What Is the Gravitational Pull?

Gravitational pull is a powerful force in space.

Gravitational pull is the force that large bodies, like planets, exert over smaller objects. Gravity pulls thrown objects back to Earth, and it also keeps the moon on its orbit. Gravitational pull is a term used to describe this force, which has a number of implications in air and space travel. Sir Isaac Newton developed the Universal Law of Gravitation, which created an equation that can be used to figure out the gravitational pull of celestial bodies.

Gravity

Gravity is one of the basic forces to which everyone is accustomed; gravity is an almost unnoticed part of everyday life. The simple gravitational pull of the Earth is what causes a dropped or thrown item to fall back to the ground. Additionally, Earth's many satellites--both man-made and natural--are kept in their orbits by the force of gravity. Sir Isaac Newton is credited with discovering a method of figuring out how strong gravity is based on a number of factors, such as the size and mass of a celestial body.

Universal Law of Gravitation

The Universal Law of Gravitation is used to determine the strength of the gravitational pull exerted by a planet or star. The equation takes into account the masses of both objects being studied, the amount of separation between them, the gravitational force and the universal gravitational constant. This equation was used by Newton to postulate that an object moving around the Earth at the right velocity would constantly orbit the planet. Global Positioning Satellites and other man-made satellites rely on Newton's discovery for their design.

Solar Systems

Solar systems exist because of the gravitational pull exerted by a star. Dust, debris and other objects in space are pulled into orbit around the star and form planets through collisions. The Earth, which is roughly 4.5 billion years old, formed as a result of the gravitational pull of the star at the center of the solar system, the sun. The sun holds all of the planets in orbit around it due to the same principles that cause the moon to orbit around the Earth.

Considerations

Space missions rely on the knowledge of gravitational pull to successfully launch things like Voyager 1 and Voyager 2. Telescopes, satellites, the space stations and missions and all other extraterrestrial activity must take the gravitational pull exerted by Earth and other planets into account when planning missions, as the gravitational pull of a planet could knock a spacecraft off course. Additionally, Earth's gravity is a major factor in designing and building aircraft.

Effects

Newton's Universal Law of Gravitation played a major role in the development and understanding of Einstein's theory of relativity. According to Professor Bangalore Sathyaprakash of the School of Physics and Astronomy at Cardiff University, the theory of relativity had to be altered due to conflicts between what the Universal Law of Gravitation states and how Einstein had theorized relativity. The idea of general relativity arose as a result of these conflicting ideas.

References

• UTK: Sir Isaac Newton--The Law of Universal Gravitation
• Plus Magazine: How Does Gravity Work?

Resources

• Exploratorium: Your Weight on Other Worlds