The Stuff of Nebulae


What you see here is the Trifid Nebula, a vast cloud of gas and dust in space.

In my last post, we explored why it looks the way it does. We discovered that the pink hues of emission nebulae are caused when extremely hot nearby stars “excite” the gas of the nebula itself to emit its own light, which our eyes perceive as pink.

The haze of blue to the right, on the other hand, is the result of light from hot young stars nearby getting scattered among the nebula’s dust particles. It looks blue for the same reason the sky looks blue. We call nebulae like this reflection nebulae.

And the black wisps of dark nebulae are hardly as ominous as they look; they’re simply ordinary clouds of gas and dust, ordinary nebulae, that we can only see because they’re silhouetted by brighter objects in the background.

But nebulae, for all their different names, are actually a heck of a lot more similar than you might think. Continue reading

Star Mass and Density


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. Continue reading

What Matters?


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. Continue reading