giant molecular clouds
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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…
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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…
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Unique Neutron Stars
Neutron stars — the compact remains of massive stars that have gone supernova — are some of the most extreme objects in the universe, narrowly beaten by black holes (and, as we’ll talk about in future posts, active galaxies and…
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What are Planetary Nebulae?
Meet the planetary nebula, one of the universe’s most gorgeous phenomena. If you’ve ever looked through a telescope, you may have seen one of these before. Through a small telescope, one might look like a little planet — hence the…
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Story of a Star Cluster
Meet M13, one of my favorite globular star clusters. M13, also known as Messier 13 or the Hercules Cluster, is found — surprise surprise — in the constellation Hercules in the northern hemisphere. The really cool thing about star clusters…
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Stars: The Limits of “Normal”
How big — or small — can a star get? As with most questions in astronomy, the answer to that is not definitive. But stellar models can give us a pretty good idea. Mathematical models of stars tell us that…
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What is Contagious Star Formation?
Recognize this nebula? Yeah…we’re talking about the Orion Nebula again. I know, we already took a tour through the Orion constellation in my last post…but there’s still more to cover about how stars come to life, and Orion is still the…

