Paste your essay in here…Nicholas Kim
Mr. Nguyen
8th Grade NGSS Physical Science
15 October 2017
What is Gravity and its Effect on Matter?
The main asteroid belt contains about one to two million asteroids that exceed one kilometer in length, and millions more that are much smaller, but what keeps these in orbit? The answer of course is gravity. Gravity is what keeps everything on Earth from rocketing into space, keeps the moon and Earth in orbit, and holds the universe in one piece. Likewise, how does gravity function, and how does it affect asteroids and other existing masses?
What is Gravity?
In the past, hundreds of scientists and philosophers have speculated and theorized what gravity is. However, only two of theories are generally accepted by most scientists: Sir Isaac Newton’s law of gravity, and Albert Einstein’s theory that is part of his theory of relativity and special relativity.
Newton’s Theory
Legend has it that Isaac Newton was resting under an orchard tree, when an apple fell out of the tree and hit him on the head, abruptly waking him. This caused Newton to wonder what had caused this apple to fall, and thus created his theory of gravity, along with his three laws of movement.
Gravity, as defined Newton, is a force of attraction between any substance that contains mass. In addition, the strength of gravity is determinedly two factors: the mass of the matter, and the distance between the center of the two matters. Fundamentally, this means that closer and bigger the objects are, the greater the force of gravity will act upon it.
Moreover, gravity is measured in the equation F=G[(m1 x m2)/r^2] N m^3*kg^-1*s^-2. Essentially, this means that the force of gravity (F) is determined by the product of mass one (m1) and mass two (m2), divided by the distance of the two objects’ centers squared (r^2), then multiplied by the gravitational constant (G). Consequently, N stands for Newtons which is the universal measurement of force, which is the product of the meter and kilograms divided by seconds.
However, the reason why stop signs on the streets do not fly into pedestrians walking their dogs (and vice versa) is that the gravitational constant, or the capital G, is an extremely miniscule force. A gravitational force, defined by the New Oxford American Dictionary, is “The constant in Newton’s law of gravitation relating gravity to the masses and separation of particles equal to 6.67e-11 N m^2 kg^-2” (insert link). In essence, this means that a gravitational force is the uniform measurement of gravity, and 6.67 x 10^-11 is an extremely small measurement (that is equal to 0.0000000000667 Newtons!).
So the force of gravity that is exerted from a pedestrian is 52.22 kilograms, and the stop sign is 3.75 kilograms, and they are a meter apart, the force of gravity between the two objects is equal to 1.3 x 10^-8 Newtons, or 0.000000013 Newtons. But the Earth is big enough where a person weighed 70 kilograms, they would be pulled at 668 Newtons. For couple hundred years, this was the accepted idea of gravity, until the Albert Einstein came along in the year 1905.
Einstein’s Theory
Contradictory to Newton’s ideas, Einstein had a completely new outlook on gravity. He theorized that gravity was not actually a force, but a curvature of the space-time dimension, also known as the fourth dimension. As objects attempt to move in the straightest line possible, they now move in a spherical direction, as the space-time dimension has been curved. He explained that the curvature of the space-time dimension can be visualized with a thin sheet of blanket. The blanket is stretched out as much as possible, with equal tension on all four corners of the blanket. This is the fourth dimension. When you take a marble ball (heavy mass like a star) and drop it in the center, everything starts to dip towards the center. Gravity, according to Einstein, also bends light, because of the curvature of the space-time dimension. Einstein was able to give a far more detailed explanation for gravity, and filled in many blanks and questions that had arose from Newton’s theory. Because of Einstein, we now have a fully different perspective on physics and
What is Gravity’s Effect on Matter?
Nevertheless, regardless of which scientist was correct, gravity’s effect is crucial to the existence of all matter in the universe. Although it is considered the weakest force out of the four forces or the four fundamental interactions (gravity, electromagnetism, the “weak” force, and the “strong” force; strength of each force in Newtons, respectively), gravity has nonetheless left its mark on the universe. It has the crucial(and at times devastating) role on humans and the Solar System/galaxy.
Effect on the Solar System and the Milky Way
Gravity keeps all the Solar planets orbiting, and keeps bodies of matter in space (most of the time) from colliding with each other. An orbit occurs because of gravity's effect on an object traveling in a straight direction. According to Newton's first law, all motion travel in a straight direction until an external force changes its direction. In this case, gravity is the external force that directs its path. As planets and asteroids attempt to move in a straight line, the gravity of the sun pulls the planets towards itself, resulting in an elliptical orbit.
Moreover, gravity also affects asteroids. Gravity is what causes asteroids to orbit the sun, and Jupiter’s gravitational pull actually keeps asteroids from bombarding the inner planets (Mercury, Venus, Earth, and Mars; closest distance from the Sun, respectively). The inner planets, though, also pulls on the asteroid belt, resulting in the inner planets and Jupiter both protecting each other from mass asteroid bombardment. Jupiter pulls on Ceres (the largest asteroid, responsible for one-third of the total mass of the asteroids belt) at a constant of 9e+20 N m^3*kg^-1*s^-2.
However, the reason why asteroid collisions occur is that asteroids have their own gravitational pull. At times asteroids may collide with each other, resulting in them knocking out of orbit, and may get into Earth’s gravitational pull. Usually, when an asteroid comes into Earth’s atmosphere it burns up in the mesosphere, but when the asteroid is big enough, it may create devastating effects on Earth. It is theorized that a giant asteroids collision on Earth was the cause of the extinction of dinosaurs.
Gravity is also the fundamental key to black holes. Although not very much is known about these astronomical phenomena, scientist believe that black holes existed since the creation of universe. NASA defines black hole as “A black hole is a place in space where gravity pulls so much that even light can not get out.”(Dunbar, Brian. “What Is a Black Hole?” NASA, NASA, 21 May 2015) A black hole’s a massive gravitational force comes from the fact that black holes contains incredibly massive amount of compact mass and density in such a small space.
Effect on Humans
Furthermore, gravity is also essential to the lives of humans.
Conclusion
Works Cited
Dunbar, Brian. “What Is a Black Hole?” NASA, NASA, 21 May 2015,
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