Myth: The Great Wall of China is the only man-made structure visible from space with the naked eye. Fact: The Great Wall is not visible from low Earth orbit (where the International Space Station orbits) without magnification. It is too narrow (about 30 feet / 9 meters wide) and blends with the surrounding landscape. Astronauts have confirmed this. Why is this a myth?

Myth: Astronauts float in space because there is no gravity. Fact: Gravity is present in space. The International Space Station (ISS) orbits Earth at about 250 miles (400 km) altitude, where gravity is about 90% as strong as on Earth's surface. Astronauts float because they are in free fall – they are falling toward Earth at the same rate as the ISS, creating a feeling of weightlessness. Why do astronauts float on the ISS?

Myth: There is a "dark side of the Moon" that never receives sunlight. Fact: The Moon is tidally locked to Earth, meaning the same side always faces Earth (the near side). The far side (often called the "dark side") does receive sunlight – it experiences day and night just like the near side. The term "dark side" refers to the fact that it was unknown (dark as in unknown), not that it lacks sunlight. Which side of the Moon always faces Earth?

Myth: The Sun is a giant ball of fire (combustion). Fact: The Sun produces energy through nuclear fusion, not combustion (burning). In the Sun's core, hydrogen atoms fuse into helium, releasing enormous amounts of energy (light and heat). Fusion requires temperatures of about 15 million°C (27 million°F). How does the Sun produce energy?

Myth: Polaris (the North Star) is the brightest star in the night sky. Fact: Polaris is not the brightest star. Sirius (the "Dog Star") is the brightest star in the night sky (about 25 times brighter than Polaris). Polaris is notable because it is almost directly above the North Pole, so it appears stationary while other stars appear to rotate around it. Which star is the brightest in the night sky?

Myth: Seasons are caused by Earth's distance from the Sun. Fact: Seasons are caused by Earth's tilt (about 23.5 degrees) on its axis. When the Northern Hemisphere is tilted toward the Sun, it receives more direct sunlight (summer). When tilted away, it receives less direct sunlight (winter). Earth's distance from the Sun varies slightly, but it is not the cause of seasons. What causes Earth's seasons?

Myth: The Moon has no gravity. Fact: The Moon does have gravity – about 1/6 of Earth's gravity (1.62 m/s² vs Earth's 9.8 m/s²). This is why astronauts could jump higher and why the Moon has a faint atmosphere (exosphere). What is the acceleration due to gravity on the Moon compared to Earth?

Myth: Black holes suck in everything like a vacuum cleaner. Fact: Black holes have intense gravity, but they do not "suck" matter. Objects can orbit a black hole just like they orbit a star. If the Sun were replaced by a black hole of the same mass, Earth's orbit would remain unchanged (it would just get dark and cold). What happens if an object gets too close to a black hole?

Myth: You can hear sounds in space (like explosions). Fact: Sound requires a medium (solid, liquid, or gas) to travel. Space is a near-vacuum (very few particles), so sound cannot travel. In movies, explosions are shown with sound for dramatic effect, but in reality, space is silent. Can you hear sound in space?

Myth: If you went into space without a spacesuit, you would freeze instantly. Fact: Space is cold (about -270°C / -454°F), but heat transfer in a vacuum is slow (only by radiation). The bigger danger is lack of oxygen (you would lose consciousness in about 15 seconds). You would not freeze instantly; you would die from asphyxiation first. What is the main danger of being in space without a spacesuit?