Simon Willison’s Weblog

4 items tagged “physics”

GPS and Relativity (via) GPS satellite clock ticks need an accuracy of 20-30 nanoseconds. The satellites move fast enough that their clocks fall behind by 7 microseconds a day due to time dilation, but orbit high enough that the curvature of spacetime due to the Earth’s mass puts them forward by another 45 microseconds. GPS receivers have to perform relativistic calculations to determine their location! # 11th January 2010, 9:17 am

YouTube: Large Hadron Rap. The first time I saw this I thought it was incredibly dorky. By the third watch I realised I was actually learning things. # 2nd August 2008, 11:58 pm

LHCountdown.com. 30 days until they turn on the Large Hadron Collider at CERN. # 7th June 2008, 2:49 pm

Blob Sallad—canvas tag and JavaScript physics simulation experiment. Björn Lindberg provides a detailed code walkthrough of his brilliant canvas demo, inspired by Loco Rocco. # 26th January 2008, 12:25 pm