The exhaust of a jet engine can make things blurry due to a phenomenon known as heat shimmer or exhaust blur. This effect occurs because the hot gases expelled from the jet engine cause variations in the refractive index of the air surrounding them.
When a jet engine operates, it releases a high-velocity stream of hot gases into the surrounding atmosphere. These gases have a different temperature and density than the ambient air, creating a gradient in the refractive index of the air. Light passing through this gradient experiences rapid changes in direction, leading to the blurring or distortion of objects seen through it.
The heat shimmer effect is similar to what you observe when looking at distant objects on a hot summer day, where the heated air near the ground causes the light to refract and create a blurry appearance. In the case of a jet engine, the high-temperature exhaust gases produce a similar effect, especially when viewed from certain angles.
This distortion can be more pronounced when viewing objects located close to the exhaust or when the exhaust gases pass through a boundary layer, such as when a jet is taking off or landing. Additionally, factors like humidity, air currents, and atmospheric conditions can influence the intensity of the heat shimmer effect.
It's worth noting that the extent of blurring caused by the jet engine exhaust can vary depending on the engine type, operating conditions, and the observer's position relative to the exhaust.