About Atoms and the void
The “atoms” that we know are not “a-toms” in fact, in the original sense of the word.
The word “atom” comes from the Greek, where “a” means “no,” and “tom” means “division”.
The original concept of the atom is derived from the ideas of the Greek philosopher Democritus (460–370 BC).
The idea of Democritus was something like this. Take a piece of bread and cut in half with a knife. Take half of the bread and cut again. Continue cutting the bread, infinitely. What is going to happen? You can continue cutting ad infinitum, i.e. the matter is continuous, or you will reach a point where you can no longer cut the bread, and the last piece is indivisible. Call atom this piece of indivisible matter. Does atoms exist or not? Can you can slice the matter infinitely?
Jumping from ancient Greece to High School
The chemistry lesson presents a solution to the dilemma of Democritus: the atoms in the Periodic Table of elements: hydrogen, helium, carbon and others.
These atoms are the smallest building blocks of our world. They are like bricks, from which everything else is built. The atoms form molecules such as Lego little pieces. Water is H20, two hydrogen atoms and one of oxygen.
It is very cool, up to now. The next lesson is that atoms have a nucleus, which concentrates all the mass, having electrons orbiting around. This model resembles the solar system. Moreover, atoms have atomic number, are formed by protons, neutrons and electrons, the number of electrons in the last layer is what dictates how many bonds this atom will form, and so on…
Hence, I raised my hand and asked the teacher of chemistry:
“Professor, if the atoms are made of protons, neutrons and electrons, they are divisible into smaller parts. So the atoms are not atoms in the original sense of the word. Actually, were the true atoms the protons, neutrons and electrons? “
The answer was some incomprehensible, but the final message was clear:
“The entrance exam will ask the questions exactly how I told. Decorate it and stop philosophizing. “
Giving a fast forward of about 20 years, I no longer have to pass the entrance exam, so I can philosophize at will. The best of science is the possibility of questioning everything…
My opinion is that, despite all the advances, the fundamental question of Democritus remains as open today as it was long ago: are there atoms or the matter is infinitely divisible?
Do protons, neutrons and electrons really exists?
The discovery of protons, neutrons and electrons did not occur in the sense of Democritus, cutting the matter with a knife to get the protons. It was by indirect means and to justify results of experiments.
Scientists in 19th century (as J. Thompson — 1856 to 1940) identified that the atom has a particle with a negative electric charge, and called it “electron” (electrons gave rise to electricity).
But the atom as a whole has a neutral charge. Thus, if there is a negative particle and the total is neutral, you must have other positively charged particle to compensate — this particle they called “proton.”
However, only protons and electrons did not justified everything, there was something neutrally charged, it had mass. The called this neutrally charged thing as “neutron”.
This continued until science had a “knife” powerful enough to cut into pieces and analyze bits of atoms — whether by nuclear reactions, radiation or colliding atoms.
Physicists in 20th century, with new tools and new theories such as quantum physics, reported that there are fundamental particles. These have no substructure, they are not composed of other particles, reaching a more complete theory than to just label all that is positively charged as protons and neutrons the rest.
According to the standard model, we have the quarks, gluons, bosons and others — see link for details .
For example, in this model, the electron remains a fundamental particle, but is a type of lepton, which in turn is a fermion …
One of the most intriguing theories of quantum physics says that particles and waves are two faces of the same coin. The light can behave both as a particle and sometimes as a wave. But not only the light, other particles also have this behavior — so these fundamental particles could not really be particles but waves, or be both wave and particle…
The most powerful “knife” nowadays is the Large Hadron Collider (LHC). It lays at the border between Switzerland and France, and has almost 27 km in circumference.
The particles are accelerated in opposite directions, until nearly the speed of light, then the collision is made between the particles. After the collision, the analysis of the fragments (subatomic particles) is made. Obviously, it is not easy to detect and analyze such small particles (or waves?), and even today, a number of elementary particles are merely theories, without experimental confirmation.
These elementary particles are currently the closest concept that exists in the original idea of the atoms of Democritus.
But who guarantees scientists will not find particles (or waves) more fundamental than the current ones? Does a “knife” even more powerful, say a particle accelerator the size of Earth’s orbit, can not keep cutting fermions and muons into smaller “pieces”?
Can we continue cutting the matter, infinitely? The lower limit would be the Planck length of the order of 10 ^ -35 m?
The limit would be pure energy encapsulated? But what is energy, exactly?
The limit would be the smallest possible time (Planck time)? But what is time, exactly?
There is a school of thought that says that philosophy is useless by definition. Because, when philosophy becomes useful, it changes its name.
The Democritus atom is an example. We left the philosophy of Democritus, in which we knew nothing, for successive atomic models of chemistry and physics, where supposedly we knew everything — and we built modern scientific advances with this knowledge.
But in the end, we turn to philosophy again — the size of the “do not know” is immeasurably greater than the size of the “know.” And the question, what is the smallest indivisible unit of matter, is as open as in Democritus’ time.
“There are only atoms and the void” — Democritus.
“I could be bounded in a nutshell, and count myself a king of infinite space, were it not that I have bad dreams.” — Hamlet, William Shakespeare.
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