Monday 13 July 2020

Liked on YouTube: The Four Fundamental Forces of nature - their origin & function


The Four Fundamental Forces of nature - their origin & function
• Signup for your FREE trial to The Great Courses Plus here: https://ift.tt/2CtjWbw. if you took a notebook, a plastic bottle, a toaster, and a glass container and burned them in a fire hot enough, around 10^31 degrees Celsius, all the particles and forces, would become one entity. This is what is believed to have existed at the moment of the big bang. All matter is composed of 6 quarks and 6 leptons and their 12 antiparticle pairs. But matter is subject to 4 fundamental forces that result in every action in the universe. These 4 forces are the strong force which binds the nuclei of atoms together, the weak force which is responsible for some kinds of radioactivity, electromagnetism responsible for the root cause of chemistry, and gravity which binds us to the earth. The best way to understand this and how these forces emerged is to visualize what happened at the big bang, when everything was one. Time began at the smallest time, Planck time, 10^-43 seconds. We are ignorant of anything that might have occurred prior to this 1st epoch of existence, called the Planck Epoch. All the forces and particles were in a point smaller than the size of a proton. Gravity separated from everything else, as it was the first force to separate out from the other 3 forces. The temperatures at this stage were 10^31 degrees Celsius, and the energies were in the range of 10^19 giga electron volts. The strings of string theory and the loops of loop quantum gravity, if those theories are correct, come into existence here. The next era, called the Grand Unified epoch lasts from the first Planck second up to about 10^-35 seconds. The Strong and weak force and electromagnetism were all unified. But shortly after this period, the strong force separated from the other two - electromagnetism and the weak force, which were united as one force called the electroweak force. Temperatures were now around 10^26 degrees Celsius. Cosmic inflation occurred. The universe which went from tinier than the size of a proton to the size of a grapefruit. At 10^-12 seconds, called the quark epoch, the electroweak force split into the weak force and electromagnetism. So at this point, all the 4 forces became distinct. The temperature of the universe cooled to 10^15 degrees Celcius, and energies are about 100 GeV. We know a lot about the universe up to this era because such energy levels can be modeled in particle accelerators. The Higgs field exists at this stage. That brings us to today, 13.8 billion years later, where the average temperature of the universe is -270 degrees C, and energy is 0.25 eV Gravity and electromagnetism are similar in that their mathematical formulas look nearly identical. Newtons law of universal gravitation is F= G Mm/r^2 . were G is Newton’s gravitational constant. Coulomb’s law of electric force between charged bodies is F = k Qq/r^2 where k is Coulomb’s constant. This means that the earth has a gravitational effect not just on the moon, but also some effect on every other massive object in the universe. This is a very small effect, but it is non zero. And since gravity effects all masses, this effect is the most influential force on a cosmic scale. But the electrostatic force between charges also extends infinitely far away. And this force is much greater than the force of gravity - 10^36 times greater. So why isn’t electromagnetism the most dominant force in the universe? ...because on large scales electric charges of most objects tend to cancel each other out. Large objects tend to be neutral. If large things were not electrically neutral, this force would completely dominate the universe. But Electromagnetism still has a big influence. It is the basis of all chemistry. So if electromagnetism is so strong, then what keeps multiple protons bound in the nucleus of atoms? They are kept glued together with a force one hundred times stronger, the strong nuclear force. However, it extends only as far as the width of a proton. This force is not simply the opposite of electromagnetism because it also holds electrically neutral atoms in the center of atoms. The release of this force is the energy behind nuclear bombs. The fission and fusion of atoms releases huge amounts of binding energy from the nucleus, which results from the strong force. It is also responsible for most of the mass of any object, not the Higgs Field. #fourfundamentalforces The weak force is responsible for beta radiation, which is the emission of electrons or positrons. One of the most important processes in nature is the beta decay of a neutron. If this decay did not occur, then the universe would have been full of neutrons, and no atoms would have ever formed. And we would not have life. But it’s effective length is only about one thousandth the diameter of a proton.
via YouTube https://www.youtube.com/watch?v=669QUJrF4u0

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