# The most mind-blowing space facts

Real facts about the solar system and the universe, among the most repeated in popular science (NASA and astronomy sites). Vote for the one that surprises you most.

- 41 votes · 28 items
- Mar 24, 2025 · cientifica_bucaramanga
- https://even.best/en/l/390/the-most-mind-blowing-space-facts

## Top 20

1. **Moon footprints can last millions of years** (5 · ▲5 ▼0) — With no wind or water to erase them, the Apollo 11 footprints (1969) will stay there for an immensely long time.
2. **A year on Neptune lasts 165 Earth years** (5 · ▲5 ▼0) — Since its discovery in 1846 it has completed just one orbit of the Sun, in 2011.
3. **The Moon drifts about 3.8 cm away from Earth each year** (2 · ▲3 ▼1) — Measured with lasers bounced off the mirrors left by the Apollo missions.
4. **Sunlight takes about 8 minutes to reach us** (2 · ▲2 ▼0) — The Sun is about 150 million km away: we see it as it was 8 minutes and 20 seconds ago.
5. **Olympus Mons is the largest known volcano in the solar system** (2 · ▲2 ▼0) — It's on Mars and is about 22 km high, almost three times Everest.
6. **Astronauts grow taller in space** (2 · ▲2 ▼0) — Without gravity the spine stretches and they can gain a few centimetres, which they lose on returning.
7. **A neutron star is incredibly dense** (2 · ▲2 ▼0) — A teaspoon of its matter would weigh billions of tonnes on Earth.
8. **There are more stars in the universe than grains of sand on all Earth's beaches** (2 · ▲2 ▼0) — One of popular science's favourite comparisons, based on estimates of the stars in the observable universe.
9. **Saturn would float in water** (1 · ▲2 ▼1) — Its average density is about 0.69 g/cm³, lower than water's (1 g/cm³).
10. **More than a million Earths would fit inside the Sun** (1 · ▲1 ▼0) — Its diameter is about 109 times Earth's.
11. **Jupiter's Great Red Spot is a storm bigger than Earth** (1 · ▲1 ▼0) — It has been observed for at least 150 years, although it is shrinking.
12. **We always see the same side of the Moon** (1 · ▲1 ▼0) — It takes the same time to spin once as to orbit Earth (tidal locking).
13. **There is no sound in space** (1 · ▲1 ▼0) — Sound needs a medium such as air to travel; in a vacuum nothing can be heard.
14. **The Milky Way has hundreds of billions of stars** (1 · ▲1 ▼0) — Estimates range from 100 to 400 billion.
15. **The Milky Way and Andromeda are heading for a collision** (1 · ▲1 ▼0) — The two galaxies are approaching and could merge in about 4.5 billion years.
16. **The universe is about 13.8 billion years old** (1 · ▲1 ▼0) — That's the age calculated since the Big Bang from the cosmic microwave background.
17. **Mercury isn't the hottest planet: Venus is** (1 · ▲1 ▼0) — Its CO₂ atmosphere causes a runaway greenhouse effect: about 465 °C at the surface.
18. **From sunrise to sunrise, a day on Mercury lasts longer than its year** (1 · ▲1 ▼0) — Sunrise to sunrise takes about 176 Earth days, twice its 88-day year.
19. **Voyager 1 is the most distant human-made object** (0 · ▲0 ▼0) — Launched in 1977, it crossed into interstellar space in 2012 and is still sending data.
20. **The International Space Station circles Earth every 90 minutes** (0 · ▲0 ▼0) — It travels at about 28,000 km/h: its astronauts see around 16 sunrises a day.
21. **The Earth is not a perfect sphere** (0 · ▲0 ▼0) — It is flattened at the poles: the equatorial diameter is about 43 km greater than the polar one.
22. **Pluto is smaller than our Moon** (0 · ▲0 ▼0) — It is about 2,377 km in diameter, compared to 3,474 km for the Moon.
23. **Uranus turns on its side** (0 · ▲0 ▼0) — Its axis is tilted about 98 degrees, so it rolls around the Sun almost like a ball.
24. **There are earthquakes on the Moon** (0 · ▲0 ▼0) — The Apollo seismometers recorded "moonquakes," some lasting several minutes.
25. **The Sun has 99.8% of the mass of the solar system** (0 · ▲0 ▼0) — All the planets, moons and asteroids together add up to just the remaining 0.2%.
26. **A day on Mars lasts almost the same as on Earth** (0 · ▲0 ▼0) — The Martian sun lasts 24 hours and 39 minutes.
27. **There is a giant cloud of alcohol in the Milky Way** (0 · ▲0 ▼0) — The Sagittarius B2 cloud, near the center of the galaxy, contains enormous amounts of ethanol.
28. **On Venus a day is longer than a year** (-1 · ▲2 ▼3) — Venus takes about 243 Earth days to spin once and 225 to orbit the Sun. And it spins the opposite way to almost every other planet.

How is this ranking ordered? By people's votes: each ▲ adds a point and each ▼ takes one away. Anyone can vote and add what is missing.