Astronomy
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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…
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The Different Shapes of Galaxies
By now, we’ve spent a heck of a lot of time exploring spiral galaxies. It makes sense — they’re certainly the most photogenic. Seriously. Do me a favor and do a quick Google search for galaxies. When I did, nearly…
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A Universe of Galaxies
When the earliest astronomers and philosophers looked up at the night sky, they never could have imagined a sight like this. What if I told you there are only four single stars in this image? That’s right. Four. The rest…
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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…
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How Did the Milky Way Form?
Over the course of my last eight posts, we’ve covered just about everything there is to cover about our home galaxy — or, well, at least the basics. We’ve explored how astronomers first discovered what that incredible, milky stream of…
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The Composition of the Milky Way
What is our home galaxy made up of? In the broadest sense, it’s made up of stars, clouds of dust and gas, and the mysterious dark matter. We could also get a little more detailed. We could say that it…
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Exploring the Milky Way’s Nucleus
Here is an edge-on illustration of our Milky Way Galaxy. (Keep in mind that the disk actually stretches quite a bit farther out from the budge than is apparent in this illustration. Proportionally, its full diameter makes its thickness less…
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What Are Spiral Arms?
Probably the most spectacular feature of our Milky Way galaxy is its spiral arms. We can’t get a probe far enough out yet to take a galactic selfie, but astronomers are reasonably sure that we live in a spiral galaxy.…
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Exploring the Milky Way’s Spiral Arms
The Milky Way — our home galaxy — is a spiral galaxy, a classification I often describe as pinwheel-shaped. The main difference between a spiral galaxy’s shape and a pinwheel’s shape is that spiral galaxies, like the Milky Way, only…
