Why was it easier to break the sound barrier the first time at a high altitude?
Aircraft can fly faster at high altitude.
The air is more dense at a high altitude.
The air temperature at a high altitude is lower.
Air particles at a high altitude are more elastic.
The correct answer is that the air density is lower at high altitudes. The sound barrier is essentially a wall of compressed air that builds up in front of an object as it approaches the speed of sound. At lower altitudes, the air is denser, so it takes more energy to break through this wall of compressed air. However, at higher altitudes where the air is less dense, there are fewer air molecules to push aside and less resistance to overcome. This allows the aircraft to reach and exceed the speed of sound more easily. The temperature and elasticity of the air do play a role, but the air density is the most significant factor.
