Mad as a Hatter

Woke up this morning thinking about gravity. It happens.

In particular, I was thinking about the "rubber sheet" model of gravity. The idea is that what gravity really is is a bending of space-time. Imagine a stretched-out rubber sheet. Like, say, a trampoline. Let's say that trampoline represents the universe. Or, rather, the two-dimensional surface at the top of the trampoline represents the universe.

Now, what happens when you put a weight somewhere on the trampoline? Gently, mind you. I'm not talking about bouncing it up and down. You put a weight down slowly, and the trampoline sags under it. Any other object on the trampoline's surface will naturally begin to slide towards it. And the closer you are to the weight and the heaver it is, the more the other object will be drawn in that direction.

That's what gravity is like. Mass bends space-time. The more mass there is, the greater the effect. And the closer you are, the more you feel it.

The thing is that the effect goes on infinitely in all directions. It drops off exponentially with distance, but it's still mathematically there. The same thing happens with, say, a lightbulb. The amount of light you see from it drops off exponentially the further you get from it, but the light rays go out from it infinitely in all directions. Even if you get far enough that it's too dim for your eyes to see, more sensitive equipment can still theoretically pick it up.

All of which is pretty cool because, among other things, it means that you, just by existing, are bending space and time around you in a way which can be felt across the entire universe. And every time you move, you're changing the curvature of the universe.

But it also means that if you know the exact shape of the gravitational field at a given point, down to the nth derivative, you can theoretically extrapolate from that the shape of the entire universe. Which means you'd know the mass and location of every object in existence. By studying exactly what's right here (wherever your "here" may happen to be), you can know where everything in the universe is.

The same goes for magnetic fields. They extend infinitely across the universe, so if you the exact shape of the magnetic field where you are, you could figure out where everything with any kind of electromagnetic charge is.

So, if you were looking for a specific distant object with a magnetic field and you could either know everything about that object's magnetic properties or know everything about the field where you are, you'd be better off with the latter. There are all sorts of electromagnetic fields coming from every direction. Knowing what you're looking for won't help so much because the effects would be miniscule. More importantly, you'd be getting interference from everything else. But if you know the field where you are, you can extrapolate from that where everything is.

I was thinking about that, and I suddenly realized something.

In Robert Jordan's Wheel of Time series, someone with the proper knowledge and sufficient magical power can Travel, opening up a Gateway from one place to another. The thing is that to do it you have to truly, deeply know the place where you are. Not where you're going. Where you're leaving from. You have to really study it. It can take days.

It always seemed like an odd magical quirk. A whim of the writer. But today it clicked for me. It's true. When you're dealing with the fabric of the universe, it really can be more important to know everything about where you are.

ETA: "Every time you move, you are changing the curvature of the universe." This might explain why it's so hard to get out of bed in the morning.

In no particular order...

1. Was in the shower earlier this week^* when I noticed something odd. Some soap bubbles had gathered on the back wall of the shower (as soap bubbles are wont to do). The odd thing was that they were in a familiar shape. Hebrew letters. Four of them, relatively well formed and in a line. Turns out they even spelled a word. Kinda cool, kinda freaky. Less so, however, when that word happens to mean "the board." (Which can refer to a wooden board, chalkboard, calendar, or several other things along that line.) There was possibly another word underneath it, but it was too faded by the time I noticed it. Wonder what it means.

^*Yes, I've showered since then, but that's not important right now.

2. Have you heard of The Coffee Party? It's kind of a reaction to The Tea Party movement (which encompasses a number of organizations, not all of which get along with each other). But kind of not. Actually, it's still figuring out what it is, really. Mostly, it's supposed to be a place where everyone can come together and have a civil political conversation without all the anger and polarization that have taken root in our culture these days. But it's also a reaction to the far-right Tea Party, and, as such, seems to be attracting far more liberals than conservatives so far.

Thing is that both the Democrats and Republicans have been purging their ranks of moderates, choosing to focus more on core values. There is something to be said for dropping people who are ostensibly included in the party but not helping to move the agenda along (or actually actively hurting it). But there's also something to be said for having a big tent and more constituents.

And if both sides are getting rid of moderates as everyone becomes more polarized... those who actually are centrists will be squeezed out entirely. Furthermore, the government becomes even more broken as Congress loses the people who are willing to work across party lines to actually get things done. (As you can see from the current Republican caucus, which seems to be devoted entirely to obstructionism, name calling, outright lying, rank hypocrisy, and generally doing whatever it takes to destroy anything the Democrats want even if it would actually be good for the country.)

So I hope the Coffee Party movement actually solidifies into something that can bring us back together.

And I'm wondering if all of this will mean that we'll actually have a viable third party picking up the centrists squeezed out from both sides.

3. zorkian pointed out this journal, which points out that LJ silently introduced a bit of code that was rewriting affiliate links. So if you posted a link to Amazon that would get you a small commission for the sale, LJ would quietly edit it so that someone else (presumably tied to LJ) got the money instead. The code has since been taken back down (with LJ making vague claims that it wasn't working as intended or something), but this isn't the first time they've tried to just quietly get away with something (and then, when caught, pretend that no, no, they didn't mean that at all).

In a related story, I still have a good number of DW invite codes. You can automatically crosspost to LJ. And soon you'll have the option to read entries from your LJ flist on your DW reading page. All sorts of other neat things, too. Oh, and scans_daily is on DW now, too. Just sayin'.

4. Start with a simple steam engine. The sort of thing that's been around since the early 18th century. A heat source sets a pot of water to boiling. The pressure of the steam drives it through a pipe to a turbine. It spins the turbine, which basically converts the heat energy into mechanical energy. The steam condenses back into water, which is returned to the boiler to start the cycle again.

That gives you a rotating axle, which can be used to power just about anything. You can attach it to a lathe, which can make pipes and screws and all sorts of parts and tools. You can use it to drive a hammer or a grinding stone. You can attach it to a paddle wheel and move a boat. You can put a gear on it and use it as a motor to drive a train or a car or whatever you want.

Or you could hook it up to an AC generator. Spin a wire between two magnets (or spin the magnets around the wire), and you can generate electric current. It really is that simple. You can build one at home if you want.

So we've got a pot of water that boils. The steam drives a turbine which spins a wire and that generates electric current.

How simple is that? And yet, it's how we get the vast bulk of the electricity that powers our modern world. The only difference is that we've scaled it up to the size of a large building. And we've swapped out the heat source. Some places, we still use coal, it's true. Others, it's oil. In many places, though, it's something else - a nuclear reactor.

So what's a nuclear reactor?

Start out with a rod of plutonium or uranium. Elements with large atoms. Large enough that they're unstable. The protons in the nucleus repel each other, and with so many of them packed in, it doesn't take much for some of them to start flying off. Which is why those elements are radioactive.

Now, shoot a stream of protons at the rod. There's a lot of empty space between the atoms that make up the rod, and the atoms are all moving around within the rod, but they're also reasonably large targets and there are a lot of them. Eventually, you'll hit an atom. A glancing blow will knock off a few stray protons. A direct hit can cause the whole thing to come apart in chunks. Either way, you've sent a number of particles flying off, and some of those will hit other atoms, which will send off more particles, and so on, in a chain reaction.

The thing is that each time that happens, a tiny bit of mass is lost. Every time an atom is blown apart, the sum of the pieces will be slightly smaller than the mass of the original atom. What happened to that little bit of mass? Well, according to the theory of special relativity, mass is just supercondensed energy. E = MC². Energy equals mass times the speed of light squared. So the teeny fraction of an atom's mass lost in the fission reaction is converted into a much bigger quantity of energy.

That energy is used to... boil water. Unfortunately, the steam carries with it radioactive particles. So instead of just using the steam from the reactor directly, it's used to heat another tank of water, and the steam from that is used to drive the turbine that powers the generator.

Of course, the reactor doesn't use just one rod. There's a whole grid of them. And in between the rods are more rods, these made of carbon. The carbon rods can absorb some of the particles flying around, keeping the reaction under control (which is why they're called control rods). Basically, they act as the brakes.

So, first off... A nuclear power plant is a really simple steam engine driven by a fancy heat source. Which kind of blows my mind whenever I stop to think about it.

The other thing, though, is that it's incredibly inefficient.A modern high-efficiency coal power plant is lucky to have 50% efficiency - that is, half the energy released from burning the coal is ultimately converted into electricity. The rest is wasted. Lost to friction, to cycling the water, to waste heat. And that's considered really efficient. A nuclear plant is even less so. You blow apart a huge atom. A very small portion of that gets converted into energy. And even that has the brakes put on it because of the control rods. That energy is used for the relatively inefficient task of boiling water. Which is used to boil more water. Which is used to drive a turbine. There's a huge chunk of energy lost at each step. The only reason it works at all is that the multiplication factor of the speed of light squared is literally astronomical.

Not only that, but in the end you're left with the spent fuel rods - which are still highly radioactive. Still composed of large atoms just waiting to fall apart.

And yet, at the beginning of the 21st century, this is pretty much the height of power-generating technology. A steam engine driven by an almost criminally wasteful boiler. You'd think we'd have figured out a better way by now. There's got to be one.

So I was IMing with beansideirae and the concepts "Grandfather" and "Silly putty" happened to sort of come up on one line.

I put them together, wondered what the grandfather of silly putty was, and came up with...

Ooblek!

Which drove her nuts because she had no idea what I was talking about and was afraid to click on the links I pulled up. Finally, I relented and explained, but not before turning up a few YouTube videos about it.

First of all, this one is pretty basic. It explains (without any sound) how you can make ooblek and some of what you can do with it.

Then this kid explains it with less information and more cuteness.

These guys... I don't know what language they're speaking (Silly Putty Val Clar whatever her name is says it's Spanish, which I don't speak, and certainly not at that speed)... they have some fun with it.

Oh, and you can do weird stuff to it with soundwaves. (WARNING: lower or mute your speakers)

All sorts of stuff. There are more vids linked from those. Several of which are basically, "So, hey... I saw this YouTube vid about this stuff, so I thought I'd play around with it and make my own. And then post a video of it to YouTube to inspre five more copycats. Because I'm cool like that."

Anyway... it's cool. And maybe, with my nephew staying over, we'll make some tomorrow.

Even if not, come on. It's fun to say.

Ooblek!