galaxies
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Active Galaxies Demystified
Active galaxies are, without a doubt, absolutely spectacular. Though rare, they tell a critical part of the story of galaxies — and of the universe as a whole. And we’ve spent the last few posts exploring them in depth. But…
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A Full Story of Galactic Evolution
Over the course of the last few posts, we’ve explored different types of active galactic nuclei: Seyfert galaxies, double-lobed radio sources, and quasars. At the heart of each of these galaxies lies a supermassive black hole, feeding off an energy…
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How Supermassive Black Holes Work
We first took a peek at supermassive black holes back in our discussion of galaxies. But now that we’ve covered a few types of active galaxies, it’s time to take a deeper dive. Okay, I guess we won’t really be…
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Exploring Galaxy Clusters
What if we were to travel beyond our own Milky Way Galaxy, and foray out into the galactic wilderness of deep space? What do you think we’d expect to find? Would we find galaxies spread out apart from one another,…
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Is Dark Matter Real?
Here we are, people — it’s finally time to talk about dark matter! I’ve teased this subject in my last few posts. We’ve discussed how the idea originated — with observations of the rotation of galaxies. We’ve touched on the…
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A Peek at Supermassive Black Holes
There are few things in the universe quite as exciting as black holes. They’re in all the movies — I even wrote a post a few years ago on what the movies get wrong about them! Though some movies, like…
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How Massive are Galaxies?
If you needed to measure the mass of, say, a brick — or some other Earthly object — you could just set it on a scale. (Yes, scales measure mass, not weight.) With galaxies, it’s not so easy! I don’t…
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How Big and Bright are Galaxies?
The brightest galaxy in our night sky is the Andromeda Galaxy, our nearest intergalactic neighbor. Hey…notice we’re talking about intergalactic neighbors now? 😀 In most of the posts on this blog, we’ve talked about interstellar neighbors, interstellar space, etc. But…
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What is the Hubble Law?
Last week, I teased you with the idea that it’s actually easy to estimate distances to galaxies. I do mean estimate — and distance indicators are still important. The Hubble Law is named for Edwin Hubble, the astronomer who was…
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How Far Away are Galaxies?
Well, I’ll give you a spoiler: they’re ridiculously far away. Let’s consider for a moment what a light-year actually means. It sounds like a unit of time, but it’s actually the distance that light travels in one Earth year. Think…
