We still don’t understand a basic fact about the universe

Field notes from space-time | Our measurements of the Hubble constant can’t seem to come up with a consistent answer. What we learn next may alter our view of the cosmos, writes Chanda Prescod-Weinstein

By Chanda Prescod-Weinstein

Mark Garlick/SLP/Getty Images

IT IS nearly 100 years since we confirmed that the universe – space-time – is expanding. But we are still struggling with a basic fact: what is the rate of the expansion? Depending on how we measure a crucial number that sets this value, we seem to get different answers. The fallout of this question could drastically change our understanding of the cosmos.

In 1929, astronomer Edwin Hubble used observations of galaxies to show that there was a correlation between their velocity and their distance from us. The further away they were, the faster they seemed to be …