http://simonwillison.net/2010-01-11T09:17:49+00:00Simon Willison2010-01-11T09:17:49+00:002010-01-11T09:17:49+00:00https://simonwillison.net/2010/Jan/11/gps/#atom-tag

<p><strong><a href="http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html">GPS and Relativity</a></strong></p> 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! <p><small></small>Via <a href="http://www.somebits.com/weblog/aviation/gps-altitude.html">Nelson Minar</a></small></p> <p>Tags: <a href="https://simonwillison.net/tags/gps">gps</a>, <a href="https://simonwillison.net/tags/mathematics">mathematics</a>, <a href="https://simonwillison.net/tags/physics">physics</a>, <a href="https://simonwillison.net/tags/relativity">relativity</a>, <a href="https://simonwillison.net/tags/spacescience">spacescience</a></p>

2008-08-02T23:58:26+00:002008-08-02T23:58:26+00:00https://simonwillison.net/2008/Aug/2/youtube/#atom-tag

<p><strong><a href="http://www.youtube.com/watch?v=j50ZssEojtM">YouTube: Large Hadron Rap</a></strong></p> The first time I saw this I thought it was incredibly dorky. By the third watch I realised I was actually learning things. <p>Tags: <a href="https://simonwillison.net/tags/cern">cern</a>, <a href="https://simonwillison.net/tags/funny">funny</a>, <a href="https://simonwillison.net/tags/large-hadron-collider">large-hadron-collider</a>, <a href="https://simonwillison.net/tags/physics">physics</a>, <a href="https://simonwillison.net/tags/rap">rap</a></p>

2008-06-07T14:49:04+00:002008-06-07T14:49:04+00:00https://simonwillison.net/2008/Jun/7/lhcountdowncom/#atom-tag

<p><strong><a href="http://www.lhcountdown.com/">LHCountdown.com</a></strong></p> 30 days until they turn on the Large Hadron Collider at CERN. <p>Tags: <a href="https://simonwillison.net/tags/cern">cern</a>, <a href="https://simonwillison.net/tags/large-hadron-collider">large-hadron-collider</a>, <a href="https://simonwillison.net/tags/lhc">lhc</a>, <a href="https://simonwillison.net/tags/particlephysics">particlephysics</a>, <a href="https://simonwillison.net/tags/physics">physics</a></p>

2008-01-26T12:25:06+00:002008-01-26T12:25:06+00:00https://simonwillison.net/2008/Jan/26/blob/#atom-tag

<p><strong><a href="http://dev.opera.com/articles/view/blob-sallad-canvas-tag-and-javascrip/">Blob Sallad - canvas tag and JavaScript physics simulation experiment</a></strong></p> Björn Lindberg provides a detailed code walkthrough of his brilliant canvas demo, inspired by Loco Rocco. <p>Tags: <a href="https://simonwillison.net/tags/bjornlindberg">bjornlindberg</a>, <a href="https://simonwillison.net/tags/canvas">canvas</a>, <a href="https://simonwillison.net/tags/javascript">javascript</a>, <a href="https://simonwillison.net/tags/locorocco">locorocco</a>, <a href="https://simonwillison.net/tags/opera">opera</a>, <a href="https://simonwillison.net/tags/physics">physics</a>, <a href="https://simonwillison.net/tags/tutorial">tutorial</a></p>