Emerging Technologies › AI and Data · Feature · Practical STEM, Part 10
How information travels: Claude Shannon and the bit
In 1948, Claude Shannon showed how to measure information and how to send it reliably through noise. His paper underpins the internet, mobile networks, compression and the deep-space links that bring us pictures from other planets.
Every time a video keeps playing on a shaky connection, you are watching a promise kept — a promise Claude Shannon proved could be kept.
Measuring information
Shannon worked at Bell Labs in the United States. In 1948 he published “A Mathematical Theory of Communication”. In it, he made a simple, radical move: he separated information from meaning. A message is a choice among possibilities. The more possibilities, the more information. The basic unit is the bit — one choice between two options.
Beating noise
Every channel has noise: static on a radio, scratches on a disc, interference in a cable. Before Shannon, engineers assumed cleaner messages needed more power or slower sending. Shannon proved something surprising: every channel has a maximum rate, its capacity. Below that rate, you can send information with almost no errors — if you encode it cleverly.
That result started a decades-long hunt for clever codes. Today’s best come remarkably close to Shannon’s limit, and mobile networks such as 5G rely on them.
Squeezing information
Shannon also showed that most messages contain repetition, and that repetition can be removed. This is compression. ZIP files, streaming video and music formats all build on the idea that you only need to send what is surprising.
Where it runs today
- The internet and Wi-Fi, where error-correcting codes repair damaged data automatically.
- Mobile networks, which squeeze ever more data through the same airwaves.
- Space missions, where faint signals from billions of kilometres away are decoded without errors.
- AI, where ideas from information theory help measure how well a model predicts.
The practical lesson
Define what matters, then measure it. By setting meaning aside and counting choices, Shannon turned communication into engineering. He was also famously playful — he built juggling machines and rode a unicycle through Bell Labs’ corridors. Serious work and play are not opposites. Often, one fuels the other.
Try it yourself
Think of a number between 1 and 100. How many yes-or-no questions does a friend need to guess it, at most? (Answer: 7, because 2⁷ = 128.) That number of questions is the information in your choice, measured in bits.
Sources: Shannon, “A Mathematical Theory of Communication,” Bell System Technical Journal 27 (1948) · Soni and Goodman, A Mind at Play (2017) · Richardson and Urbanke, Modern Coding Theory (2008) · 3GPP TS 38.212, 5G NR channel coding.
How this story was made: drafted by Luise Hönig (Virtual Contributor), completed by Viktoria Kaiser, approved by Yoshihiro Horiuchi, Editor-in-Chief.
How this story was made: drafted by Luise Hönig (Virtual Contributor), completed by Viktoria Kaiser, approved by Yoshihiro Horiuchi, Editor-in-Chief.