look-back time
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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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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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What is a Light-Year?
In my article, “Where Are We?” I showed you just how huge astronomical distances really are. There’s a reason people say that incredible things are “astronomical!” The image above illustrates how far Earth is from several faraway objects, including one…
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What was the Big Bang?
Have you heard of the Big Bang? I still remember the first time I heard about it. I was little; I can’t remember if I’d fallen in love with astronomy yet. But I do remember sitting in my living room,…
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A Full Story of Galactic Evolution
Over the course of the last few posts, we’ve explored different types of active galactic nuclei: Seyfert galaxies, double-lobed radio sources, and quasars. At the heart of each of these galaxies lies a supermassive black hole, feeding off an energy…
