radiation
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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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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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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 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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What Goes On Inside a Star?
Our sun is undoubtedly the star we know the best. It’s only 93 million miles away — which might seem far, but isn’t that large a distance when you realize that the nearest neighboring star is a whole 4.3 light-years…
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From Cold Cloud to Hot Protostar
Paradoxically, stars begin in the galaxy’s coolest places: the dense giant molecular clouds (or GMCs). This is not quite the paradox it seems, as in the beginning, stars require little else but gravity to form. And that’s really quite lucky, because…
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What is a Nebula Made of?
What you see here is the Trifid Nebula, a vast cloud of gas and dust in space. In my last post, we explored why it looks the way it does. We discovered that the pink hues of emission nebulae are caused…
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What Makes a Star Blue?
Albireo is the distinctive double star in the head of the constellation Cygnus. You can find it yourself if you look for the Summer Triangle amid the dusty trail of the Milky Way across the night sky. The brighter, orange…
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The Starlight We Can’t See
Find yourself a dark, unpolluted night sky on a clear night free of clouds, and you are very likely to look up into the heavens and see a sight quite like this. It’s what we see of the Milky Way,…
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The Solar Neutrino
Ever heard of a neutrino? Well, I guess now you have. But what exactly is a neutrino? Don’t worry, they’re not harmful. They’re passing through you this very second and you’ll never notice them, not in your whole life. They’ll never…
