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11,491 facts. Click any fact to see its full page.
All 11,491
📜 History 1,991
🔬 Science 1,964
🐾 Animals 1,525
🚀 Space 977
🧠 Psychology 893
🌿 Nature 759
💻 Technology 735
🌍 Geography 599
🎭 Culture 581
🫀 Human Body 572
🌊 Ocean 373
💬 Language 245
🍕 Food 199
✨ General 68
✨ Dinosaur 10
Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union.
The largest volcano in the solar system, Olympus Mons on Mars, is 600 km wide at its base.
Time passes slightly faster at your head than at your feet due to Earth's gravitational gradient — relativity at work.
Mars's two moons, Phobos and Deimos, are thought to be captured asteroids.
The first telescope was invented around 1608, and Galileo turned one on the sky in 1609, discovering Jupiter's moons.
There are estimated to be over 100 billion planets in the Milky Way alone.
The Hubble constant — the rate of universe's expansion — has been measured by different methods and doesn't quite agree, puzzling cosmologists.
Pulsars are so regular in their rotation that early researchers thought they might be alien signals — they were initially called LGM-1.
The Moon's far side was not seen by humans until Soviet probe Luna 3 photographed it in 1959.
The cosmic web is a vast structure of filaments of dark matter connecting galaxy clusters across the universe.
Betelgeuse, the red supergiant in Orion, is expected to go supernova sometime in the next 100,000 years.
The Milky Way's supermassive black hole, Sagittarius A*, has a mass 4 million times that of the Sun.
Space has no definitive boundary — the Kármán line at 100 km altitude is a conventional definition.
The Big Rip is a theoretical scenario where dark energy eventually tears apart all matter in the universe.
The speed of light in glass or water is slower than in a vacuum — this is how lenses and prisms work.
Stars in globular clusters are so densely packed that planetary systems are unlikely to form stably within them.
The Voyager probes carry golden records with sounds and images of Earth as a message to potential extraterrestrial finders.
Cosmic inflation theory suggests the universe expanded faster than light in the first fraction of a second after the Big Bang.
The longest eclipse of the Sun visible from Earth's surface lasts about 7 minutes and 32 seconds.
The dwarf planet Ceres, in the asteroid belt, has been found to contain water ice and organic compounds.
A magnetar — a type of neutron star — has a magnetic field quadrillions of times stronger than Earth's.
The first images of a black hole were captured in 2019 by the Event Horizon Telescope collaboration.
The Fermi Paradox asks why, given the vast number of potentially habitable planets, we've detected no signs of other civilizations.
The Apollo astronauts left retroreflectors on the Moon — scientists still bounce lasers off them today.
Quasars, powered by supermassive black holes, can outshine entire galaxies by a factor of thousands.
Neutron stars pack 1.4 times the mass of the Sun into a sphere about 20 km across.
The Sun's outer atmosphere, the corona, is hundreds of times hotter than its visible surface for reasons not fully understood.
Sound waves in the Coma Galaxy Cluster produce a note 57 octaves below middle C, too low for humans to hear.
The Oort Cloud, a vast reservoir of comets at the edge of the solar system, has never been directly observed.
White dwarf stars are remnants of sun-like stars that have exhausted their nuclear fuel and shed their outer layers.
The Kepler Space Telescope discovered over 2,600 confirmed exoplanets during its mission.
There are rogue black holes — stellar-mass black holes ejected from galaxies and wandering through space.
Europa's subsurface ocean is estimated to contain twice as much water as all of Earth's oceans combined.
The first human in space was Soviet cosmonaut Yuri Gagarin on April 12, 1961.
Cosmic rays — high-energy particles from space — pass through your body at a rate of about one per second.
The James Webb Space Telescope can detect heat signatures equivalent to a bumblebee at the distance of the Moon.
The Moon's gravity is responsible for tidal locking — the same side always faces Earth.
The universe is not only expanding but accelerating in its expansion, driven by a force called dark energy.
Saturn is so light relative to its volume that it would float in water if a large enough ocean existed.
There are more galaxies in the observable universe than grains of sand on all of Earth's beaches.
The surface temperature on Venus reaches 465°C — hot enough to melt lead.
The geoduck clam can live over 150 years and is the largest burrowing clam in the world.
Starlings can form murmurations — synchronized aerial displays involving hundreds of thousands of birds.
The proboscis monkey of Borneo has a nose so large it has to push it aside to eat.
The Portuguese man o' war is not a jellyfish but a siphonophore — a colony of specialized organisms acting as one.
Fireflies communicate through bioluminescence, and each species has a unique flash pattern.
The largest land animal ever to have lived was the Patagotitan mayorum, a sauropod dinosaur weighing 70+ tons.
Chimpanzees have been observed making and using spears to hunt smaller primates.
A cockroach can survive a week without its head — it dies eventually from inability to drink water.
Toucans regulate body temperature by adjusting blood flow to their large bills.