Universal Law of Gravitation

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One of Sir Issac Newton’s biggest contributions to physics and the larger body of science was the universal law of gravitation. Without it we can’t explain the classical motion of objects on Earth or in space. We would not have gained the ability to fly or even go into space. The understanding of gravity is basically the beggining of understanding classical mechanics and physics.

The story of how Sir Isaac Newton has now become one of the great myths of science. Every grade schooler of suitable age would be able to tell you how Newton discovered gravity when an apple fell on his head from the tree he sat under. In truth scientist had been doing gravity experiments long before Newton. One such scientist was the famous Renaissance Astronomer Gallileo. His experiments determined that all objects fall towards the earth with the same acceleration and velocity regardless of their mass. The only difference is air resistance.

Sir Issac Newton took it a step further. He saw that gravity was not just a phenomenon found on Earth, but a fundamental force that helped hold the universe together. His state that gravity could exists between any to objects with mass and the relationships of gravity’s strength to both objects mass and distance of seperation were major steps for classical mechanics.

However there are still holes in the universaal law of gravitation. First we don’t know what gravity is. It is a question similar to whether light is a particle or a wave. The question is whether gravity has a particle like other fundamental forces in the standard model or is simple the shape geometry of space time near objects with mass. The reason for the debate is that at high energies the law of gravity doesn’t behave properly and give the expected values. One explanation is that physics uses to different types of theories that are not usually linked together well. Classical mechanics deals with the large scale movements of objects while quantum physics deals with motions on the atomic and subatomic level. Each of these different frames of reference have different rules so don’t always act the same. Gravity is on of the forces yet to fit neatly into both points of view.

We have written many articles about the Universal Law of Gravitation for Universe Today. Here’s an article about gravity constant, and here’s an article about what causes gravity.

If you’d like more info on the Universal Law of Gravitation, check out these articles from NASA’s Imagine the Universe! and Physics Classroom.

We’ve also recorded an entire episode of Astronomy Cast all about Gravity. Listen here, Episode 102: Gravity.

Reference:
http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html

Tagged as: gravity, universal gravitation, universal law of gravitation