Cosmic Microwave Background

An irreverent and humorous explanation of the Cosmic Microwave Background radiation. Discover how the Big Bang's afterglow, a universal static humming at 2.725 Kelvin, was discovered and what it tells us about our universe's pimply adolescence.

7/24/2025

Calcutta—is a city where entropy doesn’t just increase—it metastasizes. Walk down rashbehari avenue in the july heat and you will not only discover spontaneous human combustion, but also the truth that the big bang wasn’t an event 13.8 billion years ago, but rather, something ongoing: a continuous, ceaselessly tooting cosmic poot whose faint echo is what astrophysicists pompously call the cosmic microwave background radiation. Fancy words for something that’s essentially the universe’s weak residual flatulence from when it was a teenager.

But what exactly is this “cosmic microwave background”? Why “microwave”? Is it reheating last night’s biryani at 2 AM, hating itself? No—although that’s cosmically close. It’s the leftover radiation, the faint afterglow of the early universe when everything was hotter than a College Street tram stuck in traffic in July. Etymologically, “microwave” comes from the Greek “mikros” meaning “small” and Latin “vibrare” meaning “to shake,” so essentially, it’s just very small, shaky waves of ancient universal belches, echoing endlessly, utterly bored by their own immortality.

Let’s consider this backdrop from calcutta’s unique and as always unsterile and stale standpoint—as it bravely battles entropy with sheer inertia of torpidity. While the rest of the world moved ahead, probing the deep universe with COBE, WMAP, Planck, and other shiny toys named after dead people who didn’t live long enough to see how their names got mangled in YouTube explainers, Calcutta remained stoic, unbothered by the universe’s baby pictures plastered everywhere. Out here, “inflation” isn’t the rapid exponential expansion of space-time; it’s simply vegetable prices soaring during Durga Puja—same difference, different priests.

Anyway I forget why I started this blog sometimes, remind me to rewind always, old men like me like to do this, so rewind to 1964, when two astronomers, Arno Penzias and Robert Wilson—armed with an antenna as sensitive as a bengali poet post-breakup picked up, and accidentally at that, static they couldn’t explain. After scratching their, well, you-know-what, and checking for pigeon dung (which, incidentally, was found and carefully scrubbed off the antenna), they realized they had stumbled upon the universe’s leftover background hum. Nobel prizes ensued, proving once again that the universe rewards confusion with fame, fortune, and endless committees.

Now, as for the cosmic microwave background itself, here’s what you really need to know: the radiation hums at about 2.725 Kelvin (–270.425 Celsius), only slightly colder than an Indian kakistocrat’s sphincter (that’s where their brain is) but slightly warmer than the tea you always forget to drink.

Everywhere you point your telescope—north, south, Howrah Bridgewards, into your neighbor’s rear hole—you’ll detect this same microwave fuzz. Why? Because the universe began hotter than Mamata Banerjee during a press conference, then cooled like roadside chai in monsoon rains, leaving us with a universal static equivalent of that annoying parar dada who never stops playing Rabindra Sangeet through cheap blown-out desi speakers. And it’s everywhere—inescapably, relentlessly everywhere.

Mathematically, this is expressed by Planck’s blackbody formula (a piece of genius from Max Planck, a man who proved that energy, like patience for relatives at bengali funerals—mine is soon, comes in discrete, finite chunks):

This formula explains why your night sky isn’t blazing with light; why, instead, it’s a dim, boring glow from long before imagined gods, humans, and post-colonial plumbing made urinals in Calcutta worse. And yet, paradoxically, that dim glow is the oldest portrait we have of our only fractured reality—a universal selfie before all self-indulgent selfies, cosmic lingam-pics broadcast eternally through the ether.

In short, the cosmic microwave background is a universal embarrassment, a ghostly echo of the universe’s adolescence, when everything was acne-riddled, overheated, and desperately expanding. It’s an eternal reminder, bouncing around calcutta’s electromagnetic gutters, that we’re all riding the same cosmic tart poot toward eventual oblivion—where even entropy itself will grow tired and bored, and existence will yawn into nothingness.

Now—if you find all this science mumbo-jumbo exhausting, go warm some leftover mutton rezala in your kitchen microwave and remind yourself: you’re literally cooking dinner using the same electromagnetic waves that whisper the secrets of the universe’s pimply, embarrassing adolescence. How’s that for existential dread?