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Our atmosphere doesn't end in one spot: it thins out the higher you get, until there is almost no air left at all. For simplicity, scientists say that the atmosphere ends at the Kármán line, 100 km (62 miles) above sea level. That's where sky is said to become space, which is what people mean when they talk about 'the edge of space'. Beyond that line, there is not enough air to create drag.