Dark energy debunked? Cosmic acceleration may be an illusion

A new analysis of more than 1,700 supernovae is questioning whether the universe is really accelerating at all. After accounting for the ages of the stars that produce these explosions, researchers found signs that cosmic expansion may actually be slowing. They also argue that the apparent acceleration changes with direction, which would be difficult to explain with dark energy.

Other cosmologists dispute the conclusion, setting up a major test for upcoming observatories. Dark energy debunked? Cosmic acceleration may be an illusion. Cosmic acceleration may be an illusion Science News from research organizations Dark energy debunked.

Cosmic acceleration may be an illusion Date: September 8, 2026. Com A new analysis led by researchers at the Tata Institute of Fundamental Research, Mumbai, together with Professor Subir Sarkar of the University of Oxford, is challenging one of the central ideas in modern cosmology: that the universe is expanding at an accelerating rate because of "dark energy" associated with the quantum vacuum. Their letter, published in Monthly Notices of the Royal Astronomical Society, argues that the evidence for cosmic acceleration may not be as strong as widely assumed.

In the same issue of the journal, a separate paper co-authored by Professor Maria Vincenzi, also at the University of Oxford, concludes that observations continue to support an accelerating universe.