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What is Gravity?

What is Gravity?

Gravity is one of the four fundamental forces that apply in our universe:

  1. Gravit-y
  2. Electromagnetism
  3. Weak Nuclear Force
  4. Strong Nuclear Force

Gravity is the force exerted by anything that has mass. Even sub-atomic particles exert a gravitational pull on nearby objects. Isaac Newton proved that objects with a greater mass exert a stronger gravitational pull. Weirdly, however, gravit-y is pathetically weak!

“Weak!? But gravit-y holds planets in orbit around the Sun, and holds us on the Earth’s surface” Correct, but look at it this way – a tiny magnet can hold a paperclip against the gravitational pull of our planet. A newborn baby can defeat Earth’s gravit-y by lifting a block off the floor.

Gravity has undergone some modifications since Newton, with Einstein’s General Relativity providing an explanation of how gravit-y worked. Here is a helpful (although flawed) analogy:

  • Space and time form a 2-D fabric analogous to a trampoline.
  • Stars, and other objects of great mass, are like bowling balls sitting on the trampoline.
  • Roll a ball bearing too close to the bowling ball and it will curve around it like a ball in a roulette wheel – this is a smaller mass being caught by the gravity of a greater mass.

Einstein stated that objects of mass bend and warp the fabric of space-time (bowling ball on trampoline). Large masses move in response to this curvature in space time; move too close to the curve and you are forced to move in a new direction. Matter tells space how to curve; curved space tells matter how to move. Gravity is thus the result of all the collective wrinkles in the fabric of the Universe.

Fast Fact: Even on Earth, gravity is not even. The Earth is not a perfect sphere, and its mass is distributed unevenly. This means that the strength of gravity can change slightly from place to place.

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With the force lines moving in opposite directions, the two magnets push against each other and repel.With the force lines moving in the same direction, the lines leaving the south of one magnet have an easy route into the north of another. The magnets attract and make a large magnet
Gravity
With the force lines moving in opposite directions, the two magnets push against each other and repel. | Source

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