matter

From the First Nuclei to First Light

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When we talk about the first 30 minutes of time, we describe the universe expanding and cooling. As the universe cooled, the nuclear reactions that produced the first atomic nuclei slowed and stopped.

But it was only relatively cool.

The universe still held a temperature on the order of 1 billion kelvins–and that, by the way, converts to roughly 999,999,727°C, or 1,800,000,000ºF.

Ridiculous temperatures like those mean that the gases of the early universe must have been totally ionized. That is, electrons were not bound to atomic nuclei, and no atoms existed.

So how did we get to the universe we know today–a universe full of stars and galaxies?

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The Universe’s First Moments

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Imagine a time before galaxies existed, before the first stars had been born, before the most basic building blocks of matter–atoms–had formed.

This was mere moments after the Big Bang.

No one understands how matter and energy behave under the extreme conditions of the Big Bang itself. We can’t tell the story of the universe from exactly zero. But we can rewind the clock all the way back to the universe’s first one-millionth of a second.

So, what was the universe like back then?

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Star Mass and Density

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Bright-Stars-in-Space-4K-Wallpaper

What makes a star shine bright?

Much earlier on—probably months ago now—I explained how something called the proton-proton chain generates massive amounts of energy within stars, and enables them to fuel whole solar systems. That’s the battery of a star.

We’ll address the proton-proton chain later, when we start talking about star life cycles. We’ve still got some talk about nebulas and interstellar space to go before we get that far. For now, what’s important is that the proton-proton chain depends on high density.

That is, stars will have the strongest batteries if they have very dense interiors. It doesn’t really matter how dense their middles and atmospheres are. But conditions in their cores must be very dense.

You’ll find, if you study stars closely, that there is a definite relation between their densities, masses, and luminosities.

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The Proton-Proton Chain

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wind and water energy.jpg

Take a wild guess: how much energy do you think the sun generates?

Think about it. It definitely generates enough energy to power a world.

Humans depend on the photosynthesis of plants, which converts sunlight into energy. And that’s not all. Without energy from the sun, our atmosphere would behave very differently, and so would our oceans.

Everything that moves on Planet Earth does so because it has energy. And a lot of that energy comes from the sun. It doesn’t even stop there—obviously, the sun has plenty of energy to spare, if the recent influx of solar power means anything.

The sun is incredibly powerful. And it’s powerful enough to keep generating that kind of massive energy supply for billions of years.

So where does it get all its energy?

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The Building Blocks of the Universe

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atomic_line_spectra.png

“The Building Blocks of the Universe.” When you put it that way, atoms sound less like a topic specifically for a chemistry class and more like something astronomers might discuss.

They really are. I’ve got a fantastic reason to include atoms under astronomy, and its name is stellar spectra.

We’ve encountered stellar spectra before in these astronomy posts. When I wrote about the spectrograph, an instrument astronomers use to study data, I talked about spectral lines. I also promised we’d come back to elaborate on that later.

We’re not actually going to talk about the spectrograph in this post. I’m saving that for another time. For now, I’m going to cover atoms in a little more detail.

That way, we’ll have a better understanding of how they interact with light later on—and that will help us understand the spectrograph.

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Newton’s Laws of Motion

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Sir-Isaac-Newton-Jean-Leon-Huens.jpg

It’s said that Sir Isaac Newton was sitting under an apple tree when an apple fell on his head, and that’s when all his discoveries began.

Personally, I doubt that story—just as I doubt that Galileo Galilei ever dropped iron and wooden balls off the Leaning Tower of Pisa. His goal would have been to show that both objects hit the ground at the same time. Unfortunately, wind resistance would have gotten in the way.

Regardless of how Newton discovered gravity, his scientific achievements are monumental. In fact, we recognize him today as one of the greatest scientists to ever live, second only to the famous Albert Einstein.

Newton’s revelation that gravity draws objects toward Earth changed the course of modern science. But what exactly did he find out?

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What Matters?

/ Emma / 2 Comments

The simplest approach to chemistry is to start basic.

Not basic as in acids and bases, ha-ha…sorry, bad chemistry joke.

I mean basic as in, what the heck even is chemistry?

I admit that I’m better versed in astronomy than chemistry. I’ve studied chemistry for exactly one year of my life—last year, 12th grade. Astronomy, on the other hand, has been my strong suit and my passion for several years.

For me, these Wednesday posts are like a refresher course. I don’t actually remember everything I’ve learned. Good thing I bought a copy of the textbook.

So, I’ll start simple—because chemistry is the study of breaking complex things down to the simplest bits possible. It’s the opposite of astronomy. Astronomy studies huge, mind-blowing phenomena. Chemistry, on the other hand…is mind-blowingly small.

It’s the study of matter.

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