Because, we just notice, by looking up in the sky, that the gravitational theroy seems to work even on larger scales, e.g. attraction between galaxies.
Gravitational force is the attraction between two objects with mass. It is one of the fundamental forces in the universe and is responsible for the motion of planets, stars, and other celestial bodies.
Gravitational force can be measured using the equation F=G*(m1*m2)/d^2, where F is the force, G is the gravitational constant, m1 and m2 are the masses of the two objects, and d is the distance between them. It is typically measured in Newtons (N).
One of the most famous examples of evidence for gravitational force is the orbit of the planets around the sun. This demonstrates the gravitational pull of the sun on the planets. Other evidence includes the tides caused by the moon's gravitational pull on Earth, and the bending of light around massive objects like galaxies.
According to the equation F=G*(m1*m2)/d^2, distance has an inverse square relationship with gravitational force. This means that as the distance between two objects increases, the gravitational force between them decreases. For example, the force between Earth and the moon is stronger than the force between Earth and the sun due to their different distances.
Gravitational force plays a crucial role in keeping our solar system in balance and allowing life to exist on Earth. It also has practical applications, such as keeping satellites in orbit and allowing us to measure the mass of planets and stars. Additionally, it is the force that causes objects to fall to the ground, making it essential for activities like walking, driving, and sports.