Is Time Travel Possible?
Time travel, journeying into the past or the future, is a staple of science fiction, but is it actually possible? The surprising answer from physics…
Capsules
Results
Matching your filter
The Drake Equation
The Drake equation is a famous formula that estimates how many communicating alien civilizations might exist in our galaxy. It is less a precise…
The Aquatic Ape Hypothesis
The aquatic ape hypothesis is the controversial idea that human ancestors went through a phase of living partly in water, and that this shaped many…
Grand Unified Theory
A Grand Unified Theory is a hypothesized framework that would merge three of the fundamental forces of nature, the electromagnetic, weak, and strong…
Snowball Earth
Snowball Earth is the hypothesis that, on one or more occasions in the distant past, our planet froze over almost completely, with ice reaching from…
Cosmic Inflation
Cosmic inflation is the hypothesis that, in the first tiny fraction of a second after the Big Bang, the universe expanded at an almost unimaginable…
The Simulation Hypothesis
The simulation hypothesis is the proposal that the reality we experience might actually be an artificial simulation, such as an immensely…
Panspermia
Panspermia is the hypothesis that life exists throughout the universe and is spread between worlds by space dust, meteoroids, asteroids, and comets.…
The Gaia Hypothesis
The Gaia hypothesis proposes that life and its physical environment on Earth form a single, self regulating system that keeps the planet suitable for…
Planet Nine
Planet Nine is a hypothetical large planet proposed to exist in the far outer reaches of our Solar System, well beyond Neptune and Pluto. It has…
The Rare Earth Hypothesis
The Rare Earth hypothesis proposes that complex, multicellular life, of the kind found on Earth, is extremely rare in the universe, because it…
The Riemann Hypothesis
The Riemann hypothesis is the most famous unsolved problem in mathematics. Proposed by Bernhard Riemann in 1859, it makes a precise claim about the…
The Dyson Sphere
A Dyson sphere is a hypothetical megastructure that an extremely advanced civilization might build around a star to capture a large share of its…
Wormholes
A wormhole is a hypothetical tunnel through spacetime that could, in principle, connect two distant points in the universe, or even two different…
Abiogenesis: The Origin of Life
Abiogenesis is the natural process by which life is thought to have arisen from non living matter, such as simple chemical compounds. How life first…
Goldbach's Conjecture
Goldbach's conjecture is one of the oldest and simplest sounding unsolved problems in mathematics. It states that every even whole number greater…