The Armstrong Limit: Where Your Blood Would Boil!

The Armstrong limit is like an invisible ceiling way, way up in the sky. If you go above this ceiling, the air is so thin and the pressure is so low that water starts to boil at the same temperature as your body! This means your spit, your tears, and even the water inside you would start to bubble. It's a very dangerous place to be without special protection, like a spacesuit!

A brave pilot named Harry George Armstrong was the first to really understand this strange effect. He was curious about what happens to people at super high altitudes. He studied how the low pressure affected the human body. Because of his important discoveries, this special altitude is named after him. It's like getting your name on a star!

This limit is super important for pilots and astronauts. Airplanes usually fly way below the Armstrong limit because it's safe. If a plane accidentally went too high, everyone inside would be in big trouble very quickly. Astronauts going to space need special suits that keep them safe from this boiling effect and the lack of air.

The Armstrong limit is about 11 miles (18 kilometers) up in the sky. That's higher than most airplanes fly! To imagine how high, think about a really tall skyscraper. This limit is much, much higher than even the tallest building. It's so high that the air pressure is less than 1% of the air pressure we feel down here on the ground.