Sync: 8 key ideas
The core ideas of Sync, each in under a minute, written in our own words. Want the full depth? Get the book.
- IDEA 1 OF 8
Nature loves to synchronise
Strogatz shows that synchrony appears everywhere, from fireflies to heart cells to planets.
Many separate rhythms can fall into step without any leader telling them what to do, which he finds one of nature's deepest puzzles.
- IDEA 2 OF 8
Fireflies flash in unison
Strogatz describes trees in Southeast Asia where thousands of fireflies flash together.
Each insect adjusts slightly to its neighbours' flashes, and through these small nudges the whole tree gradually begins to blink as one.
- IDEA 3 OF 8
Oscillators pull each other into step
Strogatz explains coupled oscillators, things that repeat a cycle and influence one another.
Models by Arthur Winfree and Yoshiki Kuramoto showed that once coupling is strong enough, a group suddenly locks into a common rhythm.
- IDEA 4 OF 8
Our bodies keep time
Strogatz describes circadian rhythms, the daily cycles of sleep, temperature and hormones in the body.
Experiments in caves without clocks showed these rhythms drifting apart, revealing that the body contains several internal clocks.
- IDEA 5 OF 8
A bridge wobbled from walkers
Strogatz describes London's Millennium Bridge, which swayed when it opened because pedestrians unconsciously matched their steps to its motion.
The crowd and the bridge synchronised, making the wobble worse until engineers added dampers.
- IDEA 6 OF 8
Physics uses synchrony too
Strogatz explains that lasers work because countless atoms emit light in step.
He also describes superconducting devices whose quantum behaviour depends on synchrony, showing the idea's reach from biology to technology.
- IDEA 7 OF 8
Networks can be small worlds
Strogatz describes his work with Duncan Watts on small-world networks, in which a few long-range links connect distant clusters.
Such networks help explain why ideas, diseases and rhythms can spread so quickly.
- IDEA 8 OF 8
Synchrony can help or harm
Strogatz notes that synchrony can be useful, as in a steady heartbeat, but also dangerous, as in epileptic seizures or power grid failures.
Understanding it helps scientists predict and control these collective behaviours.
Get one idea like this every daySwipe through ideas, go deeper on any of them, and save the ones that matter. Free.
Read Sync in the app