Bitcoin's mining network has grown so powerful that a computer that once guided astronauts to the moon would now need 13 million times the age of the universe to find a single block. This striking comparison comes from a 2019 experiment by computer scientist Ken Shirriff, whose work is circulating again this week and offers a vivid lesson in how dramatically the Bitcoin network has evolved.

What Happened When the Apollo Computer Tried to Mine Bitcoin?

In 2019, Shirriff programmed an Apollo Guidance Computer (AGC), the legendary machine that navigated the Apollo moon missions, to perform Bitcoin mining calculations. The AGC, which weighs about 70 pounds and contains roughly 4 kilobytes of RAM, managed to compute one Bitcoin hash every 10.3 seconds. To put that in perspective, Bitcoin mining requires solving cryptographic puzzles using a function called SHA-256, and the AGC needed 5.15 seconds just to compute a single hash.

The experiment was purely educational. Shirriff fed the AGC a block that had already been mined and confirmed it could reproduce the correct result, but the machine never earned a single satoshi, Bitcoin's smallest unit. The real value of the exercise was demonstrating just how far computing power has come since the 1960s and how that gap explains Bitcoin's security model.

How Much Has Bitcoin's Mining Power Grown Since 2019?

The numbers tell a dramatic story. In 2019, when Shirriff conducted his experiment, Bitcoin's network was running at approximately 65 exahashes per second (EH/s). That means the network was performing 65 quintillion hashes every second. At that difficulty level, Shirriff calculated the AGC would need about 4 times 10 to the 23rd power seconds to find a block, or roughly one million times the age of the universe.

Fast forward to September 2026, and Bitcoin's hashrate has reached 934 EH/s following a difficulty adjustment on September 5. That represents roughly 14 times the hashrate Shirriff faced in 2019. Scaling his original estimate by that factor, the AGC would now need approximately 5.8 times 10 to the 24th power seconds to mine a block, or about 13 million times the age of the universe.

Why Does This Matter for Understanding Bitcoin Mining?

The Apollo computer comparison illustrates a fundamental principle of Bitcoin's design: proof-of-work security. Bitcoin's mining system requires miners to solve computationally difficult puzzles to validate transactions and earn rewards. The more computing power dedicated to mining, the harder those puzzles become, and the more secure the network becomes. The exponential growth from 65 EH/s to 934 EH/s demonstrates that security has increased dramatically.

This growth also reflects the industry's evolution. Shirriff's collection includes other historical computers he has tested for mining capability. An IBM 1401 mainframe from the early 1960s needed 80 seconds per hash, while a 1973 Xerox Alto managed 1.5 hashes per second. Each represents a snapshot of computing capability at its time, but none could compete with modern application-specific integrated circuits (ASICs) designed specifically for Bitcoin mining.

What's Happening With Bitcoin Mining Economics Right Now?

While the hashrate has grown substantially, the mining industry is navigating a complex economic landscape. Bitcoin's difficulty increased 1.31% at block height 965,664 in early September, marking the eighth difficulty adjustment of 2026. This means mining became slightly harder, but the network's hashrate has remained relatively flat at 934 EH/s, staying below the 1 zettahash per second (ZH/s) threshold.

The stalled hashrate growth is notable because it suggests miners are being cautious about expansion. Despite a 22.24% jump in hashprice, the metric that measures mining revenue per unit of computing power, from $32.42 to $39.63 per petahash per second per day, miners have not significantly increased their hardware deployment. This restraint may reflect hardware limitations or a wait-and-see approach as the industry evaluates profitability.

Miner revenue remains heavily dependent on Bitcoin's price rather than transaction fees. Over the last 24 hours tracked in early September, fees represented just 0.43% of total miner rewards, meaning the block subsidy, the newly created Bitcoin awarded to miners, is the primary income source. Bitcoin's price reached $81,000 in mid-September, providing a welcome boost for an industry whose difficulty sits 13% below where it started the year.

How to Understand Bitcoin's Difficulty Adjustment System

• Adjustment Frequency: Bitcoin's protocol automatically recalibrates mining difficulty every 2,016 mined blocks, roughly every two weeks, to keep block times steady at approximately ten minutes per block.
• Hashrate Relationship: When hashrate increases and blocks are mined too quickly, difficulty rises to compensate; when hashrate decreases and blocks come in too slowly, difficulty drops to encourage participation.
• 2026 Volatility: This year has seen 18 distinct difficulty changes, with ten decreases totaling 45.27% offset by eight increases totaling 33.34%, resulting in a net 11.93% decline from January through September.

The difficulty system is Bitcoin's self-regulating mechanism. It ensures that regardless of how much computing power joins or leaves the network, blocks continue to arrive at a predictable rate. This predictability is essential for Bitcoin's function as a currency and store of value.

The Apollo Guidance Computer experiment, while a historical curiosity, ultimately demonstrates why modern Bitcoin mining requires specialized hardware and massive energy investment. The gap between a 1960s-era computer and today's mining network is not just a matter of speed; it reflects the fundamental security model that makes Bitcoin's decentralized consensus possible. As the network continues to evolve, that gap will only grow wider.