galaxies
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Cosmology Demystified
That has got to be the single strangest post title I’ve ever written. Of all the whacky branches of science out there, cosmology almost takes the cake — second only, I think, to the downright trippy world of quantum mechanics.…
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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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The Universe: A Timeline of Discovery
Aaaaand she’s back! Sorry for the delay — school had me burnt out! Consider this: humanity has existed for just a few thousand years, and for most of that time, our existence has been constrained to one little blue mote…
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A Cosmological Timeline
We started covering cosmology way back in April. And since then, we’ve explored quite a bit — in fact, the grandest story the universe has to offer. We’ve followed the universe from the first fractions of a second after the…
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The Discovery of Dark Energy
In 1998, astronomers made an extraordinary discovery. Contrary to expectation, the expansion of the universe is accelerating. Astronomers wondered at first if their measurements were wrong; further measurements confirmed the results. And then confirmation of the expansion came in the…
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Should Expanding Space be Slowing Down?
Einstein’s theory of general relativity holds that matter curves the fabric of space-time. That’s how gravity works. In turn, that gravity shapes the fabric of the universe. Depending on how much mass is in the universe, gravitation can curve the…
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Why do Galaxies Exist?
When we look out into the sky, we see a universe filled with galaxies. Galaxies are the second-largest “structure” we’ve covered in depth on this blog. The largest so far have been galaxy clusters, which are just what the name…
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Cosmological Redshift Demystified
If you’ve been following my recent posts, cosmological redshift will likely be a familiar idea. I introduced it in my post on the Hubble Law. We revisited it again in our discussion of the size and brightness of galaxies. When…
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What is the Cosmological Principle?
What if I were to ask you: Are there any unique places in the universe? That is, does any one location in the universe have a special vantage point? Does the universe look different from different locations? You might say…
