GPS: a timing race between your phone and four satellites
Your phone never talks to a GPS satellite. It times radio signals from four of them, and the FAA says that fixes you to within about 7 metres.
tag archive
#physics.
Every story tagged #physics.
The trouble with ice on a wing
Even thin frost on a wing cuts lift and adds weight. Crews melt it with heated orange glycol, then add a thicker green fluid to stop new ice forming.
A small error today can spoil next week's forecast
A small starting error grows daily inside the atmosphere's chaos, limiting how far a forecast can see. A warmer ocean can ease that limit, research shows.
The sky is blue because air scatters blue light, not the sea
Air molecules scatter blue light far more than red. That's why the sky is blue, not because it reflects the sea, and why sunsets turn red.
The geometry lecture that waited 61 years for Einstein
Bernhard Riemann's 1854 lecture on curved space sat mostly ignored for decades before Albert Einstein built general relativity on its ideas in 1915.
A heat pump moves heat, which is why it works far below freezing
A heat pump carries heat from outdoor air into a home rather than burning fuel. That lets it run far below freezing, and run backwards to cool a room.
Carbon dating can age remains up to about 60,000 years old
Carbon dating measures decaying carbon-14 against stable carbon-12 to work out how long ago an organism died, a method Willard Libby built in Chicago.
Delays sent the first nuclear reactor to a Chicago squash court
Arthur Compton moved the reactor under Stagg Field in 1942 after the planned site stalled. Enrico Fermi's team then ran the first chain reaction.
A comet's tail points away from the sun, whichever way it flies
Sunlight and the solar wind, not a comet's own motion, decide which way its tail streams as the comet swings past the sun.