So much pop music is about feelings.
Feelings are great, but so are more objective truths and what could be more awe inspiring than the findings of science. Whose jaw doesn’t drop when considering the size of atoms, the age of the universe, the mind-bending consequences of quantum physics, or the diversity of species all descended from a common ancestor.
If more pop music was about science we might all be a bit more informed and a bit more respectful of our planet. Or we might not. Who knows? Someone should do an experiment.
Heisenberg's Uncertainty Principle
Quantum physics emerged in the early part of the 20th century. Once Einstein had showed that light behaves has both a wave and a particle, it made sense to ask whether particles like electrons might behave as waves. Experiments showed this to be true but the ramifications of producing a model to explain this led to a ridiculously confusing branch of physics known as quantum physics.
It seems that whether a something behaves as a particle or as a wave depends on how you measure it but the more accurately you measure one aspect of the particle e.g. it’s momentum, the less accurately you can measure a different aspect, e.g. it’s position, because your measurement will affect the particle. This relationship was described by Heisenberg’s Uncertainty Principle. Heisenberg stated that it wasn’t just a problem with our ability to measure the world but a fundamental property of the universe itself. As such we can only describe the world in probabilistic ways.
Nobody really understands why the world behaves like this but this description of the universe has stood up to every experimental test we can throw at it and without it we wouldn’t have much of the technology we rely on today.
In the 1930’s we thought we knew all the tiny particles that existed, which were those that made up atoms – electrons, protons and neutrons. We were wrong! After finding a couple of mysterious particles caused by cosmic rays in the upper atmosphere, it became clear that at higher energy levels, other particles might exist. So we started smashing atoms together in particle accelerators, machines that use electric and magnetic fields to speed up particles to close to the speed of light.
The funny squiggles in the picture are trails of bubbles formed by particles in the debris of these collisions. They can be used to calculate the mass and charge of these particles. We soon discovered so many different types, our list became known as the particle zoo. Eventually it was realised that many of these particles were not fundamental but were made of smaller particles called quarks.
We now organise all the particles into families. Particles like electrons are fundamental and known as leptons. Particles like protons and neutrons are called hadrons and are made of quarks. We can now describe all known laws of nature, with the exception gravity, in terms of these particles. This description is known as the Standard Model.
If we compare the amount of stuff we can see in a galaxy with the rate it spins, it should spin itself apart, which means that there should be no galaxies in the universe. There are roughly 100 billion. Something is wrong! There must be more gravity than can be accounted for than what we can see.
This problem led physicists to hypothesize the existence of dark matter, stuff that we can’t detect as it does not reflect, absorb or emit light, but nevertheless has mass. Their calculations suggest that there should be roughly 4 times as much dark matter as there is matter out there. We can see its gravitational effects but we just don’t know what it is. To make things more confusing, cosmologists added up all the matter and dark matter in the universe and concluded that the expansion of the universe should be slowing down. When they measured the rate of expansion of the universe, it turned out it was speeding up. They put this down to an even more mysterious substance called dark energy. So now we know that when cosmologists use the word dark, they really mean that they have no idea what is going on!
Evolution of Man
Although it is very difficult to find evidence about all the steps we took to become the wonderful species that we are today we can look at genetic evidence, evidence from the fossil record, use zoological knowledge of the species alive today and even try to recreate the conditions of the early Earth in the lab to try to work out what species would have existed on our branch of the big family tree of life all the way back to the common ancestor of all life on earth.
Who knows what the future will bring?
Our predictions of how technology will affect our lives are usually wrong, although Back to the Future 2 was not far off! This attempt to describe the future will almost certainly be way off.