Here's why:

* Galileo's focus: Galileo was primarily interested in the motion of the celestial bodies like planets and moons. He focused on understanding the solar system and its structure, not the movement of plants.

* Heliocentric theory: Galileo was a strong advocate for the heliocentric model of the solar system (with the Sun at the center) as proposed by Nicolaus Copernicus. However, this theory focused on the orbits of planets around the sun, not plants.

* Plant growth: Galileo's observations and theories related to astronomy and physics, not botany. He was not involved in studying plant growth or movement.

The idea that plants revolve around the sun is not a scientific theory and is not supported by evidence.