The Building Blocks of the Universe


“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. Continue reading

Elements and Compounds



Recognize this?

This is the periodic table, and it’s pretty much the most important table in all of chemistry.

All the little boxes on this “table” are elements, the simplest form of matter. You literally can’t break these down further. What’s the difference between an element and a substance, you ask?

Okay, well, think of it this way. In my post on matter and its forms, I used water as an example of a substance. Water has its own physical and chemical properties, it’s not a mixture of anything, and no matter how many times you divide it up, you’ll still have the same thing.

But water can be divided up into different things chemically. Continue reading