The Marginalian
The Marginalian

The Surprising Science of Why It’s Dark at Night, Animated

The glowing edge of space, or how the expansion of the universe is affecting the visible spectrum.

We’ve already seen how humankind conquered the night, but why is the sky dark after nightfall in the first place? The real reason, like most of science, is far less obvious than it seems, and far more expansive. Count on the fine folks of MinutePhysics — who have previously explained why the color pink doesn’t exist and why the past is different from the future — and their signature hand-drawn animation to illuminate the answer. And if Richard Feynman didn’t give you enough pause in demonstrating that the fire in your fireplace is actually the light and heat of the sun, how about knowing that the glow of the sky you see today isn’t starlight but leftover light from the Big Bang? Now that’s a moment of cosmic awe.

All of our evidence seems to indicate that space has no edge, but the universe itself does — not a spatial edge, but a temporal one.

For a less scientific but no less delightful take on the subject, see Edward Gorey’s characteristically irreverent and altogether fantastic Why We Have Day and Night.

Published October 4, 2012




Filed Under

View Full Site

The Marginalian participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn commissions by linking to Amazon. In more human terms, this means that whenever you buy a book on Amazon from any link on here, I receive a small percentage of its price, which goes straight back into my own colossal biblioexpenses. Privacy policy. (TLDR: You're safe — there are no nefarious "third parties" lurking on my watch or shedding crumbs of the "cookies" the rest of the internet uses.)