It may be curtains for the Atacama Cosmology Telescope (ACT), but the final data from its nearly 20 years of observations have laid out a roadmap for the future investigation of the cosmos. The data, in fact, represents a significant step forward in our understanding of the evolution of the universe — confirming a complex disparity in measurements of the "Hubble constant," the speed at which the very fabric of space is expanding.
In a nutshell, here's the disparity: When measured from the local universe using what are known as "Type 1a supernovas" as standardized distance buoys, the Hubble constant equals one number. But when measured from the distant cosmos using a "fossil light" as a measuring stick, it equals a different number. This has become known as the "Hubble tension."
