Posts tagged with "Matter":

Triple Point

Early on, everyone learns that there are three basic states of matter: solid, liquid, and gas. That's not entirely correct, as there are also fun things like plasma (the fourth state of matter) and not-quite-states like supercritical fluids, but it's correct and reasonable enough for us to go on. Also, usually, we think of these states as existing in a line: solid, at a high enough temperature, becomes a liquid; liquid, at a high enough temperature, transitions to a gas. We imagine these states to exist on a temperature line like so:

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Three Quarks for Hadron Mark

All the matter that is around you is made up of atoms. That's a pretty well-known fact at this point, and, while it gets increasingly interesting and strange the more you think about it (the properties of each different element are just functions of how many protons it has, which is pretty wild), an atom is not the fundamental unit of matter, as its name, derived from the Greek atomos, which means indivisible, would suggest. No, the physicist John Dalton disabused us of that notion back in the 1800s, and since then we have learned that an atom consists of three constituent particle types: protons, neutrons, and electrons. Hans Geiger, Ernest Marsden, and Ernest Rutherford came up with the model of an atom with those pieces (as covered in the very first Fizzix Phriday blog post), and that most of the mass of an atom...

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How Empty is Space?

Oh, man, is space big. I get upset thinking about it sometimes. It's just too big (then again, my general reaction to the largest living thing on the planet, the General Sherman Tree, was to get angry). But it's not that space is just so large, it's also that it's so empty. And that is what I'm here to talk about today.

The visible universe is about 93 million light-years from one side to the other. That means we can see about 46 million or so light-years in any given direction, if we look hard enough (you'd need impossibly good eyes, though, or you could just use a really powerful telescope and also be in space because the atmosphere really gets in the way of seeing that far)...

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A Brief History of the Universe, Part I

Time is a tricky thing. The idea of the Big Bang has become common knowledge, but a question many still have as to the birth of the universe is what came "before" it, or indeed what was the "cause" of the Big Bang. While one might answer these questions with "nothing," that's not really correct, because the answer is actually much simpler and at the same time so much harder to grasp in any intuitive sense. The answer, which I understand intellectually but still makes no sense to me in an intuitive way, is that there was no before, nor a cause, because time itself, which the idea of before and causation is predicated upon, began its existence synchronously with the Big Bang. I find this nearly impossible to grasp in a fundamental way, because our entire existence is based around and upon a notion of time as a strict linear progression of one thing to another, with every event having a causation and time preceding it.

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The Galaxy's Dark Secret

Let's talk a little bit about our galaxy. You probably know that it's a spiral galaxy, with several "arms" reaching out from a central bulge, and is shaped like a disk. Most of our galaxy's mass is centered in that central bulge, with is about 13,000 light-years from top to bottom (which is really, really big), and has a density of around 1,600 stars per cubic light-year. To put that in perspective, out where we are in the Milky Way it's only a few thousand light-years thick (which is still really big), and the stellar density is closer to 0.004 stars per cubic light-year.

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What's (the) Matter?

Matter. It's basically everything. Anything you can see and touch (except holograms), and some things that you can't see or touch, is matter. There's plain old boring matter, which is all the things you see around you all the time, and is composed of atoms you see on the periodic table. But then there's all that cool weird matter (not necessarily strange or exotic matter, because those are actual, real names of types of matter). Since you're already probably pretty familiar with prosaic matter, having been interacting with it all your life, let's talk about some of the more interesting matter.

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Black Body Radiation

Every object* that is above 0 Kelvin (read: everything in the universe) radiates somewhere on the electromagnetic spectrum. Stick with me, and I'll explain why. But first, every object* also absorbs light somewhere along the electromagnetic spectrum. For example, let's take glass. Now, in the visible spectrum (390<λ<700 nm), glass doesn't really absorb, reflect, or emit light (which is why it's transparent). This is due to a quantum mechanics phenomenon called "quantization." Essentially, electrons and the like can only exist in discrete levels of energy, and nowhere in between (like steps on a staircase—you can be on one step or another, but not between them (at least not without falling)). This is odd, and somewhat counter-intuitive because it doesn't appear to occur at the macroscopic level (our daily lives), but it's completely true (as far as we know). When an object absorbs light, it's because that specific wavelength of light is enough to jump an electron...

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