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--------------------- 2651 - NATURAL CONSTANTS - are they changing?
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- The fundamental constants in nature include the speed of light, the gravitational constant, Avogadro’s number, the gas constant, Boltzmann’s constant, the charge on an electron, the mass of electrons, protons, neutrons, the permittivity and permeability of free space, Planck’s constant and several more.
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- Science keeps trying to measure these constants to higher and higher accuracies. But, they have no theory the will derive any one number. It is what it is.
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---------------------The speed of light in a vacuum = 299,792,458 meters / second
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--- The constant of gravity = 6.673 * 10^-11 meters cubed / kilogram * seconds squared.
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--------------------- The mass of the electron = 9.10938188 * 10^-31 kilograms.
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- It is difficult to remember these numbers because there is no pattern and, of course, they all change if you use different units of measurement. For example:
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--------------------- The speed of light in a vacuum = 186,282 miles / second
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- Scientists have tried to simplify things by expressing constants in terms of ratios that have no units. For example:
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--------------------------- The constant mass of a proton is 1.67*10^-27 kilograms.
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------------------------- The constant mass of an electron is 9.11* 10^-31 kilograms.
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-------------------------- The ratio of proton / electron mass = 1840
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- This ratio is unitless, it is a pure number, and easier to remember, the mass of a proton is 1,840 times the mass of an electron. And, it is constant.
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- In 1916, Arnold Sommerfeld introduced a constant applying the theory of relativity and quantum mechanics to the electromagnetic interactions of charged particles in empty space, and, inside the atom between the positive nucleus and the orbiting electrons. It is called the Fine Structure Constant.
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--------------------------- Fine Structure Constant = e^2 / 2*Eo*h*c
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- Fine Structure Constant = electron charge squared / 2 * permittivity of free space * Planck’s constant * the velocity of light.
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------------------------ It is a constant measured to be = 1 / 137.03599976
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--------------------------- Or, what most people remember as 1 / 137
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- See footnote (1) for the calculation and how the units all cancel out.
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- Astronomers have a way of measuring the Fine Structure Constant. When the light from a distant star passes through some interstellar gas the light radiation excites some of the gas atoms moving their electrons into a higher energy state. When this happens the atoms absorb a discrete amount of energy.
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- When astronomers look at a spectrum of this light they see dark absorption lines in the frequency spectrum where discrete energy bands are missing. Each element in the gas has its own unique spectrum of absorption lines because each element has its own atomic structure.
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- The elements iron, zinc, chromium, and nickel are especially affected by any changes in the Fine Structure Constant. The energy levels of electrons within the atom describe the light energy absorption process.
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- The energy of a photon is transferred to an electron, which jumps up the ladder of allowable energy levels. Each possible jump corresponds to a unique wavelength. The spacing of levels depends on how strongly the electron is attracted to the atomic nucleus. This electromagnetic force is a function of the Fine Structure Constant.
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- If we compare the light spectrum from the distant interstellar gas with the same gas elements in the laboratory we can detect any change in the Fine Structure Constant. Astronomers are looking at a distant gas that is backlit by a quasar.
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- A quasar is a quasi-stellar object that releases far more energy than ordinary stars and can be seen at great distances. It is believed that quasars are central black holes in distant galaxies. When their light reaches Earth it is redshifted due to the expansion of the Universe.
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- For example: the gas element absorption line in the laboratory is 543 nanometers wavelength. While the same gas element absorption line from the interstellar cloud is 544.5 nanometers. From this amount of frequency shift to longer wavelength (redshift) astronomers can calculate the interstellar cloud to be 7,500,000,000 lightyears away, also that far back in time.
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- In effect, astronomers are then able to compare the orbital structure of electrons 7,500,000,000 years ago to today. In 1999, their calculation showed a small, but statistically significant difference in the Fine Structure Constant. After measuring 128 quasar absorption lines they calculated an average increase in the Fine Structure Constant of 6 parts in 1,000,000 over the past 6 to 12 billion years.
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- Their measurement had to be very precise in order to distinguish this small difference. There was detailed uncertainty analysis needed of random and systematic errors that could creep into the measurements. By 2003, many astronomers have tried to duplicate these measurements. So far, they can not detect a change in the Constant in 1 part in 1,000,000.
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- The Fine Structure Constant in the electromagnetic force calculations is essentially the balance between the electric field energy and the magnetic field energy. During our Cosmic history we started with a radiation dominated era, to a matter dominated era, and now to a Dark Matter dominated era.
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- Possibly, these changes in our Universe caused the Fine Structure Constant to change, to increase very slowly over time. However, 2003 studies of the Cosmic Microwave Background Radiation has determined that the Constant did not vary more than 1 part I 100,000,000 (1 in 10^8).
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- So, results are still inclusive. Are our natural constants truly constant over time? Will some scientists ever figure out where these constants come from? What theory can be used to derive them? So much to learn, so little time.
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- (1) ------------------------ Fine Structure Constant = e^2/2*Eo*h*c
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------------------------------- The charge on an electron = 1.6 * 10^-19 coulombs
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------------------------------- Squared = 2.56 * 10^-38 coulombs^2
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----------- Permittivity of free space = 8.85 * 10^-12 coulombs^2 / Newton * meter^2
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------------------------------- Planck’s constant = 6.63 * 10^-34 Joules * seconds
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------------------------- Velocity of light = 2.99 * 10^8 meters / second.
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- Let’s try handling the numbers, the magnitudes, and the units separately:
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------------------------- 2.56 /2 * 8.85 * 6.63 * 2.99 = .00729
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------------------------- 10^-38 / 10^-12 * 10^-34 * 10^8 = 1
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------------ Coulombs^2 * Newton * m^2 * sec / coulombs^2 * Joule * second * m
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-------------------------- This reduces to: Newton * m^2 / Joule * m
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--------------------- A Newton is a unit of force = mass * acceleration = kg * m / sec^2
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----------------------- A Joule is a unit of energy = force * distance = kg * m*2 / sec^2
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------------------------- Kg * m * m * sec^2 / kg * m^2 * sec^2
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----------------------- The units all cancel out and we are left with a pure number:
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----------------------------------- 0.00729 , or
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---------------------------- The Fine Structure Constant = 1 / 137
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- March 5, 2020 619 2651
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--------------------- Friday, March 6, 2020 --------------------
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