Schrödinger's Kitten

Irreverent Science for Everyone

Thursday 10 April 2008

How The Universe Is

  • quantum
  • macro
  • boggle
  • universe

I apologise for the overuse of really, lots and very in this piece. Anyone wishing to buy me a thesaurus may.

The universe is mostly nothing. On a galactic scale, it is, indeed, very big. And the lumps of planets and stars in it — even though these are indeed mind-bogglingly big, even when compared to things like Westminster Cathedral, frinstance — are very very rare and very very tiny, relative to the massive amounts of nothing in here. This is the same no matter what direction you look in: just light-years of nothing punctuated by the occasional fiery ball of gas, or a speck of rock. It’s all rushing away from us (maybe Earth smells, or something), spreading out in every direction, so the amount of empty space versus the amount of actual stuff is even increasing. Even if you just look at one of the rocky bits; my favourite rock, our rock, the Earth, really closely... it’s still mostly nothing.

If you look as close as you can with the best technique we have, you are rewarded with the sight of a dot in empty space. A lot of empty space. 99.99999999% empty space. This is hard to get your head round. In fact if you can, please go and study physics. For the rest of us, imagine the last time you were in a really crowded place. The tube, a bus, a train, Christmas shopping — something like that. All the sweaty, voluminous masses of people. If you took all the actual stuff in them — take out the spaces – they’re smaller than a grain of sand. However, if you take all the people packed together in the entire city, packed like cattle in their moving tins, or milling around in shops, and do the same — they’re, um, still smaller than a grain of sand. Even if you do this in Japan, or one of those other really really population dense countries — grain of sand still wins. In fact, you can do this to everyone in the world. Simultaneously. 6 — approaching 7 — billion (6,000,000,000; there are 9 zeroes in a billion, thanks to our American friends) people. Many. Lots. And when you take out the gaps between them, they – just about approach the size of a grain of sand. Right? Really very much nothing. Lots of nothing.

But supposing you do look at the bits you have got. As closely as you can. Using some super-duper microscope. What are they? Um, they’re points. Really really small points. Doesn’t matter how much you poke at them, they’re just — little dots. However small you go, they’re still not measurable. Just little blips in the otherwise empty space. And they all look identical, because really, how different can you get in the space of one pixel, say?

But, they are different. In some kind of way. Some of them attract each other, some of them don’t, some of them require much more effort to move them anywhere. Some of them only travel at one speed. Despite all looking like dots. Some of them refuse to do the same thing as any others of the same type. Some of them explode when they hit others. They are different. Somehow.

But, um — they’re all the same. You grab an electron — yes, the things that make electricity when they move, those. They are quite common. And you grab any other electron. And they’re identical. Like, they both have a charge of 1.602 176 4 x 10-19 C1. To that many decimal places, yes. They both have a mass of 9.109 382 x 10-31 kg1. Yes, that is very small. But yes, we have measured it. Trust me, I’ll explain later if anyone cares. And you can grab any others, and none will differ in any way. And all the other types — are exactly identical. What are the conformist buggers playing at? How do they know?

Despite everything being empty space, you still can’t walk through tables (I did try this, when I found out). This is because all the little points mentioned above have Views on where they want to be. And they exert these Views, and repel some points and attract others, though the medium of, um, empty space. Nothing in it. And yet, if you put something in a certain place, a certain distance away, it receives a push that depends on how far away it is and what number it has decided upon for its mass (remember they all look the same, it’s not ‘how big/heavy it is’. It’s just a magic number attached to it). From nothing, yes. These are fields. They do seem nonsensical, however we can’t explain them so we’re just putting up with it.

The whole putting things in a certain place is a bit traumatic, though. Even though when you examine them, they’re little points, when you’re not looking at them they’re more like a cloud of possible places they could be. But when you look at them again, they’re in one place. Just, not necessarily the one they were in last time. So they moved, right? You find out how they moved, they can’t just teleport. But, um, they’re also a cloud of possible speeds and directions of movement, if you want to look at it like that. They aren’t willing to commit to those either. In fact, if you look at where it is, you can’t tell how fast it’s going or what it’s doing. And if you know what it’s doing, you can’t tell where it is. Sorry. If you are still with me, you are doing better than Einstein on this point, although admittedly he didn’t have it explained by me.

Except, sometimes, they can teleport. If you accept that you’re not going to know exactly where they are, and just put them in a pen, with sides they can’t get over — imagine it as a hole with very steep sides, and they can’t get up enough speed to go up the sides – they still don’t stay where they’re put. There is a chance they will escape. And if you wait long enough, even things that have a really low probability will happen, so if you wait ages they will escape. Because as previously stated, they’re not actually in one place, they’re spread out as a cloud of locations, and the cloud of locations — goes beyond the walls. So, um, their location can also go beyond the walls.

Yes, I know. I know. This is why I study physics, to pin those points down and make them behave sensibly.

1. 2006 CODATA recommended values

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