Einstein’s “Biggest Blunder” Was Actually Right | NOVA | PBS

PBS NOVA
PBS NOVAMay 28, 2026

Why It Matters

The realization that cosmic expansion is accelerating reshaped fundamental physics and cosmology, introducing dark energy as a major unknown that determines the universe’s fate and challenges theoretical understanding. Resolving its nature has profound implications for particle physics, gravity, and the long-term evolution of the cosmos.

Summary

Einstein introduced the cosmological constant to force a static universe, but Hubble’s 1920s observations showed the cosmos is expanding and the discovery of the cosmic microwave background later confirmed a hot Big Bang origin. In the 1990s, Adam Riess and other teams used Type Ia supernovae as standard candles and unexpectedly found the expansion is accelerating, effectively reviving Einstein’s cosmological constant as a real physical effect. That accelerated expansion is attributed to dark energy — a mysterious repulsive component of the universe that dominates its dynamics. The film traces this arc from historical ideas to modern observational evidence that transformed cosmology.

Original Description

To keep the universe static, Albert Einstein invented something called the cosmological constant.
He later abandoned it. Decades afterward, astronomers discovered the universe’s expansion is accelerating—reviving Einstein’s controversial idea.
📺 Watch the full episode, Decoding the Universe: Cosmos https://www.pbs.org/wgbh/nova/video/decoding-the-universe-cosmos/
📰 Stay up to date on the latest science discoveries, full episodes, articles, videos, and more by signing up for NOVA's newsletter here: https://to.pbs.org/4brCC7Y
▶️ Stream NOVA documentaries & more with PBS Documentaries on Prime Video: https://amzn.to/4hXBlsu
💙 Help us bring the universe closer to home. Your donation ensures that NOVA’s deep-space discoveries and quantum physics explorations remain free and inspiring for the next generation of scientists. Support fact-based storytelling today. https://bit.ly/48UnsrD
🌟 Follow on social for more NOVA content

Comments

Want to join the conversation?

Loading comments...