Thursday 13

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Thirteen of my favourite numbers:

1. Negative numbers

Not a number as such, but a whole substrata, and yet, despite being just as prolific as the positive numbers and indeed being identical to them apart from their minus sign accessory, they get nowhere near the same level of attention and are sometimes actively discriminated against.

For instance, how many times have you seen a quiz show where the host will ask a question like "What's the square root of 81?" Of course most numbers have two square roots (and three cube roots, but then things start to get complex). Anyway, because of this, I usually feel obliged to shout out "-9" at the television in support of that infinite minority of negative numbers (I used to shout out that the question itself was erroneous in its premise but that was a bit long-winded and made me even more unpopular with those watching television with me than merely shouting out negative numbers does).

2. Zero

Not positive, not negative, possibly the most apathetic of numbers. Still, while it doesn't seem to amount to much, and having zero dollars in your bank account is fairly depressing, start shoving those zeroes after other numbers and things look a lot rosier.

Having said that, the reason I like it is that it's the only number with one square root, so it saves me shouting at the television.

3. One

Why do I like one? Well, mainly because one is the loneliest number, so I figure it needs all the friends I can get.

4. Two

Why do I like two? Well, it's the loneliest number since the number one, so again I figure it needs friends.

5. Euler's Number

Well, it lets me call it e. Sure it can be irrational at times, but if you differentiate e to the power x you get e to the power x so that's kind of cool.

6. Pi

The ratio of a circle's cirumference to its diameter. I like it because it sounds like PIE. Also, it's had a film named after it, unlike so many other numbers.

7. Thirteen

Where would I be without the number 13? Doing another meme, that's where. Sure, some people think thirteen's unlucky, but being a Hitch-Hiker's Guide To The Galaxy fan, I quite like the fact that in base 13, six times nine does actually equal forty-two.

8. Thirty-Six

Sure, it might look like a square, but it's the highest number on a roulette wheel, and if you add up all the numbers between 1 and 36 you end up with 666, the Number of the Beast.

9. 789

It reminds me of the hilarious joke:

Q: Why do all the numbers fear 7?

A: Because seven ate nine.

10. 1729

Long, long ago, in the mists of time, back when I was at University, a lecturer told us the tale of some famous mathematician of the past (I sadly forget the mathematician's name). Anyway the mathematician and his friend were talking and for some reason the number 1729 came into the conversation (maybe that was the year, maybe they were discussing PIN numbers, maybe it was almost half past five, who knows). "1729," said the mathematician, "there's an interesting number. It's the sum of two cubes - twelve cubed (1728) and one cubed (1) - and also the sum of another pair of cubes - ten cubed (1000) and nine cubed (729)."

Now, you can't get much more interesting than that, can you?

11. Avagadro's number

Picture the scene. It's the past and Euler walks into the bar after a long day at work and reveals he's been building a number.

"How big is it?" asks the guy at the end of the bar.

"2.71828 18284 59045 23536 or thereabouts," replies Euler.

"What?" says the guy, laughing. "That's less than Pi."

As Euler walks off in a huff, Max Planck enters. "Hey, I've just come up with a new constant."

"Is it big?" asks the guy at the end of the bar.

"Nein," says Planck, suddenly realising he's German, "Es ist sehr kleine."

Just as the guy's about to burst out laughing, some astronomer or other rushes in and says he's measured the speed of light at 300 millions metres per second."

"That's nothing," says the guy at the end of the bar. "My name's Avogadro and I spent the day counting the atoms in a mole. Something like 6.022 times 10 to the power 23."

It's possible that this story's apocryphal, and even more possible that I just made it up, but regardless of those things, Avogadro's Number is really, really big, and you've got to respect that.

12. Googolplex

A googol, as you no doubt all know, is a one with a hundred zeroes after it (there's a one that's not a lonely number). Following on from that, a googolplex is a one with a googol zeroes after it, and is more than the number of the atoms in the Universe (or so I seem to remember Carl Sagan saying on Cosmos once). It laughs at Avogadro's number.

13. Aleph Numbers

Let's finish, as we began, with a bunch of number. Once upon a time, I spent a term at University doing Logic and learning about levels of infinity, and cool numbers like Aleph-null and Aleph-one. What I discovered the next year was that I could have learned exactly the same things just by reading Rudy Rucker's White Light. Anyway, I can see I've started to send you off to sleep already (and myself too for that matter) so I'll spare you the gory details (if you're really interested please feel free to ask).

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