Welcome to a new series of posts that will characterize 1000 amazing facts about the Universe. There is so much out there that we have yet to learn, and every day, astronomers across the globe are using their research to reveal the deepest secrets of the cosmos. This series will look at the strangest, coolest, most exciting facts that we have discovered in hundreds of years of modern science.
Fact #3: The Universe is made of a ridiculous amount of nothing.
What is everything made of? The answer will change depending on how much education you have. For most of us we get as far as atoms, consisting of a nucleus made from protons and neutrons, and a surrounding shell of electrons whizzing around. If you went through a bit more depth in nuclear chemistry, you might have learned the quantum mechanical view of an electron, which is a cloud of probability. You may have also found that the protons and neutrons are actually made of tinier particles called quarks, and that there are six kinds (flavours).
Quarks and electrons make up atoms, which form molecules, which cluster to form nebular clouds that collapse into stars and form rocks that become planets and eventually everything else we see on the Earth. It’s expected that the universe started out with about 1080 Hydrogen atoms, raw materials for what is here now.
But when we think of atoms making up a material, we tend to think of billions of them packed together like beads, giving characteristics to everything from human cells to rocks to metals and clothing and everything else that makes up our world. But how do atoms ‘pack’ together? It turns out that they don’t really push on each other in the conventional sense, in the way one would push on a wall. Atoms are mostly empty space.
Atoms are like vast empty football fields, with the nucleus being a tiny marble in the centre. The next atom is another football field next door, and it goes on and on and on. What distinguishes each atom is the number of protons, neutrons, and electrons they have. Atoms are mostly made of nothing, so how can they interact to form materials?
The answer is forces. There are four fundamental forces in nature, known as the Gravitational, Electromagnetic, Strong Nuclear, and Weak Nuclear forces. So an atom therefore is simply a pattern of forces that remains balanced or stable (at least for the stable isotopes), and different atoms represent different patterns of these forces. We only really encounter the first two in human experience, and the other two only really work on the nuclear level and are not fully understood.
We know what gravity is, but strangely it’s the weakest of the forces by far, and as far as we know it has no effect on the structure or stability of the atom. It seems to only work on larger scales.
The electromagnetic force is what you feel when you open a door, put your foot on the floor, or sit on a chair. The atoms of your hand repel the atoms of the wall due to electromagnetic forces. Without the electromagnetic force, you could put your hand right through a wall, though it wouldn’t matter since your body couldn’t keep its individual atoms together without it anyway.
Materials made of atoms are really just macroscopic versions of patterns of forces, and it’s the patterns that determine each specific element and how it interacts with other elements. So the universe is basically a whole lot of nothing using forces to interact with a lot of other nothing. Where does the ‘something’ come in? Earlier we looked at the protons and neutrons being made of quarks, but what are quarks? Could they be ‘something?’
This is the problem. Right now, we don’t know. As far as we do know, they are simply point particles, with no spatial extent. Maybe there is no ‘something’ that makes up the universe, and the universe really is made of nothing.
To summarize, we have 1080 Hydrogen atoms made of quarks and electrons which are essentially nothing, that have formed all the things in the universe that we perceive as ‘something’ through the interaction of fundamental forces.
The fundamental questions then become: What are the forces? Are Quarks and Electrons made of something that is just too small for us to measure with our current technology? What is the Universe?
Whatever the answers are, we find ourselves locked into cosmos that is vast and empty, and all we can do is enjoy the relatively dense collection of atoms that we call Earth.