Gravity and the Theory of Inflation

Back in the January and February of this year, I was fascinated by the beginning of things. Cosmologically, I was exploring the birth of the universe and the idea of the Big Bang, the beginning of it all.

As I near the dark end of the year, however, I find myself becoming more interested in the end of things and the sense of ripeness and death.

I have become aware of new research into the nature of the Cosmic Background Radiation and the relatively new and contentious idea of Dark Flow, heretical ideas that this universe is operating inside something else.

It is a branch of cosmology that is as riddled with paradox and contradiction as quantum physics. Indeed, the phrase “this universe” is, itself an impossible contradiction, because it implies one universe among others, and that makes nonsense of the word “universe”, which means “everything”. You can’t have two everythings!

But, let us start with what is known as the Standard Model. It is also known as the Big Bang theory or creation story, for, in a sense, that is all it is. Another creation myth.

It goes something like this.

Once upon a time, a very very long time ago, about 13.7 billion years ago, there was absolutely nothing, anywhere. There was no where for there to be nothing in, no time, no space, no light, not even any energy.

This is so strange that it is impossible to even imagine it, except as the mathematical symbol 0.

Some hominids, on a planet called Earth, have called this 0 God, or the Void, or the Face of the Deep, or the Great Spirit. Whatever a particular tribe of hominids called it, they always gave it their equivalent of capital letters, and they always thought it was very important.

All of a sudden this nothingness exploded, out of nowhere, as it were. Because there was nowhere anywhere at the time, the explosion happened everywhere and at a miniscule point at the same time, and thus, because this was the first thing that had ever happened, it created time and space and the potential for mobile phones and soap operas and the Andromeda Galaxy at the same moment.

This explosion is known in the scientific community as The Big Bang, and a bang as big as this would need and would release a lot of energy, and all that energy would have made the very early universe very hot.

All explosions are chaotic things, and, although everywhere in this explosion would have burned your toast, the temperature would not have been uniform. Bear in mind, that when physicists talk about the variability of the temperatures just after the Big Bang, they are talking about differences in the order of a millionth of a degree. Primitive organisms like us wouldn’t notice much difference.

Because the temperatures would have varied, the energy and matter created by the Big Bang would have flown off and clumped in irregular clumps, and, like explosions on the planet Earth, the universe would have ended up as a bit of a mess.

But, the amazing thing is, that it didn’t end up a mess. In fact, one of the problems with the Standard Model, was that the universe is too homogenous. Everywhere you look in today’s universe, the temperature is the same, there are no hot nor cold spots, and matter seems to be uniformly spread. If it were not uniformly spread, some parts of the universe would have more mass, and therefore more gravity, than other parts, and the whole shebang would get sucked down a huge black hole, like water disappearing down the plug. To prevent this total destruction, one super-heavy black hole must be balanced by another, somewhere else.

So, a big problem with the Big Bang, was how did it manage to get so uniform?

In order to deal with this problem, physicists including Alan Guth in the 1980s, invented the notion of Inflation. They didn’t invent it like you and I invent things. They didn’t just pluck it out of the left field. They used mathematics, which, they say, is the language God uses. It’s worth bearing in mind at this point, though, that Bertrand Russell, the twentieth century philosopher, claimed that mathematics was nothing but a huge leap of blind faith, anyway!

According to Inflation, immediately after the Big Bang the exploding universe would have had to have stopped expanding long enough to cool down and become uniform, before suddenly expanding by squillions of times to near its present size, which would give us our big, uniform, cool cosmos.

This would also explain the apparent uniformity of the Background Cosmic Radiation, which is the microwave energy left over from the Big Bang, which we can see on our television screens when we watch an un-tuned television channel.

(Bill Bryson, author of A Short History of Nearly Everything, said that, if we felt there was nothing worth watching on television, we could always change channel and watch the beginning of the universe!)

After tweaking the Big Bang with the idea of Inflation, physicists settled down with this as the new Standard Model of the beginning of everything.

However, it soon became obvious that things weren’t as settled as they had at first thought. Some of the observable data didn’t fit the theory of how the universe was constructed, and this was very fundamental, and the change of basic beliefs that it required threw everything previously taken for granted into doubt.

The problem was concerned with certain observable rules about the behaviour of gravity.

Take our solar system, for example. By far the most massive thing in our solar system is the sun. Compared to anything else, it’s really huge, and because of this it has a correspondingly huge gravitational pull on everything else in its sphere of influence. It’s why all the planets, asteroids, bits of dust and gas, don’t just go wandering off into interstellar space. All the planets – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune – are locked into orbit round the sun by its unimaginable gravitational pull.

All this has been known since Newton.

Now, there is something strange about this. Mercury is the smallest planet, weighing in at about one third the size of the Earth, and it is the planet nearest to the sun. The gravitational pull on it must be huge. Why doesn’t it slowly get pulled into the sun?

At the other extreme, Neptune is the planet furthest from the sun, and is nearly four times bigger than earth. The sun’s pull is obviously much weaker here. Why doesn’t it just spin off into space?

The answer lies in the speeds at which the planets orbit the sun.

The Earth goes all the way round the sun in 365 days. This is an Earth Year, and it is obviously determined by the speed the Earth is travelling, which is exactly the right speed to keep it in exactly the right place. If it went any slower, it would just curve towards the sun and be destroyed. If it went any faster, it would rocket off into deep space like a stone from a sling or a hammer from an Olympic athlete.

The same is true of Mercury and Neptune, but because they are different masses and different distances from the sun, the speeds they orbit are very different.

Tiny Mercury goes round the sun in about three months, so it is travelling about four times faster than the Earth. Any slower and the sun would swallow it, any faster and it would leave the solar system.

Neptune, on the other hand, takes nearly 165 Earth years to orbit the sun.

The rule is, the nearer the sun, the faster planets have to travel to maintain their position, and the further from the sun, the slower planets have to travel to stay in orbit.

It is a rule. There could be no planets without it. It is a perfect mathematical balance.

So far so good. Newton knew all this, Einstein knew all this, Brian Cox knows all this.

No problem. Long live the Standard Model.

But . . .

Our sun is one star, not a very remarkable one, in a galaxy of billions of other stars that make up a galaxy known as The Milky Way. Like all other galaxies – and there are billions of them out there – our galaxy is frantically spinning round its centre, just like the planets spin round the sun.

The moon is spinning round the Earth, the Earth is spinning round the sun, and the sun is spinning round the centre of the galaxy. You can see why people imagine it like a piece of cosmic clockwork.

The distances and speeds involved in this galactic roulette wheel are just silly. A galactic year is the time it takes the sun to go once round the centre of the galaxy. Estimates put this time as about 225 million years. Since the Milky Way was formed, it has performed about 54 rotations.

Mind-bending though all this may be, it still conforms to the Standard Model.

But, according to the rules of gravity, that we have seen in operation in our solar system, the stars that are near the centre of the galaxy should be moving faster than stars like ours, that exist on the edge, in what Douglas Adams called the unfashionable part of the galaxy.

However, all the stars in the Milky Way are travelling at the same speed, and this is just impossible. If this was really happening, the whole galaxy would just fall apart, with the central stars being sucked into a massive black hole, and the outer stars, like ours, flying off into the vacuum of space.

But it is happening. And it can’t happen, according to the Standard Model and everything we know about gravity and the nature of the universe.

So, what’s going on?

The only way our ideas about mathematics and gravity can make, or allow, this to happen, is if galaxies were much heavier than we know they are. About five times heavier, in fact.

And the only way they could be heavier than we thought is if there is something or things there that we can’t see or pick up on any of our instruments. Sounds a bit like God to me!? Perish the thought!

I’m sure the Ancient Greeks, faced with this problem, that the observable universe did not conform to the rules of mathematics, would not have jumped to the conclusion that the universe was wrong. They would probably go back to first principles to check if it was the concepts of mathematics that were wrong.

Anyway, all this stuff that we can’t see and has no discernible effect on our universe, apart from the rather important one of holding galaxies together, is what scientists call Dark Matter. The universe just isn’t what we thought it was. At all. For every kilogram of matter in this universe, there are five kilograms of dark matter, doing whatever it’s doing, and totally ignoring us and just passing through what we fondly believe to be important stuff, like planets, and people, and television presenters.

Sometimes, in my arty-farty, metaphorical kind of way, I like to imagine that all this undetectable dark matter is consciousness, or awareness, or creativity.

Whatever it is mathematically, it is all the Dance of Siva, the Hindu god of destruction and creation, and, in the words of the song, you can’t have one without the other.

 

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About stevehobsonauthor

I am blind, and I hate it. It stinks. But life is still sweet. I have multiple sclerosis, and that stinks too, but life is still sweet. These are my musings.
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