Atomic Forces and the Existence of Matter

Atomic Forces and the Existence of Matter

This article is dedicated to my dear nephew, Dr. Lim Mingyann, who is a Consultant ENT Surgeon at Tan Tock Seng Hospital in Singapore who asked me an intelligent question through Whatapp. I live in Malaysia, and he in Singapore. Here is what he wrote:

“Uncle Ju Boo, Mingyann here. Can I ask your opinion, is it true that if the strong nuclear force is stronger than it is, hydrogen would not form. If it was weaker than it is, no elements other than hydrogen could exist. Do u agree with these two statements?  If you do, could u please explain why? “

Thank you.

Mingyaan

Thank you for your question my dear Mingyaan. 


It is really a superb question. I have never thought of this before. You are a very intelligent and a highly qualified medical specialist and surgeon like your father,  and have used this to confront and challenge  me with an extremely difficult and thought-provoking question. 

Honestly I have  never thought of this myself in my entire life. Where did you get this question from? 


How come from medicine you have gone into nuclear physics which is a very tough field meant only for scientists like Albert Einstein, Julius Robert Oppenheimer, Enrico Fermi and Ernert Rutherford and a few other scientific genesis 

J. Robert Oppenheimer
J. Robert Oppenheimer, c. 1944
Born	April 22, 1904 New York City, New York
Died	February 18, 1967 (aged 62) Princeton, New Jersey
Nationality	American
Alma mater	Harvard College Christ's College, Cambridge University of Göttingen
Known for	Nuclear weapons development Tolman–Oppenheimer–Volkoff limit Oppenheimer–Phillips process Born–Oppenheimer approximation
Spouse(s)	Katherine "Kitty" Puening (1940–1967; his death; 2 children)
Awards	Enrico Fermi Award (1963)
Scientific career
Fields	Theoretical physics
Institutions	University of California, Berkeley California Institute of Technology Los Alamos Laboratory Institute for Advanced Study
Thesis	Zur Quantentheorie kontinuierlicher Spektren[1] (1927)
Doctoral advisor	Max Born
Doctoral students	Samuel W. Alderson David Bohm Robert Christy Sidney Dancoff Stan Frankel Willis Eugene Lamb Harold Lewis Philip Morrison Arnold Nordsieck Melba Phillips Hartland Snyder George Volkoff
Signature
Notes
Brother of physicist Frank Oppenheimer

Your question really sets me thinking for a while, and wondered how to answer this question.  


I found the answer is not simple as it involves a combination of our understanding on physical chemistry, nuclear physics, and astrophysics separately to be combined like a neutron star or a black hole which I shall explain later, and I am definitely not an expert in these area of nuclear sciences. 

   

But I shall try to field your challenge 

But first of all, let us understand what an atom is.

Structure of an Atom:

An atom is the smallest particle of matter that can take part in a chemical reaction involving the exchanges and transfers of its outer electrons with other atoms or molecules.

It consists of a central nucleus with electrons spinning around it held together by an electromagnetic or electric force.

The nucleus of an atom consists of protons which are positively charged, and neutrons that have no charge.  The electrons orbiting around the central nuclei are negatively charged. Their charges are opposite to each other so that there is an attraction between protons and electrons. 

The forces of attraction between the proton and electron and the outwards centrifugal force of an orbiting electron keeps the electrons from touching the protons. This keeps the atom stable as the two forces equate each other.

The nucleus of an atom consist not just a proton, but may also have many protons with equal numbers of electrons to balance the charge. They may also have many neutrons that have no charge. Together, the proton and the neutron in the nucleus, it is called a nucleon.

The simplest atom is the hydrogen atom which has only one proton and a single electron orbiting around it. It has no neutron in it except for its much rarer isotopes.

Hydrogen is also the simplest and the most abundant element in the entire Universe from which the Sun, the stars and the galaxies are derive their energy.

Forces in an Atom and Gravity:

There are two forces in an atom. One is an electric force, also called electromagnetic or Coulomb force that holds the proton and electrons together, the other is a very strong nuclear force that binds the proton to the neutron together in the nucleus.

The electromagnet tic force that ties the proton and electron together has a strength that lies between the nuclear force which is the strongest force known, and the weakest one which is the force of gravity. A nuclear force is some 137 times stronger than an electromagnetic force.

Even by itself, an electron pack some energy by spinning. Electron spin is a kind of angular momentum which is part of the quantum property of electrons. The magnitude of this angular momentum is perpetual.  If the electron spins clockwise on its axis, it is defined as spin-up but if it spins counterclockwise it is designated as spin-down.

The electromagnetic force not only binds electrons to the nucleus, but also binds the atoms together to form molecules. The molecules themselves form the various  chemical compounds by these intermolecular forces, while the powerful nuclear force holds the nucleus together. 


Of all the forces in Nature, strongest is the nuclear force. 

Nuclear force although is the most powerful force inside the nucleons, they can only act over very short distances of about 1 femtometre (fm, or 1.0 × 10⁻¹⁵ metres). Beyond 2.5 fm, it rapidly decreases into insignificance. 

For instance, the dimension of an atom is about 1.0 × 10⁻¹⁰ m. This is 100,000 times further away  than the distance a nuclear force can reach or  act over  an electron that is orbiting around its nucleus.

At distances less than 0.7 fm, the nuclear force is strongly repulsive. This repulsive distance dictates the physical size of nuclei, since the nucleons can come no closer than the force permits.

The force of gravity on the other hand, albeit the weakest among all the forces in an atom, it can act over very long distances.  

Its effect is felt even between the stars as seen in binary or triplet stars systems as they revolve around each other. Their revolution is held by this long-distance force.

We can also see how gravitational force holds all the eight planets of the Solar System together as they take their circuit around our own Sun. Its presence is also felt beyond Pluto at a distance of 5.872 billion kilometers and even beyond Pluto such as the Oort Cloud at lazes at the fringe of the Solar System. 


The Oort Cloud harbors a huge collection of comets lying between 0.03 to 3.2 light years (2.84 x 10¹¹ - 3.03 x 10¹³ kilometers) away.

It is a target of a tug-of-war between the gravitational pull of the Sun and that of passing stars or even the Milky Way itself. The gravitation effects on the Oort Cloud is so effective even over such long distances that it can occasional dislodge comets from there and send them hurtling towards the pull of the Sun 

Gravitation force although the weakest of all, is perpetually present as long as matter continues to be present.  Its force permeates throughout the entire Universe. Their strength is the product of the masses of two or more bodies, and falls off inversely as the square of their distances.

Hence  gravitation force is always present theoretically no matter how far the bodies of attraction are apart even though astronauts often speak of zero gravity when they are orbiting the Earth when in practice there is no absolute zero gravity there. Eventually their space crafts will be pulled back by gravity to Earth.

Gravitational force is just 6 × 10^-39 times the strength of a nuclear force just to compare. So it is really very, very weak, but it can act over very long distance whereas nuclear force cannot 

 So we can clearly see there is a lot of forces and energy in Nature whether in an electron spin, in the inter proton-electron space, in the nuclear of an atom or among the stars and galaxies where the persistent gravitational forces holds them together. 


You cannot remove, destroy or unbind gravitational forces. They are always there in all perpetuity.

Even in the Bible this force among the stars is clearly mentioned.  “can you bind the chains of the Pleiades or loose the cords of Orion?” (Job 38:31).

Understanding the nature of these forces is crucial as they are the key to the answer your question. We shall explain as we go along.

Sub-atomic Particles:

Within the nucleus there are also sub-atomic particles. For instance, protons are made up of even smaller particles called quarks, and both are held together by gluons which are exchange particles between the strong interaction of protons and neutrons.

Neutrons again are also broken into quarks. Each neutron is made of three quarks, two down quarks and one up quark. A powerful nuclear force also binds the quarks together.

This strong bondage among all the sub atomic particles in the nucleus is the nuclear force. Splitting the proton and neutron apart, releases this strong force, called nuclear energy

The Hydrogen Atom:

However, a single neutral hydrogen atom has no charge except when it is charged by some external energy such as by light, ultraviolet radiation or electricity. When energized, it   then becomes excited, and ionizes. 


By itself, it is electrically stable as it contains only a single positively charged proton and a negatively charged electron held to its nucleus by the Coulomb force. 

In some rarer forms of hydrogen there is also a neutron in their nuclei. These are the isotopes of hydrogen. In these isotopes, a nuclear force is present.  


In other elements where there are protons and neutrons, the same nuclear force is also present. A nuclear force binds all the nuclear particles together while the electromagnetic force holds their orbiting electrons.

It is not possible to spilt a normal hydrogen atom because it has only one proton with no neutron in its nucleus.  Hence there is no nuclear force there. The only force in the hydrogen atom is the weak Coulomb or electromagnetic force that binds its proton to its single electron as already explained.

However the energy levels of the electromagnetic force of a hydrogen atom can vary. This depends on how far the electron is away from its proton. This distance is called the Lorentz radius.

The electron distance to the proton is the shortest  when it  is at ground state, but it may jump orbit to 1st, 2nd and the 3rd levels or stages written as n1, n2, n3 and n4 when its atom is excited by an external energy.

The way the electrons orbit its nuclear is very much like the planets around the Sun except in the former it is controlled by electromagnetic forces, whereas the latter by gravitational force.

In nuclear physics for atoms, this is labeled as the Rutherford–Bohr model or Bohr model put forward by Niels Bohr and Ernest Rutherford in 1913.

Minimum Energy:

It requires a minimum amount of energy designated as “ionization energy” to peel off the electron from the hydrogen atom for it to ionize. The energy stored by a hydrogen atom occurs at various levels pending on the levels of the orbit of its electron bound to the nucleus.

However, it cannot have just any value of energy because the electron can only occupy certain orbital “states”, and at in each state they store in only a specific amount of energy.

The lowest energy level an electron can have is at “ground state”. When it jumps orbit and reaches a higher energy than this lowest energy, it is said to be in an “excited state”.

Electrons with high n numbers are so weakly bound that even feeble disturbances will wrench the electron away from its nuclear.

In both classical physics and quantum mechanics the absolute value of energy is immaterial; only their energy difference is important. When ionized, the electron will have zero binding energy to the proton. Based on this concept,  the different energy levels of a hydrogen atom are given by the equation:

E = - E0 / n2,

where E0 = 13.6 eV (1 eV = 1.602×10-19 Joules) and n = 1,2,3… etc, so that the ground state has energy E1= -13.6 eV and the second energy level (the first excited state) has energy E2 = -13.6/4 eV = -3.4 eV… etc.

When excited, it may lose its sole electron by escaping its outer orbit. It is becomes ionized. However, the electron seldom can escape completely as it is strongly held by the proton unless it is at the highest n level.  If this happens, the electron will escape leaving the proton behind.

However this seldom happens in Nature because a single hydrogen atom unattached to another hydrogen atom or with other atoms or molecules especially with carbon atoms seldom exists in the environment of Earth as it is very reactive. It has to coexist with other atoms and molecules and the tens of millions of compounds especially in organic compounds alongside with carbon.

But should it escape, it tends to look for another hydrogen atom to form a hydrogen molecule rather than existing as a single atom. A hydrogen atom that has a single electron is unpaired and is highly reactive, and very unstable.

By itself it may be considered as a free radical as it has no partner with another electron. As such being very reactive it will seek another hydrogen atom to stabilize itself where the second  hydrogen  atom with another electron can contribute to its stability by providing a covalent bond for it to become a more stable hydrogen molecule (H2).

   

Any molecule that has an unpaired electron is a free radical, or redefined as any molecular fragment that contains an unpaired electron in an atomic orbital.

A single atom with an unpaired electron may be considered to fall into this category. Hence two hydrogen atoms will seek each other to form a link as a hydrogen molecule which is much more common and more stable in the vicinity of Earth.

Once any fragment of an atom or molecule becomes a free radical it will be extremely unstable as it has an unpaired valence electron. 

In such an event, the molecule will try to snatch a nearby electron from another molecule somewhere to stabilize itself, and the neighboring molecule which has lost its electron to the free radical will in turn snatch another electron from another neighboring molecule causing a chain reaction. These chain reactions can occur at lightning speeds as free radicals are very unstable. 

So we can see in Nature there are a lot of energy and forces required in all types of reactions, and all requires a minimum amount of energy for chemical reactions to occur. 


Often in a chemical reaction they give off excessive energy in form of heat as in combustion. But they can also absorb energy for them to react. One is exothermal, the other endothermal reactions.

The energy levels in an atom are electromagnetic in nature and the role their electrons play in chemical reactions are normally their exchanges   with other molecules.  Nuclear forces are not involved in chemical reactions.

In short, if there is no nuclear force in an ordinary hydrogen atom, then the existence of hydrogen mentioned in the question does not arise. We shall explain that later.     

Isotopes of Hydrogen:

However, if we are referring to hydrogen in its atomic stage then we are referring to the most common form called “protium” which has only one proton and one electron.  But there is also another common form of hydrogen atom, called “deuterium” which has one neutron besides its proton and an electron.  

This is an isotope of the normal hydrogen atom.  Two atoms of deuterium, called heavy hydrogen is formed when they combine with one atom of oxygen to produce heavy water. 


The oxygen is the same as in both regular water and heavy water. Heavy water is about 10% heavier than ordinary water, but chemically, heavy water and ordinary water are the same.

Besides deuterium, there is also another isotope of hydrogen called tritium with two neutrons. The isotope tritium is unstable and is radioactive. Tritium among the three common sotopes of hydrogen is less stable. It is radioactive decaying into helium. 

Its water is considered a waste product in nuclear reactions, and it becomes a health hazard if it leaks into the ordinary public water supply.

Other isotopes of hydrogen are much rarer, and are all radioactive and highly unstable and we shall not go into them.

The most common form of hydrogen (protium) makes up 99.98 % of all the hydrogen, followed by deuterium which is 0.016 % and tritium at less than 0.01 %

Thus only the isotopes of hydrogen have nuclear force in them, but not the ordinary hydrogen (protium).

Even if you spilt an isotope of hydrogen, the energy released would be much less than say uranium which packs so much more energy in its nucleus as it has so much more protons and neutrons in it which can be released by a nuclear chain reaction. 

Uranium – 235 for instance, has 92 protons and 143 neutrons in its nucleus, and when an atom of uranium 235 is split, it releases much more nuclear energy through this chain reaction by splitting all the proton-neutron it packs one after another.

  

However, you could also get nuclear energy from hydrogen by fusion from the isotopes of deuterium and tritium as in a hydrogen bomb

Fusion Energy of Hydrogen:

Alternatively, you can also fuse hydrogen atoms together like in the Sun and stars into helium to yield an enormous amount of energy. This energy is called fusion energy or energy of nuclear fusion.  

What happens in this fusion cycle is that the proton of the hydrogen nuclei, together with electrons neutrinos and photons, fuse together generating a helium nucleus with the release of fusion energy.

This is the only form of nuclear energy we can extract from hydrogen as seen in the Sun and stars.  But in an ordinary hydrogen as we know it, the hydrogen stay inert and neutral unless burnt to release the heat of ordinary chemical combustion.  


Chemical or electrical energy can also be used to excite and ionize a hydrogen atom. But you cannot get nuclear energy out of ordinary hydrogen. So again this question you asked does not apply.

Other Possibilities:

However if the question is on any possibility on the existence or non-existing of ordinary hydrogen or other elements pertaining to nuclear forces if weaker or greater than the forces of attraction between the electron and its proton, this may still be a valid question but only seen  in one scenario.

In order to answer that, we need to go beyond physical chemistry or nuclear physics.  We need to bring in the stars and astrophysics as well  to help. We shall discuss this shortly. 

Other Elements & Sub-Atomic Particles:

The nucleus of other elements consists of positively-charged protons and the same numbers of negatively-charged electrons.  But they may also have different numbers of neutrons without charge.

Hence they can have isotopes too containing a certain number of protons, but different numbers of neutrons.  In such cases, they will differ in relative atomic mass, but not in chemical properties. With the presence of their isotopes, they become the radioactive form of the element.

In the early stages of the universe the key reaction was the collision of protons and neutrons to form deuterium nuclei  which is an isotope of hydrogen as already explained.

Since hydrogen is the most abundant element in the Universe, we need to rephrase the question to refer it as electromagnetic force in a hydrogen atom rather than nuclear forces unless we are talking about higher elements like uranium 238 which has an atomic mass of 238, consisting of 92 protons and 146 neutrons.

This multiple numbers of particles in uranium, especially uranium 235 makes uranium packed with nuclear energy, much more than the combined electromagnetic forces.

  

However we still have only one exception for hydrogen. Since hydrogen is not fissile, it can be fused together to release fusion energy as occurring in the Sun and stars that converts hydrogen into helium as already explained earlier. 

The Sun for instance generates about 3.86 x 10²⁶ watts of energy by converting hydrogen into helium.

The Sun converts 600 million tons of hydrogen into 596 million tons of helium every second. But only a mere 4 million tons of hydrogen are converted into energy.

Most of that energy is dissipated into space, and only about 1.74 x 10¹⁷ watts arrives to Earth. This is about 174,000,000,000,000,000 or 174 quadrillion watts after a 150 million km journey to reach this Planet.  

Hydrogen constitutes about 75% of the baryonic mass of the universe, and hence there is a lot of energy in the Sun, stars and galaxies too.  

Baryonic matter includes matter composed of baryons, protons, neutrons and all the objects composed of them in the atomic nuclei, but exclude things such as electrons and neutrinos which are actually leptons.

A baryon is a member of one of two classes of hadrons which are particles built from quarks and thus experiencing the strong nuclear force. Baryons are heavy subatomic particles that are made up of three quarks.

Both the protons and neutrons, as well as other particles, are called baryons. The other class of hadronic particle is made from a quark and an antiquark is called a meson. But we shall not dwell too much into nuclear and particle physics.

The Sun and Neutron Star:

Having explained all the above, we are now ready to answer your question whether or not hydrogen can exist if its nuclear force, or rather the electromagnetic force between its proton and electron is less than it is.

But before that, let us look at the Sun once again. As already briefly explained, the Sun generates its own energy by converting its hydrogen into helium through nuclear fusion.

  

The Sun is predominated hydrogen. Based on mass, the Sun is composed of 75 percent hydrogen and 25 percent helium. Other elements make up less than 0.1 percent of the mass of the sun.

Even though the Sun is approximately 130,000,000 the volume of Earth  based on its radius which is 109 times that of Earth, its density is lighter at about 1.4 g/cm3 compared to that of Earth at 5.5 g / cm3.

This is because it is mainly made up of light elements like hydrogen and helium.  The Sun composition is similar to the Gas Giant planets compared to Earth which is made of heavier elements and their compounds that are formed through what is called “nucleosynthesis”  from hydrogen during the early stages of the Universe formation.

The Sun was formed about 4.6 billion years ago. The Sun will continue to ‘burn’ its nuclear fuel silently for another 4.5 – 5.5 billion years until the hydrogen in the sun's outer core is depleted.

Currently the searing heat of its nuclear fusion causes the Sun to maintain its volume and size. The intense heat keeps the particles apart and prevents them from collapsing. But once its hydrogen fuel is used up, it begins to cool. Once it begins to cool, its own gravity will cause it to collapse.

The crushing pressure will trigger off another cycle of fusion. It will continue to generate heat for another 2 billion years where it will fuse the helium into carbon, some oxygen and other elements, but with lesser amounts of energy. 


This is achieved through a series of reactions called nucleosynthesis as already mentioned.

After all its hydrogen fuel is spent, it will either contract into a white dwarf, or expand into a red giant to engulf the Earth and all the other planets possibly  up to Pluto and even beyond  in the Solar System

Massive Stars:

However, there are stars that are much more massive and denser our Sun. These are also giant stars.

If the hydrogen fuel in massive stars between 10 to 29 solar masses runs out, it will explode as a supernova. Even after its outer layers are blown off, it will still have enough remaining mass and pressure to fuse its hydrogen, carbon and other elements together.

Neutron Stars and Black Holes:

However, when a very massive star blows out its outer coat as a supernova, its interior core may still have sufficient mass to collapse onto itself.  If it happens it may either turn into a neutron star or a black hole depending on its remaining mass or the original mass of the star.

Another possibility is, if a star is massive enough it may not even blow up as a supernova, but collapse directly to form a black hole leaving no core behind. All these cosmic events are hypothetical scenarios in astrophysics.

But what happens if a star is massive, but not massive enough to become a black hole at the end of its life?

The Weakest is Now the Strongest: 

Here’s what may happens as I promised to write earlier about the existence of a neutron star. Its own gravity will cause it to contract to such an extent until the electromagnetic force that keeps the proton and the electron apart in its remaining hydrogen,  can no longer withstand the inward force of such a massive gravity. 

The weakest force in Nature has now become the strongest and the most prevailing.

Inside a neutron star, the scenario of gravitation is different.  The gravity would be so horrendous that it will force the negatively- charged electrons to merge with the positively-charged proton which under normal Earth’s gravity are kept separate by orbiting even though they have opposite charges.  


When that happens, a neutron with no charge will be formed. The negative and positive charges will cancel out each other to form a neutral neutron.

In such a scenario when an electron gets sucked in into the proton, we call it as an Inverse Beta Decay or an Electron Capture.

Once all the remaining hydrogen atoms and other atoms of other elements are fused into neutrons, nothing remains except neutrons. The star then becomes a neutron star. 


In short, the force of gravity has finally taken over by accretion and have brought all the particles together and neutralize them into neutrons. 

There will be no more hydrogen. There will also be no other elements left. Every bit of particles and sub-particles will be reduced to neutrons which stays neutral. 

There is no energy left except the eternal force of gravity. Neutron stars are dead stars that emit no light or energy.  

Neutron stars are the smallest and densest of all stars other than the so-called theoretical quark stars. They have a radius of about 10 kilometres with a mass between 1.4 and 2.16 solar masses. 


They are usually the result of a supernova explosion of a massive star that compresses its core past the density of white dwarf to that of the atomic nuclei.

Existence of Matter in a Weaker Force:

But in your question, what happens if the “nuclear” force is weaker than it is, will hydrogen be formed?  

As already explained the weakest force within an atom is the electrical or electromagnetic force, also called Coulomb force which is the force between two charged bodies or particles. 


If this force is even less than what binds the proton and the electron together as in a hydrogen atom, then the proton can no longer hold the electron anymore. The electron will escape, and only the proton is left. 


A proton without an electron attached is not considered a hydrogen atom. It is just an incomplete part of matter and hardly exists  in isolation as we know it.

As to the question if the “nuclear” force was weaker than it is, no elements other than hydrogen could exist.

In such an event, even a hydrogen atom which must have at least an electron If it does not then it cannot exist

If the electrical force is less than what it is, then there is a likelihood the electron will fly away leaving behind just the proton. A single proton per sec cannot be considered a hydrogen atom as already explained. 


It must have at least one electron orbiting or two in the covalent bond of a hydrogen molecule.

As for the other elements there is also the same  hypothetically possibility that they too cannot exist because in all other elements more massive than hydrogen containing more than just one proton and one electron they must collectively have a  net electrical force to bind all the particles together.

Such a combined force of multiple protons and electrons will be much greater than the single force than binds the particles of a single hydrogen atom.

If these forces are less or absent, then no other element or even hydrogen can exist as there will be insufficient force to tie so many electrons and equal numbers of protons together. 


All elements including a hydrogen atom must have at least a minimum electrical force even at ground state as discussed earlier.

It is this combination of forces that bind the protons, neutron and electrons together that makes other elements more massive than hydrogen to exist in Nature. 

The electrons without sufficient binding force will all fly away either by attraction to other unpaired atoms or molecules, or by their sheer outwards centrifugal forces which is normally balanced by the inward pull of the electrical force during their orbit around its nucleus.

Without these forces, whether weaker or stronger than what it is, no substance or matter, whether hydrogen, other elements and all the different types and millions of molecules and chemical compounds can exist.

Before all of them can exist there must be a minimum amount of force to bind them together, and the minimum of them other than gravity is found in the simplest and the most abundant of all elements in the Universe which is the hydrogen atom in its unexcited or ground state. 


Anything less than this, no atom can exist – not even a hydrogen atom.

Yes, in that sense your question is valid.

I hope I have explained adequately, and have been of help? I hope you enjoy reading it. 

Thank you once again for your very challenging and very difficult question you confronted me with your very high intelligence which sets me wondering and thinking myself for a while before I could pen this article which I have now dedicated it to you my dear nephew Mingyaan.

Uncle lim ju boo