The Strong Nuclear Force Increases with Distance

Super fact 129 : Most fundamental forces of nature, gravity, electromagnetism, the weak nuclear force, become weaker as the distance between the objects with the charges increase, except for the strong nuclear force, which grows stronger, not weaker, when the distance between the quarks increases. The strong nuclear force is strange in other ways too. Unlike the electric force which has two forms of charges, positive and negative, the strong nuclear force has three forms of charge denoted red, blue, and green. It has actually six kinds of charges if you count anti-red, anti-blue, and anti-green. I can add that the strong nuclear force is the strongest fundamental force in nature.

As you may know, atoms consist of particles. Electrons surround the nucleus of the atom. The nucleus of the atom is in the middle of the atom, and it consists of protons and neutrons. Electrons have a negative charge. Protons have a positive charge. Neutrons do not have an electrical charge. Electrons are so called elementary particles. They are not composed of other particles. Protons and Neutrons, on the other hand, are not elementary particles. They are composite particles consisting of quarks, gluons and quark pairs called mesons.

Quarks have electric charges, just like an electron and a positron, which is why a proton has an electric charge, a positive electric charge. However, as mentioned, in addition quarks have something called color charge. Unlike electric charges, which come in two forms, negative and positive, they come in three forms red, green and blue. In addition, there are also anti-red, anti-green, and anti-blue charges, making it six forms of charges. I should say that the color charges, red, green and blue, are not real colors. They are just names. Just like electric charges are associated with electric forces; color charges are associated with the nuclear strong force.

vector illustration of up and down quarks in proton and neutron on white background. The proton (left) is a red and blue up quark and a green down quark. The neutron is a red and green down quark and a blue up-quark. | The Strong Nuclear Force Increases with Distance
The proton and neutron each consist of three quarks. Protons consist of two up quarks and one down quark. Neutrons consist of two down quarks and one up quark. Both protons and neutrons have a net white charge. The yellow squiggly lines are gluons transporting color charge between the quarks. Asset id: 2333679305 by KRPD.

If you take an equal amount of positive and negative electric charges you get something that is electrically neutral. If you take an equal amount of red, green and blue you get what is called white, or neutral. If you take an equal amount of red and anti-red you also get white. Any other mix gives you a net color charge. As mentioned, unlike, for example, gravity or electromagnetism, which get weaker as objects move apart, the strong force grows stronger as quarks are pulled apart and weaker when they are squeezed together. This strange feature is referred to as Asymptotic Freedom.

As you separate a quark further and further from another the attractive strong force grows stronger and stronger until it becomes super strong, and at about 10,000 Newtons, which is more than one hundred billion times stronger than the force between an electron and a proton in a hydrogen atom it will finally quickly dimmish as if it was a rubber band that snapped. This event will create new particles and quarks, but not free quarks. 10,000 Newtons correspond to a weight of 2,200 pounds, like a small car. However, remember that we are talking about objects that are a trillion times smaller (in diameter) than one millimeter.

Not only is the nuclear strong force increasing with distance until it snaps, which is kind of strange, but by the time it snaps the force is shockingly gigantic for such a small particle. Therefore, this is a fact that is mind-blowing and kind of important to our understanding of the Universe and therefore I think it is a super-fact. With these kinds of forces inside the atomic nucleus no wonder we can blow up large cities using small amounts of the right matter.

The Other Fundamental Forces Become Weaker with Distance

As mentioned, the other fundamental forces gravity, electromagnetism, and the weak nuclear force get weaker as objects move apart. You may say what about friction, pressure, pulling a rope, and attraction between atoms in a molecule? Well, they are not fundamental forces and composed of electromagnetic forces at the bottom. Also, electric and magnetic forces are combined into electromagnetism because they are fundamentally the same thing.

Gravity gets Weaker as Masses Move Apart

The force of gravity gets weaker as masses such as planet Earth, the moon, and the sun are separated further. Newtons law of gravity states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

The picture shows the formula of Newtons law of gravity and an illustration of two objects being attracted to each other.
This diagram describes the mechanisms of Newton’s law of universal gravitation; A point mass m1 attracts another point mass m2 by a force F2 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 (r) between the point masses. Dennis Nilsson, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons
Gravity force field lines spreading out around Earth. | The Strong Nuclear Force Increases with Distance
The force field lines demonstrate how gravity gets weaker as the gravitational field spreads out in space. I generated this picture using ChatGPT.
The picture depicts an Earth bending spacetime around it.
Even if you use the more modern model of gravity, Einstein’s General Theory of Relativity, you can see how the curvature of space becomes less further away from Earth. I generated this picture using ChatGPT.

This does not happen with the strong nuclear force.

The Electromagnetic Force gets Weaker as Objects Move Apart

The electric force gets weaker as the charges are separated further. Coulombs law is similar to Newtons law of gravity. The force between them is inversely proportional to the square of the distance between their centers.

The picture shows the formula of Coulombs law which has the same form as Newton’s law of gravity plus an illustration of a positive and negative charge being attracted to each other and two positively charged particles repulsing each other.
The magnitude of the electrostatic force F between two point charges q1 and q2 is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them. Like charges repel each other, and unlike charges attract each other. File:CoulombsLaw.svg: User:Dna-Dennis / *derivative work RJB1, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.
Electric force field lines spread out around a positively and negatively charged particle.
The force field lines demonstrate how the electric force gets weaker as the electric field spreads out in space. I generated this picture using ChatGPT.
The picture shows magnetic force field lines spreading out around a magnetic dipole. They are spreading farther apart further away. | The Strong Nuclear Force Increases with Distance
Same thing with a magnetic dipole. The field lines are spreading out in space so the magnetic force (field) become weaker further away from the dipole. I generated this picture using ChatGPT.

Again, this does not happen with the strong nuclear force. It is different. The strong nuclear force is strange and very strong.

What is a Quark?

You can learn more about Quarks and the strong force by watching this 10 minute video below. The strong nuclear force is discussed towards the end of the video.

Other Physics Related Superfacts

To see the other Super Facts click here

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Author: thomasstigwikman

My name is Thomas Wikman. I am a software/robotics engineer with a background in physics. I am currently retired. I took early retirement. I am a dog lover, and especially a Leonberger lover, a home brewer, craft beer enthusiast, I’m learning French, and I am an avid reader. I live in Dallas, Texas, but I am originally from Sweden. I am married to Claudia, and we have three children. I have two blogs. The first feature the crazy adventures of our Leonberger Le Bronco von der Löwenhöhle as well as information on Leonbergers. The second blog, superfactful, feature information and facts I think are very interesting. With this blog I would like to create a list of facts that are accepted as true among the experts of the field and yet disputed amongst the public or highly surprising. These facts are special and in lieu of a better word I call them super-facts.

45 thoughts on “The Strong Nuclear Force Increases with Distance”

  1. I learned something new from this, and I love how clearly it explains such a mind-bending concept. I’d never really grasped that the strong nuclear force actually increase with distance until it effectively “snaps”… The comparison of 10,000 newtons to the weight of a small car really puts the sheer scale of these forces into perspective. Fascinatingly explained!

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    1. Thank you so much Patricia. I agree the size of the force for something that is 10 million times smaller than an atom is just astounding. The nuclear force really become gigantic before “snapping”. In the past I remember reading books where they claimed that it became infinite with increased distance before they knew it would actually “snap” and create one or more new particles.

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  3. This takes us way beyond grade nine science class. I doubt if many people understand these concepts you’ve just told us about, but it amazes me that some have managed to understand them and even make them work for (or against) mankind.

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        1. Yes it is on both accounts. I guess one to think about the force between quarks as a super strong rubber band that pulls back harder and harder though more you pull until it finally snaps when the force is unimaginably large.

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  6. Thank you for the fascinating discussion of the strong force. This was not something we covered much during my astrophysics studies, so it’s very interesting information. For us, gravitation and electromagnetism were the dominant forces we studied.

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    1. Thank you so much David. I knew about some of this because of the nuclear physics class I took back in college for my physics degree. This is hardly common knowledge. However, as you know I am trying to dig out the mind blowing or surprising stuff. Gravity and electromagnetism is certainly very fascinating and can get extremely complex.

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  10. Hi Thomas, this certainly helps demystify why nuclear forces are so powerful. You’ve done a nice job of explaining this concept. You are a much better teacher than my science teacher was. He also didn’t like girls and had a tendency to ignore the four of us who took his class.

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        1. I guess that is very old fashioned. When I was young in Sweden all science and physics teachers I came across welcomed girls very much. On the contrary the class rooms tended to have more boys so more girls to make it more even was welcomed.

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    1. Thank you so much for your very kind words Debbie. I really appreciate your support. This post was certainly abstract but maybe the details aren’t so important. But knowing how strange and extreme nature’s strongest force is, is kind of mind-blowing.

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    1. Thank you so much Mihran. Yes that rubberband like behavior of increasing force with distance instead of weakening is very strange for fundamental force between particles/objects not attached to each other, but it is real and super strong. I really appreciate your kind comment.

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