Most of Everything is Nothing

After I posted this series of articles about why I assume that reality is basically as it seems after applying reason to the evidence of my senses, I got a nice email from Bob Rees, who pointed out that:

Nothing is what it appears to our puny senses. 99.999999999999 per cent of the volume of ordinary matter, say, a concrete block, is empty space. And even the things we see and touch have to be interpreted by our brains before they ‘mean’ anything to us.

Bob is correct. Everything around us seems to be made up of tiny particles of matter called quarks and leptons, plus huge amounts of empty space, plus invisible substances called dark matter, all being moved around by energy forces like electromagnetism and gravity. 

• Atoms are incredibly tiny. A single grain of sand contains sixty million million million atoms. 
• Quarks are even tinier than atoms. If an atom was enlarged to the size of the planet earth, then each quark at the centre of it would be smaller than a tennis ball. 
• Leptons are even tinier than quarks, if you can imagine one geometric point being smaller than another. The most familiar lepton is the electron.
• Empty space makes up nearly all of every atom. Returning to our imaginary giant atom, you have clusters of quarks, each quark smaller than a tennis ball, in the middle; then a huge sphere of empty space the size of the planet earth; then a cloud cover of tiny electrons around the surface.

Here are some more fascinating details of the tiny particles of matter inside each atom:

Quarks cluster together in groups, called protons and neutrons, which form the nucleus of an atom. The atom is completed when this nucleus is surrounded by a cloud of leptons called electrons. Then huge amounts of tiny atoms combine to form either a millimetre-wide grain of sand in Cairo, or a hundred-metre-high Redwood tree in California, or a medium-sized human body such as yours.

Atoms

Atoms are incredibly tiny. A single grain of sand contains sixty million million million atoms. If you were to count these atoms, taking a second to count each one, it would take you two million million years. Now, that’s not practical, as you would need lunch-breaks and time to sleep and you may not even live for two million million years. So, if you hired other people to help you do this counting, and they all counted non-stop for an average eight-hour five-day working week, without any holidays, then the entire population of the world could spend their entire working lives to count just one twentieth of the atoms in one single grain of sand.

Quarks

Quarks are even tinier than atoms. If an atom was enlarged to the size of the planet earth, then each quark at the centre of it would be smaller than a tennis ball. Quarks are so tiny that physicists treat them as geometric points that do not even have a physical size, though they do have a tiny mass and a tiny electrical charge. Quarks cluster together in groups of three, to form either a proton (which has a positive electrical charge) or a neutron (which has no electrical charge). Some atoms contain more quarks than others: Hydrogen, the lightest atom, has just one proton and one neutron; while gold has 79 protons and 118 neutrons.

Leptons

Leptons are even tinier than quarks, if you can imagine one geometric point being smaller than another. The most familiar lepton is the electron, which moves at over 1,000 miles a second. Each electron has a tiny negative electrical charge, which causes it to be pulled towards any nearby proton, which has a positive electrical charge. Most of the time, an electron is just a tiny cloud of possible locations where the electron might actually be. This tiny cloud surrounds the nucleus of an atom, and tries to get as close as it can to a proton within it. Then the cloud settles at a certain distance away, based on the energy level of the electron. 

Empty space

Empty space makes up nearly all of every atom. Returning to our imaginary giant atom, you have clusters of quarks, each quark smaller than a tennis ball, in the middle; then a huge sphere of empty space the size of the planet earth; then a cloud cover of tiny electrons around the surface. Now reduce this imaginary giant atom to its proper size, so that sixty million million million of them fit into a grain of sand. Then combine lots of these tiny bundles to form stones and trees, ants and whales, tables and computers, planets and stars. And you realise that nearly all of everything is actually nothing. The idea that everyday objects are solid matter is only an illusion.

In a later article, I’ll look at the question of how energy causes these tiny particles to move, and why we don’t fall through the floor with every step that we take. But in the meantime, sit back and marvel at the fascinating worlds with a world that exist within every grain of sand.

Photo: Large Hadron Collider at CERN by CERN (cc)

Postscript: The photo above is part of the Large Hadron Collider project at CERN in Switzerland. Tiny protons are sent hurtling around a 27 km long underground tunnel at almost the speed of light, to investigate what happens when they collide together. For scale, see the man at the centre of the bottom of the main photo.

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