Gravity is one of the fundamental forces in nature. It is the force of mutual attraction between any two objects that have mass. The more massive an object is, the stronger its gravitational pull. On Earth, we experience gravity as the force that pulls objects toward the center of our planet, which is why things fall down when dropped.
Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force proportional to the product of their masses and inversely proportional to the square of the distance between them. This means that doubling the mass doubles the force, but doubling the distance reduces the force to one-fourth.
On Earth, gravity gives all objects a constant acceleration of 9.8 meters per second squared toward the center of the planet. This means that regardless of their mass, all objects fall at the same rate in a vacuum. A feather and a hammer would hit the ground simultaneously if air resistance is removed. Your weight is simply your mass multiplied by this gravitational acceleration.
Gravity is not limited to Earth. It operates throughout the entire universe, keeping celestial bodies in motion. The Moon orbits Earth due to Earth's gravitational pull, while Earth orbits the Sun because of the Sun's much stronger gravity. Even our entire solar system orbits around the center of the Milky Way galaxy. Without gravity, planets would fly off into space in straight lines.
Gravity has countless practical applications that affect our daily lives. GPS satellites rely on precise gravitational calculations to provide accurate positioning. Weather systems are driven by gravitational effects on air masses. Ocean tides result from the Moon's gravitational pull. Space missions use gravity assists to reach distant planets. Even hydroelectric power depends on gravity pulling water downward. Understanding gravity is essential for modern technology and exploration.