5
All 6 Billion People On Earth Can Fit Inside An Orange
If I can just be allowed to explain, 99.9% of an atom is just empty space. “Well heck, everyone knows that!”, I hear you cry. As is the case with many facts we tend only to recognise this point in theory, because we cannot really envisage what an atom is like to look at. It is very small.
To put this point into perspective, if you removed all the empty space from the atoms that make up all the humans on the planet then you could fit all 6 billion of us inside a single orange. Come to think of it some unkind people have called me a waste of space and now it’s provable!
We can find atoms everywhere, since they are among the fundamental building blocks of the universe. The Sun contains 99.86% of all the mass in the Solar System. The mass of the Sun is approximately 330,000 times greater than that of Earth. It is almost three quarters Hydrogen, whilst most of the remaining mass is Helium.
You see where I’m going with this? That means that the sun is responsible for most of the solar system and we account for no more than you could fit in the palm of your hand. Literally.
Atoms are on the very threshold of super-weirdness. They are stupidly small, yet account for just about everything in existence. One single strand of gossamer thread has about 1 million atoms across its diameter. Its mass, or the 0.1% of it that is actually material, is concentrated at its centre and is something like 1 trillionth of a centimetre across. Its electrons fly around the remainder of the space it occupies at impossible speeds. Even then we tend to rationalise what this means, but if we draw one of those perspective enhancing analogies that help soothe our brains let’s say the nucleus of an atom were the size of a football. At that scale the nearest electron would be half a mile (0.8km) away.
It’s no use. Atoms are just causing me a headache. What we need is another science to explain everything more rationally that doesn’t just cause more headaches.
4
Most Of The Universe Appears To Be Missing
So, let’s take stock of where we are here. We have ascertained that the universe is pretty astounding when considered at a vast scale. We have established that the universe consists of atoms. We have also worked out that atoms contain space mostly and a very tiny amount of matter. Leaving aside the worrying fact that we are made of atoms, how much matter is there in the universe?
According to the Planck mission team, and based on the standard model of cosmology, ordinary matter accounts for a staggeringly minuscule 4.9% of the total. The rest is 26.8% dark matter and 68.3% dark energy. I’m going to obstinately ignore the dark energy, because that’s clearly the equivalent of nothing – it’s not matter in any case. Can dark matter give a bit of substance to our existences?
Dark matter is at present no more than a very strong hypothesis among cosmologists and astronomers. It comes about for the very reason that we need to account for a large part of the mass that appears to be missing from the universe. Yes, I did write ‘missing’ there. The official view is that much of the universe’s matter, 26.8% of it, is simply… not there.
That is not the same as saying that nothing is there at all. There must be something, it is thought and this is clear since discrepancies exist between the mass of large astronomical objects determined from their gravitational effects and the mass calculated from the visible matter they contain. At best, dark matter can be thought of as matter that cannot be illuminated with light. It neither emits nor absorbs light or other electromagnetic radiation at any significant level. At worst, dark matter does not exist at all, but either way there is a significant amount of the universe unaccounted for.
Why are we so sure there is something there? It appears that we cannot just write the ‘matter discrepancy’ off like so much shop stock left unsold at the end of the financial year. The fact is that something as yet undetermined is having a very real effect upon the orbital velocities of stars in the Milky Way and is responsible for “missing mass” in the orbital velocities of galaxies in clusters, (as calculated by astronomers Jan Oort and Fritz Zwicky).
Whichever way you look at it the behaviour of atoms and things unseen in the universe is a complete mystery.
3
Light Doesn’t Always Travel Very Fast
“Nothing travels faster than light.” That’s something we hear bandied about quite a lot. Another is, “Light is a constant. We can measure everything alongside it.” Sometimes we hear that light can have its direction of travel altered, e.g. when it passes close to a star. The truth is that light can end up going quite slowly and it is not quite the constant many believe it is.
What people mean to say, or should rather express, is that light travels at a constant speed in a vacuum. Without this essential qualification we soon see that light is anything but a constant. In a vacuum light travels at 186,000 miles per second, (300,000 km per second).
Am I just a pedant merely quibbling with tiny amounts of speed? It seems not, because when travelling through water photons will slow down to about three-quarters of their maximum pace. That’s a full 100,000 km per second. You can go a long way in one second if you’re a photon of light, so I don’t call that a quibble.
It gets weirder when we start observing light in specific spaces. Particles in some places acting alongside light photons actually go faster than light itself. Does this mean they’re travelling into the future, I wonder?
I wouldn’t like to get into that question, but in a nuclear reactor that is precisely what happens. In a reactor some particles are forced up to extremely high speeds indeed. If they happen to be passed through an insulating medium that slows light down at the same time they end up going quicker than the light around them. When that happens you get an effect called Cherenkov radiation, which manifests itself as a blue glow. Reactors glow in the dark, not because they are getting overheated, but because light is being overtaken.
Scientists have even slowed light down to a standstill and the slowest it has been recorded travelling was 38 miles per hour, (17 m per second).
2
Electrons Colliding At The Edge Of The Universe Affect Us On Earth Instantaneously
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Another simplification of explanations about atoms concerns the ‘billiard ball’ analogy. In this description we are invited to think of all the atoms in the universe like a collection of billiard balls bouncing around against each other. It’s not a bad description, but it does rather ignore the effects of gravity. Gravity is rather more powerful than many suspect.
Take, for example, the World Snooker Championship, which is played out every year at The Crucible Theatre, Sheffield, England. When the champion-elect gets to the final ball upon which the tournament rests, does he stop to consider the fact that every person’s gravitational field in the auditorium is going to affect his shot? No, he does not and neither should he, because the effect of the gravity involved is so very small when just two balls strike each other on the snooker table.
On the other hand if his shot involved a canon, or collision, with up to 50 balls in sequence then he had better alter his style of play, because under those circumstances everyone’s gravity would have a very real effect. Why? It can be shown that the gravitational attraction of a single electron, at the edge of the known universe, (10 billion light years away), is sufficient to deflect an oxygen molecule in the air on earth by enough to miss a predicted destination molecule within about 50 collisions. And it all takes place within around one hundred millionth of a second!
Before you object that this could never be shown to be true this has actually happened in an experiment, although it was across a laboratory rather than an entire universe. It does sort of lend weight to recent theories involving chaos where sensitive dependence upon the initial conditions of the state of a system are highly relevant to its eventual position after a period of time. Mind you, astrologers could equally argue that it gives credence to the stars having a genuine effect upon our lives down here too, I suppose!
1
You Can Never Use The Past To Predict The Future
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At first sight this statement might look like nothing more than an observation about the bleeding obvious were it not for the fact that it hides a deep truth about the structure of the universe.
None of us can predict the future, but Chaos Theory implies that we never will be able to either. For centuries astronomers tried to compare the solar system to an enormous mechanism revolving around the sun – something like a gigantic clock.
Unhappily for them all they found out was that their equations never actually mirrored how real planets would travel across space.
The theoretical difficulty was summed up by the work of French mathematician Henri Poincaré around 1900. He demonstrated that while astronomers can easily predict how any two celestial bodies will travel around their common centre of gravity, by introducing a third gravitating body (such as another planet or the Sun) you prevent a definitive analytical solution to the equations of motion. This makes the long-term evolution of the system impossible, in principle, to predict.
Many suppose that the practical difficulty in predicting the trajectory of the system is a lack of computing power and that one day even this will be overcome. The problem with this approach is that Heisenberg’s Uncertainty Principle rears its ugly head time and again, because the level of sensitivity to the system’s initial conditions involved could actually be relevant right down to a quantum level. We can be sure enough about big events on a grand scale to get us by at a practical level. This has to be so, otherwise no lunar mission would ever hit the moon every time with certainty. But if we want to get really detailed about many things interacting with each other in a system, then the universe may have a found a way to prevent us ever finding out how things will really turn out.
In short, the universe tells us what some philosophers have always guessed – that there is absolutely nothing one can be sure of save the existence of one’s own mind. And at that point I think I had better shut up before someone points out to me the problems with Solipsism.
