🍎 GRAVITY: KEEPING US DOWN
PAGE 1 OF 5, EVERYTHING FALLS TOWARD THE CENTRE
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GRAVITY IS NOT JUST “DOWN”
Gravity is the mutual attraction between masses, Earth pulls you, but you also pull Earth by a tiny unmeasurable amount. “Down” means toward Earth's centre: Australians do not fall off because their floor pushes up with an equal and opposite contact force. Newton pictured gravity reaching through empty space; Einstein described it as mass curving spacetime so that free-fall paths curve, both models predict apples and moons with stunning accuracy for most engineering.
⚡ DID YOU KNOW?
At the International Space Station altitude, gravity is still about 90% as strong as on the ground, astronauts float because they are constantly falling around Earth in orbit.
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NEWTON
🍎 Legend of apple, real maths
🌙 Same law explains Moon orbit
🌙 Same law explains Moon orbit
EINSTEIN
🕳️ Mass curves spacetime
📡 GPS uses relativistic fixes
📡 GPS uses relativistic fixes