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Truth Classification

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Capsule of the Day

DebunkedThe PolygraphThe instrument popularly called a lie detector, which records breathing, blood pressure, pulse and skin conductance dur…

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The library

Capsules

1,028 capsules, each one classified by the strength of its evidence.

All1,028Fact599Proven130Theory89Hypothesis71Contested90Debunked48
geography236biology88physics67history54medicine45astronomy33psychology26mathematics26chemistry20engineering20astrophysics19neuroscience19anthropology18art18

Trending now

Most recent activity

Factgeography

Flin Flon

Flin Flon is a mining city on the Manitoba and Saskatchewan boundary, about 630 kilometres northwest of Winnipeg, built directly on the rock of the Canadian Shield. It is one of…

by Capsule · Aug 7, 2026
Factbiology

Seahorse

Seahorses are small marine fish of the genus Hippocampus, around fifty species, distinguished by an upright posture, a prehensile tail, a tubular snout, and a reproductive…

by Capsule · Aug 7, 2026
Factagriculture

Livestock

Domesticated animals kept for food, fibre, labour and other products. Livestock made agriculture viable on land that grows no crops, and they are now among the largest single…

by Capsule · Aug 5, 2026
Fact

Browse all

Showing 761 to 780 of 1,028

NewestMost votedA to Z
astronomy
Fact· Historical

Carl Sagan

Carl Sagan (1934 to 1996) was an American astronomer and science communicator who did more than almost anyone to bring the wonder of the cosmos to…

byCapsule
epidemiology

Sanitation

The safe management of human waste. It has saved more lives than any medical treatment, it is the least discussed of the major public health measures, and roughly a fifth of the…

by Capsule · Aug 5, 2026
Factbiology

Common Raven

The common raven, Corvus corax, is the largest songbird in the world and among the most widely distributed birds on Earth, occupying the whole northern hemisphere from high Arctic…

by Capsule · Aug 7, 2026
Factgeography

Winkler

Winkler is the fourth-largest city in Manitoba, in the Pembina Valley about twenty kilometres north of the United States border, with 13,745 residents at the 2021 census. Like…

by Capsule · Aug 7, 2026
Fact· Empirical

Seahorse

Seahorses are small marine fish of the genus Hippocampus, around fifty species, distinguished by an upright posture, a prehensile tail, a tubular…

byCapsule0 votes0 reviewsAug 7, 2026
Fact

Livestock

Domesticated animals kept for food, fibre, labour and other products. Livestock made agriculture viable on land that grows no crops, and they are now…

byCapsule0 votes0 reviewsAug 5, 2026

Also new

More from the last few days

medicine
Fact

Nursing

The care of the sick, injured and dependent. Nursing is the largest health profession by a wide margin, its outcomes are measurable and substantial,…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Chimpanzee

The chimpanzee, Pan troglodytes, is one of the two species of the genus Pan and, with the bonobo, the closest living relative of human beings. It is…

byCapsule0 votes0 reviews
nutrition
Fact

Salt

Sodium chloride. It is physiologically essential, it was the only reliable food preservative for most of history, and its scarcity relative to demand…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Ant

Ants are eusocial insects of the family Formicidae, with over 14,000 described species and an estimated global population around twenty quadrillion…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Platypus

The platypus, Ornithorhynchus anatinus, is a semiaquatic egg-laying mammal of eastern Australia. It lays eggs, produces milk without nipples, detects…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Albatross

Albatrosses are large seabirds of the family Diomedeidae, with the longest wingspans of any living bird and a way of flying that costs them almost…

byCapsule0 votes0 reviews
economics
Fact

Accounting

The systematic recording and reporting of financial activity. Double-entry bookkeeping is among the more consequential inventions in the history of…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Spider

Spiders are arachnids of the order Araneae, with more than 50,000 described species. All of them produce silk, nearly all of them are venomous, and…

byCapsule0 votes0 reviews

On this day

A birth or event with an anniversary today

history
Fact· Empirical

Statue of Liberty

The Statue of Liberty is a colossal copper statue on an island in New York Harbor, one of the most famous monuments in the United States and a…

byCapsule0 votes0 reviews

Settled science

Verified facts and proven results

See all
biology
Fact· Empirical

Penguin

Penguins are flightless seabirds of the southern hemisphere, around eighteen species, which gave up flight in the air for flight underwater. They are…

byCapsule0 votes0 reviews
history
Fact· Historical

French Revolution

The French Revolution (1789–1799) was a period of radical political and social upheaval in France that ended the Bourbon monarchy, abolished feudal…

byCapsule0 votes0 reviews
agriculture
Fact

Nitrogen Cycling in Prairie Soils of the Canadian Prairies

Nitrogen cycling in Prairie soils is a well-documented biological and chemical process that determines agricultural productivity across Manitoba,…

byCapsule0 votes0 reviews
engineering
Proven

Arc Flash Hazard Mitigation in Industrial Electrical Systems

An arc flash is a high-energy electrical fault that produces an explosive release of heat, light, and pressure when a phase-to-phase or…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Great White Shark

The great white shark, Carcharodon carcharias, is the largest predatory fish, reaching about six metres. It is warm-blooded in a limited and…

byCapsule0 votes0 reviews
astronomy
Fact· Empirical

The Solar System

The Solar System is the Sun and everything bound to it by gravity: eight planets, several dwarf planets, scores of moons, and countless smaller…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Elephant

Elephants are the largest living land animals, and there are three species rather than the two most references still give. They have the longest…

byCapsule0 votes0 reviews
biology
Fact

DNA (Deoxyribonucleic Acid)

Deoxyribonucleic acid (DNA) is the molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of…

byCapsule0 votes0 reviews
agriculture
Fact

Traditional Yoruba Agricultural Practices in Southwestern Nigeria

The Yoruba people of southwestern Nigeria developed sophisticated agricultural systems over centuries that integrated intercropping, seasonal…

byCapsule0 votes0 reviews
history
Fact· Empirical

The Colosseum

The Colosseum is a giant amphitheatre in the centre of Rome, the largest ever built and one of the most recognisable monuments of the ancient world.…

byCapsule0 votes0 reviews
geology
Fact· Empirical

Volcano

A volcano is an opening in a planet's crust through which molten rock, gas, and ash erupt from the hot interior to the surface. On Earth they are…

byCapsule0 votes0 reviews
astronomy
Fact· Empirical

Black Hole

A black hole is a region of space where gravity is so intense that nothing, not even light, can escape once it passes a certain boundary. They are…

byCapsule0 votes0 reviews

Open questions

Hypotheses under investigation and ideas still debated

See all
history
Contested

The Bronze Age Collapse

The Bronze Age collapse was a sudden, widespread breakdown of civilizations around the eastern Mediterranean roughly 3,200 years ago. Within a few…

byCapsule0 votes0 reviews
biology
Contested

Are Viruses Alive?

Whether viruses count as living organisms is a question biologists have debated for over a century, and there is still no settled answer. Viruses sit…

byCapsule0 votes0 reviews
psychology
Contested

The Origin of Language

How human language first arose is one of the hardest questions in science. That we alone among animals possess full language is clear; when, how, and…

byCapsule0 votes0 reviews
physics
Contested

The Multiverse

The multiverse is the hypothesis that our universe is only one of many, perhaps even infinitely many, other universes. It is taken seriously by many…

byCapsule0 votes0 reviews
philosophy
Contested

Free Will

Free will is the question of whether people are truly free to choose their actions, or whether every choice is the inevitable product of prior…

byCapsule0 votes0 reviews
physics
Contested

Interpretations of Quantum Mechanics

Quantum mechanics is the most successful physical theory ever devised, predicting the behavior of atoms, light, and subatomic particles with…

byCapsule0 votes0 reviews
neuroscience
Contested

The Hard Problem of Consciousness

The hard problem of consciousness is the question of why and how physical processes in the brain give rise to subjective experience, the felt quality…

byCapsule0 votes0 reviews
biology
Contested

Are Animals Conscious?

Whether animals have conscious experiences, an inner life of feelings and awareness, is a deep and genuinely contested question. That many animals…

byCapsule0 votes0 reviews
psychology
Hypothesis

Social Media Use and Adolescent Depression: Causal Relationship Under Investigation

The proposition that social media use directly causes depression in adolescents remains under active scientific investigation. While correlational…

byCapsule0 votes0 reviews
astronomy
Hypothesis

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…

byCapsule0 votes0 reviews
psychology
Contested

Nature versus Nurture

The nature versus nurture debate asks how much of who we are, our intelligence, personality, talents, and behavior, comes from our genes, and how…

byCapsule0 votes0 reviews
astronomy
Contested

The Origin of the Moon

How the Moon came to be is a question that has fascinated and divided scientists for generations. While one explanation is now favoured, important…

byCapsule0 votes0 reviews

Debunked

Claims the evidence overturned

See all
music
Debunked

The Mozart Effect

The claim that listening to Mozart makes people, and especially babies, more intelligent. It came from one small study whose actual finding was far…

byCapsule0 votes0 reviews
history
Debunked

Astrology

Astrology is the belief that the positions of the Sun, Moon, planets, and stars influence human affairs and personalities, and that they can be used…

byCapsule0 votes0 reviews
physics
Debunked

The Luminiferous Aether

The luminiferous aether was a hypothetical substance once believed to fill all of space and to serve as the medium through which light waves…

byCapsule0 votes0 reviews
geology
Debunked

The Expanding Earth

The expanding Earth was a hypothesis, taken seriously by some scientists into the twentieth century, which claimed that the planet is steadily…

byCapsule0 votes0 reviews
astrophysics
Debunked

The Steady State Theory

The steady state theory was a model of the universe, popular in the mid twentieth century, which held that the universe has always looked roughly the…

byCapsule0 votes0 reviews
history
Debunked

Alchemy

Alchemy was an ancient and medieval practice that sought to transform base metals such as lead into gold, to discover a universal cure for disease,…

byCapsule0 votes0 reviews
science
Debunked

Cold Fusion at Room Temperature

The 1989 Fleischmann-Pons announcement claimed that palladium electrodes immersed in heavy water produced excess heat consistent with…

byCapsule0 votes0 reviews
medicine
Debunked

Miasma Theory

Miasma theory was the belief that diseases such as cholera and the plague were caused by "bad air," a poisonous vapor thought to rise from rotting…

byCapsule0 votes0 reviews
architecture
Debunked

The Golden Ratio in Art and Architecture

The golden ratio is a real and interesting number. The claim that it governs the Parthenon, the Great Pyramid, the Mona Lisa and the proportions of…

byCapsule0 votes0 reviews
geology
Debunked

The Hollow Earth

The hollow Earth was the idea that our planet is not solid but hollow, perhaps containing a habitable inner world, or even inner suns and…

byCapsule0 votes0 reviews
education
Debunked

Learning Styles

The idea that each person learns best through a particular sensory channel, and that teaching matched to that channel improves learning. It is…

byCapsule0 votes0 reviews
physics
Debunked

The Caloric Theory

The caloric theory was an explanation of heat, widely accepted into the early nineteenth century, which held that heat is an invisible, weightless…

byCapsule0 votes0 reviews

Theories explained

Well substantiated explanations of how things work

See all
earth science
Theory

The Greenhouse Effect

The greenhouse effect is the process by which certain gases in a planet's atmosphere trap heat, keeping the surface warmer than it would otherwise…

byCapsule0 votes0 reviews
biology
Theory· Scientific

Evolution by Natural Selection

Evolution by natural selection is the scientific theory that explains how the diversity of life arose and continues to change. It holds that…

byCapsule0 votes0 reviews
physics
Theory

Optics

Optics is the branch of physics that studies light: how it travels, how it interacts with matter, and how it can be controlled with lenses and…

byCapsule0 votes0 reviews
geology
Theory

Uniformitarianism

Uniformitarianism is the foundational principle of geology: that the same natural processes we observe today, such as erosion, sedimentation, and…

byCapsule0 votes0 reviews
astronomy
Theory· Scientific

The Big Bang

The Big Bang is the prevailing cosmological theory of how the universe began. It holds that the universe started about 13.8 billion years ago in an…

byCapsule0 votes0 reviews
physics
Theory

Dark Matter: The Leading Theoretical Framework for Missing Mass in the Universe

Dark matter is the leading theoretical framework proposed to explain gravitational effects observed in galaxies and galaxy clusters that cannot be…

byCapsule0 votes0 reviews
mathematics
Theory

Topology

Topology is the branch of mathematics that studies the properties of shapes that survive stretching, bending, and twisting, but not tearing or…

byCapsule0 votes0 reviews
computer science
Theory· Mathematical

Information Theory

Information theory is the mathematical study of how information is measured, stored, and communicated. It defines what information actually is in…

byCapsule0 votes0 reviews
science
Theory

The Gut-Brain Axis: Microbiome Influence on Mental Health

The gut-brain axis describes the bi-directional signalling between gut microbiota and the central nervous system via the vagus nerve, immune system,…

byCapsule0 votes0 reviews
medicine
Theory· Scientific

Germ Theory of Disease

The germ theory of disease is the scientific theory that many illnesses are caused by microorganisms, living agents too small to see, that invade the…

byCapsule0 votes0 reviews
physics
Theory· Scientific

General Relativity

General relativity is Albert Einstein's theory of gravity, published in 1915. It reimagines gravity not as a force pulling objects together but as…

byCapsule0 votes0 reviews
physics
Theory

Acoustics: The Science of Sound

Acoustics is the branch of physics that studies sound: how it is produced, how it travels as waves, and how it is heard. It bridges science and art,…

byCapsule0 votes0 reviews
0 votes0 reviews
history
Fact· Historical

Malcolm X

Malcolm X (1925 to 1965) was an American Muslim minister and human rights activist, one of the most influential and controversial figures of the…

byCapsule0 votes0 reviews
history
Fact· Historical

Mother Teresa

Mother Teresa (1910 to 1997) was a Catholic nun who devoted her life to caring for the poorest and the dying in India and around the world. Honoured…

byCapsule0 votes0 reviews
sport
Fact· Historical

Muhammad Ali

Muhammad Ali (1942 to 2016) was an American boxer and one of the most famous and influential sportspeople of the twentieth century. A three time…

byCapsule0 votes0 reviews
art
Fact· Historical

Ludwig van Beethoven

Ludwig van Beethoven (1770 to 1827) was a German composer and pianist, one of the most admired figures in the history of Western music. He bridged…

byCapsule0 votes0 reviews
art
Fact· Historical

Pablo Picasso

Pablo Picasso (1881 to 1973) was a Spanish painter and sculptor widely considered one of the most influential artists of the twentieth century.…

byCapsule0 votes0 reviews
mathematics
Fact· Historical

Alan Turing

Alan Turing (1912 to 1954) was a British mathematician and logician widely regarded as the father of computer science and artificial intelligence.…

byCapsule0 votes0 reviews
history
Fact· Historical

Mansa Musa

Mansa Musa (ruled around 1312 to 1337) was the ruler of the West African Empire of Mali at its height, and is often described as one of the…

byCapsule0 votes0 reviews
history
Fact· Historical

Rosa Parks

Rosa Parks (1913 to 2005) was an American civil rights activist whose refusal to give up her bus seat to a white passenger helped spark a landmark…

byCapsule0 votes0 reviews
philosophy
Fact· Historical

Confucius

Confucius (551 to 479 BC) was a Chinese philosopher and teacher whose ideas about ethics, family, and good government shaped Chinese civilization for…

byCapsule0 votes0 reviews
history
Fact· Historical

Napoleon Bonaparte

Napoleon Bonaparte (1769 to 1821) was a French military and political leader who rose during the French Revolution to become Emperor of the French…

byCapsule0 votes0 reviews
astrophysics
Fact· Historical

Stephen Hawking

Stephen Hawking (1942 to 2018) was a British theoretical physicist who became one of the most famous scientists of his time, renowned for his work on…

byCapsule0 votes0 reviews
art
Fact· Historical

Frida Kahlo

Frida Kahlo (1907 to 1954) was a Mexican painter known for her vivid, deeply personal self portraits and her use of Mexican folk traditions. Once…

byCapsule0 votes0 reviews
art
Fact· Historical

Wolfgang Amadeus Mozart

Wolfgang Amadeus Mozart (1756 to 1791) was an Austrian composer regarded as one of the greatest musical geniuses in history. A child prodigy who…

byCapsule0 votes0 reviews
philosophy
Fact· Historical

Aristotle

Aristotle (384 to 322 BC) was an ancient Greek philosopher and scientist whose work shaped Western thought for two thousand years. He wrote on an…

byCapsule0 votes0 reviews
history
Contested

The Origin of the Etruscans

The Etruscans were a sophisticated people who flourished in ancient Italy before Rome rose to power, leaving rich art and a language unlike any…

byCapsule0 votes0 reviews
astronomy
Contested

The Wow! Signal

The Wow! signal was a strong, unexplained radio signal detected in 1977 by a telescope scanning the sky for possible messages from other…

byCapsule0 votes0 reviews
physics
Contested

Ball Lightning

Ball lightning is a reported phenomenon in which a glowing, floating sphere of light appears, usually during thunderstorms. Many people claim to have…

byCapsule0 votes0 reviews
history
Contested

How the Pyramids Were Built

The Great Pyramids of Egypt are among the most astonishing structures ever built, yet exactly how the ancient Egyptians raised them, with millions of…

byCapsule0 votes0 reviews
astrophysics
Contested

The Hubble Tension

The Hubble tension is a genuine and growing puzzle in cosmology: two careful ways of measuring how fast the universe is expanding give answers that…

byCapsule0 votes0 reviews
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