Why the Earth Is a Sphere, Not a Disc
That the Earth is a sphere (more precisely, a slightly flattened sphere) can be verified yourself with several simple observations - you don't have to fly into space to check.
đź’¬ Mia asks Grandpa Theo
How do we even know this, if you can't fly into space yourself?
Take a ship slowly disappearing over the horizon: first the hull vanishes, and the mast tip disappears last. On a flat disc, the whole ship would just keep getting smaller, not disappear piece by piece.
Are there more proofs you can see yourself?
During a lunar eclipse, the Earth casts its shadow onto the moon - and that shadow is always round, no matter the angle. Only a sphere casts a round shadow from every direction.
Different constellations: travel far north or south and you see different stars in the sky - on a disc, everyone everywhere would see the same sky.
Going all the way around: you can keep flying in one direction (e.g. always east) and eventually arrive back at your starting point.
Photos from space: satellites and astronauts have photographed the round Earth thousands of times.
Strictly speaking, the Earth isn't a perfect sphere - it's slightly flattened at the poles and bulges a bit at the equator, which is called an oblate spheroid. But for everyday purposes, "sphere" is a perfectly good approximation.
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