Here's why:
* Newton's Law of Universal Gravitation: The force of gravity between two objects depends on their masses and the distance between their centers. The equation is:
* F = G * (m1 * m2) / r²
* F = force of gravity
* G = gravitational constant
* m1 and m2 = masses of the two objects
* r = distance between their centers
* Orbit is a balance: Earth orbiting the Sun is a dynamic equilibrium. The Earth's orbital velocity creates a centrifugal force that balances out the Sun's gravitational pull. The distance between the Earth and Sun remains relatively constant, as does the force of gravity between them.
What changes in orbit:
* Direction of force: While the magnitude of the gravitational force remains constant, the *direction* of the force constantly changes as Earth orbits the Sun. This is what keeps Earth in its curved path.
* Orbital velocity: Earth's orbital speed changes slightly depending on its position in its elliptical orbit. However, this change in velocity is a consequence of the constant gravitational force, not a change in the force itself.
In summary: Placing Earth in orbit doesn't affect the fundamental force of gravity between it and the Sun. It's the balance of that force with the Earth's orbital motion that creates the conditions for a stable orbit.
