100 Facts About Space

100 Facts About Space

1. Our Solar System (1–10)

The Solar System formed about 4.6 billion years ago.
It consists of 8 planets, over 200 moons, and millions of asteroids and comets.
The Sun contains 99.86% of the Solar System’s total mass.
Mercury is the smallest planet and closest to the Sun.
Venus is the hottest planet, with surface temperatures around 475°C (900°F).
Earth is the only known planet with life.
Mars once had rivers and lakes of liquid water.
Jupiter, the largest planet, could fit 1,300 Earths inside it.
Saturn’s rings are made mostly of ice and dust.
Neptune has the fastest winds in the Solar System — over 2,000 km/h (1,200 mph).

2. Moons & Small Bodies (11–20)

Earth’s Moon is moving 3.8 cm away from us every year.
Ganymede (a moon of Jupiter) is the largest moon in the Solar System.
Titan (Saturn’s moon) has lakes of liquid methane and a thick atmosphere.
Europa (Jupiter’s moon) may have a subsurface ocean with potential life.
Enceladus sprays water vapor into space from ocean vents.
Pluto is now classified as a dwarf planet.
Ceres, in the asteroid belt, contains frozen water beneath its surface.
The Kuiper Belt lies beyond Neptune and contains icy bodies like Eris and Makemake.
The Oort Cloud may mark the edge of the Sun’s gravitational influence.
‘Oumuamua was the first known interstellar object to pass through our Solar System.

3. The Sun (21–30)

The Sun is a G-type main-sequence star about 4.6 billion years old.
Its surface temperature is around 5,500°C (10,000°F).
Every second, it converts 600 million tons of hydrogen into helium.
The Sun’s energy reaches Earth in about 8 minutes and 20 seconds.
Solar flares release as much energy as millions of nuclear bombs.
The solar wind creates auroras on Earth.
The Sun’s magnetic field flips every 11 years.
One day, the Sun will become a red giant, swallowing Mercury and Venus.
Afterward, it will shrink into a white dwarf.
The Sun will shine for another ~5 billion years before dying.

4. Stars & Constellations (31–40)

Stars are born in nebulae — clouds of gas and dust.
The closest star to Earth (besides the Sun) is Proxima Centauri, 4.24 light-years away.
Stars range from red dwarfs to blue giants.
Betelgeuse in Orion is a red supergiant nearing the end of its life.
Sirius, the Dog Star, is the brightest star in the night sky.
Neutron stars are the densest objects known — a teaspoon would weigh billions of tons.
Some stars rotate hundreds of times per second (pulsars).
Binary star systems are common — many stars have companions.
Constellations are patterns humans created to map the sky.
There are 88 officially recognized constellations.

5. Black Holes & Extreme Objects (41–50)

Black holes form when massive stars collapse.
Their gravity is so strong that not even light can escape.
The boundary beyond which nothing escapes is the event horizon.
Sagittarius A* is the supermassive black hole at our galaxy’s center.
The first black hole image was captured in 2019 (M87*).
Hawking radiation suggests black holes slowly evaporate.
The largest known black hole, TON 618, has ~66 billion solar masses.
Wormholes, a theoretical concept, could connect distant parts of space.
Quasars are galaxies powered by active black holes.
Neutron star mergers create gravitational waves and heavy elements like gold.

6. Galaxies & the Universe (51–60)

The Milky Way is a barred spiral galaxy about 100,000 light-years wide.
It contains 100–400 billion stars.
The Andromeda Galaxy is our nearest large neighbor, 2.5 million light-years away.
The Milky Way and Andromeda will collide in about 4.5 billion years.
There are at least 2 trillion galaxies in the observable universe.
The universe is 13.8 billion years old.
The Big Bang created space and time itself.
The cosmic microwave background is the leftover radiation from the Big Bang.
The universe is expanding — and the expansion is accelerating.
Dark energy drives this acceleration, making up about 68% of the universe.

7. Exoplanets & Other Worlds (61–70)

Scientists have discovered over 5,500 confirmed exoplanets (2025).
Hot Jupiters orbit very close to their stars.
Super-Earths are rocky planets larger than Earth.
The TRAPPIST-1 system has seven Earth-sized planets.
TOI-700 d is one of the best-known potentially habitable worlds.
Some exoplanets have iron rain or diamond interiors.
Rogue planets float freely through space without stars.
JWST can detect exoplanet atmospheres through infrared light.
Kepler and TESS space telescopes revolutionized exoplanet discovery.
The habitable zone is the region where liquid water can exist.

8. Cosmic Phenomena (71–80)

Comets are icy bodies that develop tails when near the Sun.
Asteroids are rocky remnants from the early Solar System.
Meteor showers occur when Earth passes through comet debris.
Auroras occur when solar particles collide with Earth’s atmosphere.
Gamma-ray bursts are the most energetic explosions in the universe.
Fast radio bursts are mysterious millisecond-long signals from deep space.
Gravitational waves ripple space-time and were first detected in 2015.
Dark matter makes up 27% of the universe’s mass-energy.
Cosmic rays constantly bombard Earth from outer space.
Time dilation occurs near massive objects or at near-light speeds.

9. Space Exploration (81–90)

Sputnik 1 (1957) was the first artificial satellite.
Yuri Gagarin became the first human in space in 1961.
Apollo 11 landed humans on the Moon in 1969.
Neil Armstrong was the first person to walk on the Moon.
Voyager 1 is the farthest human-made object, over 24 billion km away.
The International Space Station (ISS) orbits Earth every 90 minutes.
Mars rovers like Curiosity and Perseverance explore the Red Planet.
James Webb Space Telescope (JWST) studies the early universe.
Artemis missions aim to return humans to the Moon.
SpaceX and Blue Origin are developing reusable rockets for future exploration.

10. Mysteries & the Future (91–100)

The Fermi Paradox asks why we haven’t detected alien life yet.
SETI listens for signals from extraterrestrial civilizations.
Dyson spheres could capture a star’s entire energy output.
Terraforming Mars might make it habitable one day.
Artificial gravity is still theoretical in spacecraft.
Light sails could allow interstellar travel using starlight.
Cryosleep is a proposed way for humans to endure long space trips.
Time travel is possible in theory via relativity, but not practically.
Humans may one day colonize Mars or moons like Titan.
Space remains 95% unexplored — our greatest frontier.

In Summary

Space is vast, mysterious, and full of wonders — from the smallest particles to the largest galaxies. Every discovery reveals how little we know, reminding us that exploration has only just begun.