Bitcoin.
Running, uninterrupted, since January 3, 2009
No bank runs it, no country prints it, no company owns it. It exists because tens of thousands of computers run the same rules — and the rules don’t change.
“A peer-to-peer electronic cash system.”
Proof of Work
Digital information can be copied infinitely. A photo, a document, a dollar. If it’s just data, nothing stops you from duplicating it. So how do you create digital money that can’t be doubled? You need proof that real work was done to create it.
Think of a combination lock with a billion possible combinations. Finding the right one takes real time and real effort. You can’t fake it. You can’t shortcut it. But once someone finds it, anyone can verify it’s correct in seconds. Proof of work is that lock, applied to math.
What does the winner actually write? A new page of Bitcoin’s ledger. A public log of every transaction ever made, copied across tens of thousands of computers around the world. Nobody owns it. Anyone can read it. Change one entry on one copy and the rest of the network rejects yours.
The protocol picks the page-writer through a lottery you can’t game with cleverness. You buy your ticket with electricity.
The hash race.
Every block is a brute-force lottery. Millions of machines hammer a number into SHA-256, hunting for a hash that starts with nineteen zeros. Whoever finds one first writes the next block.
~ 6 × 10²⁰ guesses per block
one winner every ~10 minutes
A hash is one guess at the puzzle. Every miner is taking the next block, adding a random number, hashing the whole thing through SHA-256, and checking if the result wins. Hashrate is how many of those guesses the network can make per second.
Network hashrate · May 2026
exahashes per second · ~1 quintillion guesses, globally
If every laptop on Earth was guessing full-tilt, you’d still need to multiply by ~500,000 to match it.
source · Cambridge CBECI
That number is the security. The bigger it gets, the more expensive it becomes for anyone to outcompete the chain. To forge a transaction, you’d need to outguess the entire global network, and keep outguessing it for as long as the lie needed to stand.
Mathematically possible. Economically irrational.
The puzzle auto-adjusts every two weeks. More miners competing means harder puzzles. Fewer miners means easier ones. Either way, a new block lands roughly every ten minutes, regardless of how much computing power is pointed at the network.
Like clockwork. For sixteen years.
04 · Store of Value
Why is it worth something?
Three legs of a stool. Take any one away, the value collapses.
Scarcity
Only 21 million will ever exist.
The schedule was hard-coded in 2009 and has never moved.
Math
The cryptography is provably unbreakable with current technology.
SHA-256 has 2²⁵⁶ possible outputs — more than atoms in the universe.
Agreement
Millions of people choose to trade for it. Every day.
Nobody can force you to accept bitcoin. Nobody can stop you, either.
Three legs hold. So does the value.
The first time anyone agreed
On May 22, 2010, Laszlo Hanyecz paid 10,000 BTC for two Papa John’s pizzas.
At today’s price, those pizzas would cost
$0He says he doesn’t regret it.
He wrote the paper. Mined the first block. Then disappeared.
Open the fileCommon questions
Practical stuff.
On this day
Today in Bitcoin.
Today
Bitcoin keeps producing blocks
No special anniversary today. The network has produced a block every ten minutes since January 3, 2009 — uninterrupted.