# Dark energy may have flipped from negative to positive 9.5 billion years ago

Source: [Space & Time News -- ScienceDaily](https://www.sciencedaily.com/releases/2026/11/261111005901.htm) · 2026-11-13 · Space
Page: https://themorning.science/story/dark-energy-may-have-flipped-from-negative-to-positive-9-5-billion-years-ago-bcd1b15318a873c9
Kind: research · Impact: low

## In brief

- Scientists exploring an overlooked branch of an alternative gravity theory report that dark energy could have switched from negative to positive about 9.5 billion years ago.
- The finding comes from a theoretical analysis, as reported by ScienceDaily on 2026-11-13.
- The source describes dark energy as the mysterious force driving the Universe's expansion.

## Why it matters

If dark energy changed sign in the past, it would challenge the standard assumption of a constant cosmological constant and could affect how cosmologists model cosmic expansion history.

## Timeline

- 2026-11-11: Study results reported in ScienceDaily release (URL dated 2026/11/11)
- 2026-11-13: Space & Time News coverage published via ScienceDaily

## Coverage

- [Dark energy may have flipped from negative to positive 9.5 billion years ago](https://www.sciencedaily.com/releases/2026/11/261111005901.htm) — Space & Time News -- ScienceDaily, 2026-11-13

Tags: dark energy, cosmology, alternative gravity, cosmic expansion

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Brief generated by AI (claude-haiku-5-5) from the reporting listed under Coverage. Headlines belong to their publishers. The Morning Science – https://themorning.science