Astronomy
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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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Could the Universe be Curved?
I know…that seems like a strange question to ask, doesn’t it? Out of context, it makes no sense at all. What are we even talking about? The curvature of what? Cosmology is full of questions like this — questions that…
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The Shape of Space
I’ll admit it: when I hear something like “the shape of space,” my first thought is, whaaaaa? It’s hard to talk about the science behind space itself because we first have to wrap our minds around what that even means.…
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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…
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From the First Nuclei to First Light
When we talk about the first 30 minutes of time, we describe the universe expanding and cooling. As the universe cooled, the nuclear reactions that produced the first atomic nuclei slowed and stopped. But it was only relatively cool. The…
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The First Nucleosynthesis
One minute after the Big Bang, all the protons, neutrons, and electrons that would ever exist had been produced. There were no atomic nuclei, though. No atoms. No materials as you and I know it — like wood, metal, or…
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Astronomical Measurements
I’m sure many of you know of Han Solo’s famous Kessel Run — which he made in “less than 12 parsecs.” He says this as if he’s declaring a new time record, like I might brag that I ran a…
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The Universe’s First Moments
Imagine a time before galaxies existed, before the first stars had been born, before the most basic building blocks of matter — atoms — had formed. This was mere moments after the Big Bang. No one understands how matter and…
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The Cosmic Microwave Background Radiation
What if I told you that this was an actual image of the night sky? Well…alright, I admit it’s more like a map. Specifically, a map of the cosmic microwave background radiation, often known simply as the CMB. This is…
