The Milky Way Demystified

Alright, people…time to finish off our exploration of the Milky Way Galaxy, our home in the cosmos!

For the past nine weeks, we’ve covered everything from how our galaxy was “discovered” to how it may have formed. But there’s so much more to explore–and, starting next week, we’ll begin covering the vast universe of galaxies beyond our own!

But before we do that…I want to wrap up our discussion of our own galaxy with an overview to tie the last nine posts together.

(By the way, has anyone noticed I actually managed to chug out a post a week for the entire Milky Way “module”? I’m a bit impressed with myself for that!)

Anyway…on to the Milky Way!

Continue reading

Stellar Evolution Demystified

Whaddya know…after what seems like a geological age, we’re finally done with stellar evolution! And we’ve covered a truly ridiculous amount of information.

We’ve covered a star’s relatively gentle, humble beginnings within the collapsing cores of giant molecular clouds (or GMCs). We’ve explored how stars begin fusing hydrogen nuclei for fuel and how their interiors work.

We’ve covered how they evolve across the main sequence, and how they eventually exhaust their fuel, lose stability, and expand into giants.

We’ve delved into the way low- and medium-mass stars quietly expel their atmospheres and shrink into inert balls of carbon called white dwarfs. And we’ve watched as massive stars burst apart in brilliant supernova explosions and then collapse into some of the most extreme objects in the universe, neutron stars and black holes.

Those three end states–white dwarfs, neutron stars, and black holes–are known as compact objects, and we’ve explored them too.

If it all seems super complicated…I understand. But now, just as I did once with types of stars, I’m going to give you an overview to put it all together.

Continue reading

Star Types Demystified


By now, I’ve introduced you to a lot of different ways to classify stars.

Months ago, I talked about the different spectral classes—O, B, A, F, G, K, and M. Even before that, I told you about apparent visual magnitude, our ranking system for how bright stars appear to the naked eye.

More recently, we explored absolute visual magnitude and the related absolute bolometric magnitude and luminosity. All these are related to a star’s actual brightness, not just how bright they seem to be from Earth.

And last but not least, we talked about the H-R diagram and how to rank stars by their luminosity classification.

In short, it may seem like sorting stars is a complicated business. But it’s not really. And here, I intend to give you an overview to put all this together.

Continue reading