All human beings have similar organs, but each organ has qualities unique to itself and to the person it belongs to. Research has revealed that even some of the genes of monozygotic twins are different [1]. As opposed to the previous assumption that “when it comes to DNA, every cell in the body is essentially identical to every other cell,” it has been found that each cell has a DNA of its own [2]. This uniqueness originates from the fact that the order and number of molecules and proteins are different, which is valid for atoms and sub-atom particles as well. Having spent countless hours on microscopes and spectroscopes, a university professor of mine once said, “I witnessed different structures of iron atom each time I observed one. We even need to produce a separate periodic table for the iron element alone.”

We also witness that particles have been created uniquely, just like human beings are. From the micro universe (one millionth of a meter) down to femto universe (one quadrillionth of a meter), each particle is called a boson or fermion. When particles are examined to find out in what conditions they resemble each other in the femto universe, doors of a new world will be opened in terms of knowledge and contemplation. According to this new perspective, while the things and events are sometimes explained through mathematical equations and formulations, they are sometimes explained through experiments of thought trying to attain the truth behind them. Pauli exclusion principle is one such experiment.

Pauli Principle

There are around 380 sub-atomic particles [3]. In atomic and subatomic dimensions, two fermions (e.g. two electrons) of an atom cannot have the same set of quantum numbers. Wolfgang Pauli first explained this principle in 1925 and was awarded the Nobel Prize in Physics in 1945 after experiments proved that the theory was correct. This theory has gone down in history as the Pauli Exclusion Principle.

The motion equations of subatomic particles are expressed by their magnetic states. Pauli said that none of the electrons of an atom can share the same quantum state at the same time. In other words, two electrons in the same atom cannot share the physical features such as magnetism, motion, position and velocity in the same state [2].

In addition to the three quantum numbers (principal, subordinate, and magnetic quantum numbers) described so far, Pauli defined a quantum number for the spin of a fermion (e.g. electron). The spin quantum number is related to the rotation of the electron around its axis because an electron rotates around its own axis as it rotates around the atomic nucleus. According to the Pauli Principle, if an orbit has an electron with a spin of 1/2, an electron with a spin of -1/2 can be placed in the same orbit. If we assume that the spin of an electron rotating clockwise is 1/2 the spin of an electron rotating counterclockwise will be -1/2. Thus, with Pauli’s contribution, four quantum numbers were defined for subatomic particles and it was stated that even if the other three quantum numbers were the same, electrons with different spin quantum numbers could circulate in the same orbit.

The Pauli Principle shows that atoms are not identical. This principle also applies to solid crystals, that is, the materials we use daily. The Principle is also able to explain the fact that the ores that make up the element are different, and the fact that there are different elements in the periodic table. With this principle, important properties of superconductors have been discovered.

In 1927, based on the Pauli Principle, German physicist Karl Werner Heisenberg showed that it is not possible to measure the physical properties of a particle, such as the position and momentum, at the same time and that these results can only be expressed with uncertain probability and statistics [5].

This uniqueness also manifests itself in the space we call the macro world. Stars consisting of only neutrons are called neutron stars. A neutron star is very dense: its mass is 2–3 times that of the Sun, but only about 10 km in diameter. A neutron star should theoretically collapse into a black hole, but this does not happen. The reason for this, it has been discovered, is that neutrons that cannot share the same position prevent collapse and that neutron stars remain in balance [6].

The universe has been created with balance, and everything, from the minutest particles to the stars in the outer space, follows their particular courses to maintain the order.

References

1. scientificamerican.com/article/identical-twins-exhibit-d/
2. https://www.sciencedaily.com/releases/2009/07/090715131449.htm
3. lbl.gov/2017/listings/contents_listings.html
4. wikipedia.org/wiki/Wolfgang_Pauli
5. phy-astr.gsu.edu/hbase/uncer.html
6. phy-astr.gsu.edu/hbase/pauli.html

Every soul shall have a taste of death (Quran 3:185). Like everything else, stars live and die. Would it make any difference if you knew that the iron in your blood and the calcium in your bones had been assembled inside stars? Atoms heavier than iron are formed by rapid nuclear reactions that can only occur when a massive star explodes. Gold, which is not crucial for our lives, and iodine, which is important for our health, are available, thanks to the violent deaths of massive stars.

The death of a star leads to one of three final states. Most stars, including our Sun, will become white dwarfs, stars about the size of the Earth, with no usable fuels. But the most massive stars explode and leave extraordinary objects behind; either a neutron star or a black hole.

The Sun resists its own gravity by generating energy through nuclear fusion. Under extreme conditions, four hydrogen atoms are combined to form a helium atom, and the mass difference between these atoms are converted to energy which can be calculated by Einsteins famous equation, E=mc², where m is the amount of mass converted to energy and c is the speed of light. In 4.5 billion years, the Sun will exhaust the fuel, hydrogen and helium stored in its core. This will start the chain of events that will result in its death. Since it will not be able to generate any energy to balance the huge weight of its outer layers, it will collapse. This will result in an increase in the temperature around its core. This temperature increase in the shell around the core will start new reactions which will produce excess amounts of energy. This extra energy will cause the Sun to expand and become a red giant. Its size will increase to such an extent that it will swallow Mercury and Venus, and maybe even our planet, Earth. As a giant star, it will have a strong solar wind that carries gas into space. Eventually, it will lose its outer layers, and produce a beautiful planetary nebula.¹ Soon the remains of the Sun will collapse and form a very compact object; a white dwarf. Imagine squeezing the Sun into a planet the size of the Earth. Gravity on a white dwarf is 10 million times greater than it is on Earth. Thus, a person weighing 150 pounds will weigh 1.5 billion pounds on a white dwarf. The white dwarf will burn 100 times fainter than our Sun; if the Earth survives the red giant phase, it will fall into a deadly deep freeze, and would not be a pleasant place to live.²

Medium mass stars, like the Sun, die relatively quietly as they exhaust their fuel and form white dwarfs. In contrast, massive stars live spectacular lives and destroy themselves in violent explosions. Massive stars have too great a mass to die as white dwarfs. They consume hydrogen and become red giants, but unlike the medium mass stars, their core temperature is high enough, about 1 billion degrees, to ignite carbon fusion. After they fuse carbon, they burn oxygen, neon, and magnesium to make silicon and sulfur, and then the silicon fuses to make iron. Iron is the most tightly bound of all atomic nuclei. Nuclear fusion is able to produce energy by combining less tightly bound nuclei into a more tightly bound nucleus, but iron is the limit. Once the core of the star has been converted to iron, there are no nuclear reactions that can burn iron and release the energy. Thus, the iron core is a dead end. The iron core sucks energy from the rest of the star. Since the star cannot produce any energy, it cannot resist its own gravity. In a fraction of a second, the star collapses in on itself. The collapsing core of the massive star quickly becomes a neutron star or a black hole. This collapse happens so rapidly that our most powerful computers are unable to predict the details. The envelope of the star collapses and bounces back off the dense core, which triggers a violent supernova explosion that expels the outer layers of the star to form an expanding supernova remnant. This explosion enriches the neighboring media with iron and other metals. If you throw a water balloon at your friend, your friend will get wet. Massive stars are not water balloons, but they are iron, silver, and metal balloons. When they explode, they seed the interstellar medium³ with metals. If there had not been a massive star death near our solar system when the Sun and the Earth were forming, our solar system would be iron-poor, and we would not be living today. Massive stars die so that we might live. The Quranic verse We have sent down iron, with its mighty strength and diverse uses for mankind (57:25) sheds light on this fact 14 centuries before it was discovered. Only in the past century, with the utilization of modern telescopes, have we had evidence of this. Nursi explained the above verse as iron is sent down together with the globe of the Earth from the Supreme Treasury, as a tremendous bounty. That is to say, the thing most necessary for the house of the Earth is iron, for when the All-Glorious Creator separated the Earth from the Sun and sent it down for mankind, He sent down iron together with it, and met most of mankinds needs with it. The All-Wise Quran decrees in a miraculous fashion: Use this iron in your works and try to excavate it and take advantage of it.⁴

A neutron star, on average, is 1.4 times more massive than the Sun, and is compressed to a radius of about 6 miles. Its density is so high that matter is stable only as a fluid of neutrons. An atom is mostly empty space. The nucleus of an atom is very small compared to the size of the atom. If we represent the nucleus of an atom with a blueberry, then the distance between the nucleus and the electrons would be as great as the height of the Empire State building. If you could eliminate the empty space in atoms, you would be able to squeeze stars larger than the Sun into a radius of about 6 miles (the radius of a neutron star). A neutron star spins several times a second, and has a magnetic field a trillion times stronger than that of the Earth. Observational evidence for neutron stars was first found in 1967 when astronomers found a neutron star (pulsar) rotating around itself in 1.3 seconds and sending radio pulses to Earth. If you have a large enough antenna, you can pick up periodic radio signals from pulsars. On Earth, a teaspoon of the material from a neutron star would weigh 100 million tons.

Another scenario for the end product of the death of a massive star is a black hole. When the core of a star contains more than 3 times the mass of the Sun no known force can stop it when it collapses. The object will not stop collapsing when it reaches the size of a white dwarf or a neutron star, because the electrons or neutrons cannot support the weight of the star. The object will collapse to zero radius (or almost zero radius) and form a black hole. Objects need high speeds to be able to leave another object, to be able to resist falling back due to the gravitational pull of the other object. For example, a space shuttle must reach a speed of 11.2 km/s to to be able to leave the gravitational pull of the Earth in order to go into space. Gravity is so strong near black holes that the escape speed from a black hole is greater than the speed of light. Thus, even light cannot escape; this is the reason why these phenomena are called black holes.

As an object collapses, its gravity increases. If it collapses to zero radius, its density and gravity become infinite. Such a point is called a singularity. Clocks slow down near a singularity. If we were able to watch a person falling into a black hole, we would see them moving more slowly as they came closer to the black hole. In fact, the person would never disappear from sight. From where we were standing, this person would fall more and more slowly, until finally they would hardly seem to move at all. Generations later, our grandchildren would be able to look at this friend approaching the black hole, but never crossing the event horizon (the boundary of the black hole). Black holes are not giant vacuum cleaners that will pull in everything in the universe. A black hole has a huge gravity pull, but its force is quite small if you are not near it. If the sun were replaced by a black hole of a similar mass, the orbits of the planets in our solar system would not change at all. The gravity of a black hole becomes extreme only when approached. There are many black holes in the universe, but they do not pose any threat for us as long as we stay away from them. Next time you advise your children to stay away from strangers, remember to tell them to stay away from black holes, as well.

Footnotes

1. A planetary nebula is an expanding shell of gas ejected from a star, and it has nothing to do with planets.
2. Seeds, M.A., Horizons: Exploring the Universe, 2002, Brooks/Cole
3. The gas and dust between stars.
4. Nursi, S., Flashes, Sozler Yayinevi, 28th Flash