close the mystery is to being resolved.

In this episode of The Conversation Weekly podcast, two professors of astronomy explain why the Hubble tension matters so much for our understanding of the universe.

In February, the Nobel prize-winning physicist Adam Reiss, published a new paper. It said that new observations of far-away stars using the JWST matched those obtained by the Hubble Space Telescope.

These stars, called Cepheids, are commonly used in one method of calculating the rate at which the universe is expanding. Known as the local distance ladder, or cosmic distance ladder, this method has been around since observations first made by Edwin Hubble himself in 1929. And it generally produces a rate of expansion of........

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