gravitational lensing
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Globular Clusters: The Untold Story
Meet Messier 13: my sentimental favorite globular cluster. For more than a decade now, one of my favorite things has been to set up my telescopes at astronomy outreach events and show people the night sky. I have two telescopes…
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Dark Matter: How Do We Know?
In theoretical physics, there are countless theories as to what dark matter is. But how do we know it’s not a wild goose chase? Technically speaking, we don’t. But fortunately for us, this question comes back to one of the…
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Dark Matter: What We Know
I considered titling this post “Dark Matter Demystified” and including it in my “Cosmos Demystified” series…but honestly, there are some promises I can’t make! Dark matter is one of the most mysterious concepts in cosmology, second only to the even…
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The Problem of Matter
At first glance, this is an ordinary image of a galaxy cluster: specifically, Abell 1689. If we look closer, though, we see that there’s something weird going on with the more distant, background galaxies in the image. Many of those…
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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…
