The weakest force of the universe

THE WEAKEST FORCE IN THE UNIVERSE

By: Risa Santoso 11 Diploma

Everything in the universe is made up of matters. Forces are what keeps everything from falling apart. Gravity, which are said to be the most dominant force in the universe are said to be the weakest force. To determine whether it is true or not, it is best to understand all of the fundamental forces first so to analyze them. There are a total of 4 fundamental forces of the universe; the gravitational force, the weak nuclear force, the electromagnetic-force and, the strong nuclear force.

As mentioned above, all the forces in the universe are based on the four fundamental forces. The strong and weak forces worked at very short distances. They are also responsible for holding certain nucleons and compound nuclei together. The electromagnetic force acts between electric charges and the gravitational force acts between masses. The last two forces have an infinite in range. The four fundamental forces have its own usages and calculations –they are very different in nature. To compare the strength of the fundamental forces, a dimensionless constant should be searched (to find the relative strength of each of the forces). This dimensionless constant is called the coupling constant.

First we can compare the coupling constant for the strong interaction in comparison to the electromagnetic force. It is clear that the strong force is much stronger simply from the fact that the nuclear size (strong force dominant) is about 10-15 m while the atom (electromagnetic force dominant) is about 10-10 m in size.

We first must know that a proton or neutron is composed of three quarks. These quarks have strong charges and are bound together by the strong force. There are, in total, of three strong force charges and three anti-charges. The particles which transmit the force are called gluons. Gluons are mass-less. These 8 kinds of gluons carry strong charge and a strong anti-charge. The strong force begins to act and gets stronger and stronger the further away that quark gets from the others. This is very different from the other forces which get weaker at longer distances. This occurs because the gluons have the color and anti-color charge. The strong force also acts between protons and neutrons in an atomic nucleus much in the same way that simple chemicals are held together by the electric force. The strong force binds the two protons with about 25-35 MeV of energy.

The body of data describing the strong force between nucleons is consistent with a strong force coupling constant of about 1:

Analysis of the coupling constant with quantum chromodynamics gives an expression for the diminishing coupling constant:

For the second force, the electromagnetic force causes electric and magnetic effects. It is long-ranged, but much weaker than the strong force. The force can be attractive or repulsive, and acts only between pieces of matter carrying electrical charge. In simple, the when the negative meets the positive charge, it will be attractive, and when the same kind of charges ...

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The body of data describing the strong force between nucleons is consistent with a strong force coupling constant of about 1:

Analysis of the coupling constant with quantum chromodynamics gives an expression for the diminishing coupling constant:

with the unit of energy times distance.

Another quantity relating to the electromagnetic force which occurs naturally in the interaction of radiation with matter is

A dimensionless constant that are gathered from the formula which characterizes the electromagnetic force is shown below.

This result appears naturally in the equations for many electromagnetic phenomena.

The weak interaction of the weak nuclear force has, like the strong interaction, such an incredibly short range that its strength must be evaluated in a different way than the electromagnetic force even though the weak force is just as strong as the electromagnetic force. Since the strong force and the weak force both have a similarity of being a short ranged force, it is best to compare their strength. As mentioned, the weak coupling constant can be related to the strong force coupling constant, which gives the result of:

Since the strong coupling constant has a value of about 1 in the energy range around 1 GeV, this suggests a value for the weak coupling constant in the range

After knowing the other three forces, we have to be able to relate them to the gravitational force. The gravitational force is present wherever matter is present. We are able to know from that the more matter that is present, the stronger the gravitational force is. This force can be said to be the dominant force in the universe because it is responsible for shaping the large scale structure of galaxies, stars, etc. From Sir Issac Newton’s theory of moon falling into the gravitational field and revolving around the earth because of the acceleration due to gravity (creating the orbit), he came to the conclusion that any two objects in the universe exert gravitational attraction on each other. This creates the relationship shown below.

with the unit of energy times distance.

Where m1 and m2 as the masses, , and r is the distance between the two point masses. This shows that the strength of can be related to the force between two selected masses.

Since the masses and charges of basic particles like the electron and proton are independent of each other, the strength of the gravity force relative to the electromagnetic force depends upon which particles you choose for comparison. If two protons are chosen for the comparison, then

Using the electromagnetic coupling constant of 1/137 then leads to a gravitational coupling constant, which calculation is shown below.

From the calculation and information above, a table regarding the strength of each of the fundamental forces can be formed.

Table of comparison between the strength (coupling constant) of each kind of fundamental forces

From the table of comparison above, a graph of comparison is made below.

We can see from the graph that there are much gap between the strong nuclear force and all of the other three. It is also clear that there are a gap between the electromagnetic force and both he weak nuclear force and the gravitation force. Since the gap of the relative strength of the weak nuclear force and the gravitational force is not that apparent, a graph of comparison is made below, still from the table of comparison above.

From this graph, it is clear that there are a huge gap between the strength of the weak nuclear force and the gravitational force. This also states that, from calculations, the gravitational force is much weaker than the other three, which makes the gravitational force the weakest force among the other four.

We can also know that gravity is gravitational force is weak by our everyday doings. Even though the gravitational force keeps us on earth, we are still able to pick things up from the gravity. While on the other hand, a magnet that we can easily get from the fridge and direct it to a pin, it can easily drag the metal pin and make it stick. This shows that the gravitational force, compare to the electromagnetic force is weaker.

From the study above, we are able to conclude that Gravity is the weakest force among the four fundamental forces acting on the universe. The gravitational force is indeed the only force that operates on a larger scale than the solar system but it works by the quantity of the mass acting on two objects. The gravitational force, even though are said to be the most influential force in the universe, it is the weakest force acting to our surroundings.

Proven to be the weakest natural force in the universe, in the recent research shown in BBC science, new possibilities concerning the gravitational force are still being researched. Since gravity derives everything, Lisa Randall from Harvard University explains that there might be a possibility that the gravitational force is actually as strong as the other three, or maybe more. She explains that there might be a possibility that the gravitational force are actually acting on a different dimension, a parallel universe, and that we are just experiencing a tail end of the real force. She tried to calculate how the force of gravity can leak from our membrane universe to the empty space but failed. This result opens up a possibility that the force of gravity might leak into our universe and not vice versa. This though has not been proven and still is a mystery yet to be solved and explained by evidence.

Bibliography:

Interview with Ms. Novi, High school teacher, majoring at science at Sekolah Ciputra Surabaya
Gravity: the weakest natural force on Earth? - Parallel Universe - BBC Science
Mellendorf K. “Gravity and the Event Horizon” Ask a scientist () [21 May 2009]
Fermilab; “How Strong is the Strong Force?” Inquiring minds () [22 May 2009]
Pathlights; “The Elemental Forces of the Universe” () [22 May 2009]
NASA; “NASA; Imagine the universe” () [22 May 2009]
Dr. Ken Mellendrof’s answer to “How gravity can escape the event horizon and affects the space surrounding the event horizon?”