Since ancient Greece, humans have wondered about the material composition… of the material. The philosopher Democritus had proposed that everything that exists was in fact made up of infinitely small and indivisible bodies: atoms. Obviously, Democritus could not scientifically prove the existence of the atom; it was just a guess. His reasoning was: what would happen if you repeatedly cut an object in half? At some point, we would reach the smallest form of matter possible… He baptized this hypothetical object atomswhich means “indivisible”.
We know today that what we call the atom is actually divisible, but Democritus’ explanation is still important in the context of the time. Atoms are made up of particles such as electron, proton and neutron. These last two are even made up of sub-particles called quarks (the electron would indeed be elementary).
According to our knowledge, the visible universe is composed entirely of atoms and particles. Our planet is an agglomeration of atoms. The atmosphere, soils, lakes and rivers are all made up of atoms. And life ! Life too is made of atoms.
The human being is an assembly of billions of billions of atoms carefully harmonized into complex molecules. Our brain, where electrical impulses from our nervous system are interpreted, records and analyzes the data the body gathers about its environment. And strangely, the human brain, itself an assemblage of atoms, has acquired the ability to to understand the atom.
So here’s a question: how many atoms are needed to understand the atom?
The adult human brain has a mass of about 1.5 kilograms. We could, thanks to Avogadro’s number (which measures the quantity of elementary entities that a mole of matter contains), estimate how many atoms there are. The result would be gargantuan: in comparison, a small sip of water of 18 ml contains more hydrogen and oxygen atoms than there are stars in our galaxy!
Be careful, however: the brain alone is not enough. It needs a body to feed itself and develop. The brain needs vital organs to survive, a skeleton and muscles to move, feed and learn. If you take into account that an average adult human can weigh from 50 to 150 kilos, the number of atoms required to understand the atom has just increased considerably.
But that’s not all. The human body and its brain cannot evolve in empty space! They need a planet to live in, air to breathe, water to drink and nutrients to eat. Come to think of it, the whole planet is necessary to understand the atom. The Earth has an approximate mass of 5.97 x 1024 kilos. It was on this agglomeration of atoms that the process of life began almost three billion years ago. Without all this mass, the modern human being would never have been able to develop to understand the atom.
But… hold on! The Earth would be nothing but an insignificant icy dust without the presence of the Sun. Without the energy it provides us, the atmosphere and the oceans would be frozen. There would be no climate to redistribute heat and water over the entire surface of the globe. Without a stable adult star like ours, the chemical reactions that led to life would never have taken place.
The Sun has a mass of 334,000 planet Earths. It alone takes up about 99.8% of the mass of our entire solar system. The atoms of the external layers of the Sun crush, by gravity, those of the core of the Sun. These are so pressurized that they fuse into heavier elements, creating a tremendous amount of heat energy. So if we add the Sun, the number of atoms needed to understand the atom just increases again exponentially.
Except that… stars don’t form in a vacuum! They are the product of the gravitational collapse of nebulae, those large clouds of gas and dust that are ubiquitous within galaxies. The Milky Way, our galaxy, is estimated to contain 100 billion stars. That’s a lot of atoms.
Does it continue? Does the Milky Way need other galaxies to support life? There, I don’t know.
Conclusion: how many atoms are needed to understand the atom? The answer is both simple and disarming: at a minimum, all the atoms in a galaxy. At most, perhaps, indirectly, the whole Universe is required for the understanding of the atom…
But what do I know? After all, I’m just a collection of atoms trying to figure it out.
#galaxy #understand
