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If you could drive a car straight up into the sky at highway speed, you would reach the edge of outer space in under an hour — the only thing protecting every living creature on Earth from the lethal
Space Daily • • science
Key Points:
- The Earth's atmosphere is an extremely thin layer, extending about 100 kilometres to the Kármán line, which marks the conventional boundary between the atmosphere and outer space, though this boundary is somewhat arbitrary and regulatory rather than physical.
- Approximately 99% of the atmosphere's mass is concentrated within the lowest 32 kilometres, with the breathable troposphere comprising about 12 kilometres and containing 80% of the atmosphere's mass.
- The atmosphere's thinness is starkly illustrated by scale: if Earth were the size of an apple, the atmosphere up to the Kármán line would be only about 0.6 millimetres thick, comparable to or thinner than apple skin.
- This thin atmospheric layer is crucial for life, providing breathable air, filtering harmful ultraviolet radiation via the ozone layer, burning up meteors, and shielding the surface from high-energy solar radiation.
