Is the universe’s expansion slowing down? Astronomers cast doubt on Nobel

Type Ia supernova from accreting white dwarf. NASA Goddard Space Flight Center Conceptual Image Lab

The universe’s expansion might not be accelerating but slowing down, a new study suggests.

If confirmed, the finding would upend decades of established astronomical assumptions and rewrite our understanding of dark energy, the elusive force that counters the inward pull of gravity in our universe.

Two separate teams of astronomers, while observing bright, exploding stars called Type 1a supernovas, put forth the idea in 1998 that dark energy might enable the universe to expand at an accelerating rate.

The scientists had noted that some of the most distant supernovas were dimmer than expected and concluded that they had moved away from Earth faster than anticipated. The discovery won