What causes stars to twinkle? The turbulent motion of the atmosphere, caused by wind and daily temperature changes.
The atmosphere is the thin blanket of air and gases that surrounds Earth. It’s great for breathing, but the atmosphere is bad news for astronomers, since it is full of dust, pollution, clouds, and other visual obstacles. Astronomers first tried to rise above the problem by building observatories on mountains, where the air is thinner. They also mounted telescopes on balloons and airplanes. These things helped somewhat.
Then, in 1957, the first human-made satellite reached space. This finally gave astronomers an unobstructed view, and space telescopes began to scan the skies.