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The Four Forces 2012

Page history last edited by Mattson Rosenbaum 8 years, 6 months ago


The four forces are gravity, strong nuclear force, weak nuclear force, and electromagnetic force. These forces were separated at the time of the big bang, 14 billion years ago, when the temperature was around 1029 Kelvin. Since the temperature was so hot, the forces were created. All of the four forces use force carriers to govern the forces. Gravity uses the theoretical graviton, weak nuclear force uses the W and Z bosons, strong nuclear force uses the gluon, and the electromagnetic force uses the photon. The first force to be separated was gravity. The graviton has never been observed and scientists are trying to find it now. Gravity is the weakest force out of the four forces in nature, although it seems that it is the most prevalent in our lives. The relative strength of the four forces, are strong nuclear at 1, electromagnetic at 10-2, weak nuclear at 10-6, and gravitational at 10-38. Every particle can have electric charge, weak charge, color charge, and gravitational mass. 




Gravity became a separate force during the Grand Unification Epoch at 10^-43 to 10^-36. Its force carrier is the theoretical graviton, which must be massless and a spin two boson. Gravity affects all particles unlike the other forces which only affect particles like electrons or quarks. The gravitons bounce off an object and back to the more massive object. An attraction between the two are created. Gravity is generated from each and every fundamental particle that has inertial mass. Gravity seems to have no tangible effect on quarks or small particles, but it dominates large objects like planets. Gravity does not exist without the presence of a mass, therefore mass and gravity are completely linked to each other's existence. Every planetary body (including the Earth) is surrounded by its own gravitational field, which exerts an attractive force on all objects. Assuming a spherically symmetrical planet, the strength of this field at any given point is proportional to the planetary body's mass and inversely proportional to the square of the distance from the center of the body. This means that as an object gets two times farther away from a planet, the gravity on that object is 1/4 it used to be. A famous scientist named Isaac Newton created the laws of gravity. These laws were, every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them. Einstein created a better understanding of gravity in his theory of general relativity. His theory varies from newton's by a unified description of gravity as a geometric property of space and time, or space time. Although gravity is the weakest force, it has a large effect on the biggest objects in the universe.





Strong nuclear force-

The strong nuclear force is responsible for keeping quarks together and the fundamental building blocks for almost everything. It uses gluons as its force carrier. It is the strongest of the four forces, but particles must be extremely close before its effects are felt. The strong nuclear force was separated at 10^-32 seconds during the electroweak era. The strong nuclear force holds together neutrons and protons, which are a positive and a neutral charge. Protons attract to other protons in the nucleus of an atom, and neutrons attract to other neutrons. Normally positive and neutral don't attract like positive and negative, and positive and positive usually don't attract. The way that they do attract is by the exchange of subatomic particles called mesons. The meson bounces off each of the nucleons and keeps them attracted to each other. The pi meson theory has been replaced with the quantum chromodynamics, which says that gluons are the force carriers. It states that the force between gluons does not diminish as they are separated. Thus it is impossible to break apart a proton or a neutron. In very high energy reactions, gluons and quarks interact very weakly. The particles have to be as close as the diameter of a proton. The gluon keeps the quarks together, which makes up the nucleons. The quantum chromodynamic theory states that the strong nuclear force is the color force, where the colors are like the positive or neutral forces. There are six quarks in the standard model. The distinction between these six quarks is referred to as flavor, each of the flavors can have three color, red, green, and blue. The antiquarks are colored antigreen, antired, and antiblue. Mesons are quark-antiquark pairs, and baryons are one of each of the three quarks. The quarks are held together by the gluons, and the quarks and gluons hold the entire nucleus together. The strong force between two hadrons is considered to be a force between the quarks that make them up. 



Weak nuclear force-

The weak nuclear force is responsible for radioactive decay. The force carriers for the weak nuclear force are the W and Z bosons. Bosons have integer spin, like 1 or 2. If a nucleus separates, it will decay, and this is what the weak nuclear force is. The weak nuclear force is responsible for the sun. The strong and weak nuclear forces are linked because of this. It is most normally found in beta decay. Beta decay is when a nucleus decays with the emission of an electron or beta minus particle. Beta minus particles are indistinguishable from ordinary electrons, but the electron is created within the nucleus. A neutrino is involved in beta decay, and it carries off the energy, momentum, and angular momentum required to maintain the laws of conservation of matter. Beta plus decay emits a positron instead of an electron like beta minus decay. In beta decay, a neutron is turned into a proton. Apparently a d quark, which has a charge of -1/3 e, has turned into a u quark, which has a charge of +2/3 e. Charge conservation means that a negatively charged particle, namely W-, was emitted by the d quark. Since an electron and an antineutrino appear in the final state, they must have come from the decay of the virtual W- boson. The W and Z bosons have very large masses. Since they are so large, the range that they are effective at is small. This is the only instance where a quark can change to another quark. 




Electromagnetic force-

The electromagnetic force's force carriers are photons. It is the second most powerful force. We are very familiar with photons in our world, we use them to see. The electromagnetic force holds atoms and molecules together. 


Mattson Rosenbaum


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