Space Basics

 

1. Space has no sound. Because space is a vacuum with almost no molecules, sound waves cannot travel.
2. Space is extremely cold. The average temperature in deep space is about −270°C (−454°F).
3. Space begins roughly 100 km above Earth. This boundary is called the Kármán line.
4. Space is nearly empty. Even the emptiest areas between galaxies still contain about one atom per cubic meter.

 

Our Solar System

 

1. The Sun contains over 99% of the solar system’s mass.
2. The Sun is an average-sized star, yet about one million Earths could fit inside it.
3. Mercury is the fastest planet, orbiting the Sun at about 107,000 miles per hour.
4. A day on Venus is longer than its year. It takes 243 Earth days to rotate but 225 days to orbit the Sun.
5. Venus is the hottest planet, with temperatures around 850°F (450°C).
6. Uranus rotates on its side, making its seasons very unusual.
7. Mercury and Venus are the only planets without moons.
8. Jupiter’s Great Red Spot is a massive storm that has been raging for over 400 years.
9. Saturn is less dense than water, meaning it could theoretically float in a giant ocean.
10. Neptune has the fastest winds in the solar system, reaching 1,600 mph (2,600 km/h).

 

Moons, Planets, and Surfaces

 

1. Astronaut footprints on the Moon can last millions of years because there is no wind or water to erase them.
2. Mars has the tallest volcano in the solar system, Olympus Mons, nearly three times taller than Mount Everest.
3. Mars also has the largest canyon, Valles Marineris, which stretches 3,000 miles.
4. Sunsets on Mars appear blue, the opposite of Earth’s red sunsets.
5. Gas giants like Jupiter and Saturn have no solid surface, so you couldn’t stand on them.

 

Stars, Galaxies, and the Universe

 

1. The universe is about 13.8 billion years old and has been expanding since the Big Bang.
2. The Milky Way galaxy contains about 100–400 billion stars.
3. There are roughly 2 trillion galaxies in the observable universe.
4. There are more stars in the universe than grains of sand on all Earth’s beaches.
5. Stars are born in nebulae, giant clouds of gas and dust called stellar nurseries.
6. The Milky Way is about 105,700 light-years wide.
7. Our galaxy will collide with the Andromeda galaxy in several billion years.

 

Extreme Space Objects

 

1. Neutron stars are incredibly dense. A teaspoon of one could weigh trillions of kilograms.
2. Black holes have gravity so strong that even light cannot escape them.
3. Falling into a black hole could stretch you like spaghetti, a process called spaghettification.
4. Some black holes emit pressure waves that scientists have translated into sound.

 

Space Events & Objects

 

1. Shooting stars aren’t stars—they are tiny meteors burning up in Earth’s atmosphere.
2. Comets are icy leftovers from the formation of the solar system about 4.5 billion years ago.
3. Asteroids about the size of a car enter Earth’s atmosphere roughly once a year, but they burn up before reaching the ground.
4. The asteroid Vesta has a mountain about 22 km tall, nearly three times the height of Mount Everest.

 

Humans in Space

 

1. The International Space Station (ISS) is about the size of a soccer field and orbits Earth every 90 minutes.
2. Astronauts can grow up to about 2 inches taller in space because their spines stretch in microgravity.
3. Space smells unusual, often described by astronauts as seared steak or hot metal.
4. Over 600 people have traveled to space.
5. Dogs were sent to space before humans.

 

Space Environment

 

1. There are hundreds of thousands of pieces of space debris orbiting Earth, including old satellites and rocket fragments.
2. If two clean pieces of metal touch in space, they can stick together permanently due to a process called cold welding.
3. Suction cups do not work in space because there is no air pressure.

 

Strange and Surprising Space Facts

 

1. Scientists discovered a massive water vapor cloud in space containing 140 trillion times the water in Earth’s oceans.
2. Diamonds may rain on Neptune and Uranus because of extreme pressure and temperature.
3. Saturn currently has more than 250 known moons.
4. Pluto’s moon Charon is so large that Pluto and Charon orbit each other like a double system.
5. Only about 5% of the universe is visible matter—the rest is dark matter and dark energy.