Top 10 Most Controversial Science Theories

Despite decades of elegant mathematics, string theory's requirement of extra dimensions and its lack of testable predictions have led critics to question whether it qualifies as science at all.

The hypothesis that life on Earth was seeded by microorganisms from space, championed by Fred Hoyle and Chandra Wickramasinghe, challenges conventional models of abiogenesis.

Stephen Jay Gould and Niles Eldredge's 1972 model proposing that evolution occurs in rapid bursts separated by long periods of stasis sparked decades of debate among evolutionary biologists.

James Lovelock's idea that Earth's biosphere functions as a self-regulating system was dismissed as pseudoscience by many but has since influenced mainstream Earth system science.

Fleischmann and Pons's 1989 claim of achieving nuclear fusion at room temperature caused a global sensation before widespread failure to replicate relegated it to the scientific fringe.

Fred Hoyle's model of a universe with no beginning that continuously creates matter was a serious rival to the Big Bang until cosmic microwave background radiation was detected in 1965.

Elaine Morgan's proposal that human ancestors went through a semi-aquatic phase to explain bipedalism, hairlessness, and subcutaneous fat remains popular with the public but rejected by most paleoanthropologists.

The idea that a distant companion star to the Sun periodically disturbs the Oort Cloud and triggers mass extinction events captivated astronomers in the 1980s but has never been confirmed.

The proposal that self-replicating RNA preceded DNA and proteins as the first life molecule is the leading origin-of-life theory, yet experiments have struggled to demonstrate spontaneous RNA formation under prebiotic conditions.

Despite decades of elegant mathematics, string theory's requirement of extra dimensions and its lack of testable predictions have led critics to question whether it qualifies as science at all.

The hypothesis that life on Earth was seeded by microorganisms from space, championed by Fred Hoyle and Chandra Wickramasinghe, challenges conventional models of abiogenesis.

Stephen Jay Gould and Niles Eldredge's 1972 model proposing that evolution occurs in rapid bursts separated by long periods of stasis sparked decades of debate among evolutionary biologists.

James Lovelock's idea that Earth's biosphere functions as a self-regulating system was dismissed as pseudoscience by many but has since influenced mainstream Earth system science.

Fleischmann and Pons's 1989 claim of achieving nuclear fusion at room temperature caused a global sensation before widespread failure to replicate relegated it to the scientific fringe.

Fred Hoyle's model of a universe with no beginning that continuously creates matter was a serious rival to the Big Bang until cosmic microwave background radiation was detected in 1965.

Elaine Morgan's proposal that human ancestors went through a semi-aquatic phase to explain bipedalism, hairlessness, and subcutaneous fat remains popular with the public but rejected by most paleoanthropologists.

The idea that a distant companion star to the Sun periodically disturbs the Oort Cloud and triggers mass extinction events captivated astronomers in the 1980s but has never been confirmed.

The proposal that self-replicating RNA preceded DNA and proteins as the first life molecule is the leading origin-of-life theory, yet experiments have struggled to demonstrate spontaneous RNA formation under prebiotic conditions.