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Month: January 2009

My Eddington Number is 48

My Eddington Number is 48

A couple days ago I was browsing the internet on astrophysical topics, when I came across Sir Arthur Stanley Eddington’s wikipedia page. He’s best known for the Eddington limit, which describes the luminosity limit of a star as a function of its mass. Near the bottom of his page linked above, there is a description of the “Eddington number,” which for any person is the greatest number of bike rides they done which have been that at least that number in miles long. From the wikipedia page:

The Eddington Number in this context is defined as E, the number of days a cyclist has cycled more than E miles. For example an Eddington Number of 70 would imply that a cyclist has cycled more than 70 miles in a day on 70 occasions.

This is very similar to the Erdös number and the h-index, which measure a scientists publishing impact. I don’t have an Erdös number, nor an h-index, but I do have an Eddington number. And since I have a nice GPS database of my rides, I figured I could easily calculate it.



Above shows two Eddington calculations, in miles and in kilometers. The curved blue line is x=y, and it’s curved because the y axis is using a logscale. Where the blue line intersects the Eddington lines is my Eddington number. The downward arrows show my actual integer Eddington numbers (48 for miles, 74 for kilometers), while the upward arrows show that 49 and 75 aren’t above the blue line, and thus aren’t my Eddington numbers. Since the definition is in miles, my true number is 48, but the kilometer calculation shows that the number is also a function of your unit.

Unfortunately, I don’t have records before I got my GPS, so my true Eddington number is surely larger.

Bookmarks for January 21st through January 24th

Bookmarks for January 21st through January 24th

These are my links for January 21st through January 24th:

Bookmarks for January 8th through January 16th

Bookmarks for January 8th through January 16th

These are my links for January 8th through January 16th:

Bookmarks for December 23rd through January 5th

Bookmarks for December 23rd through January 5th

These are my links for December 23rd through January 5th:

No More Tunnels

No More Tunnels

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By far my favorite place to ride my mountain bike (that is reachable without driving) are the single track ‘tunnels’ that are typically reached through Peñasquitos Park (although they aren’t actually inside the park, they are on non-park city land). They are called ‘the tunnels’ because for most of their length they are covered by low bushes and trees just over head height. There are four of them that total a few miles in length and vary in technical difficulty. Until about a month ago, they were somewhat illicit and not patrolled, now they are very expressly illegal. During the rainy season I think it’s perfectly reasonable to close them. Muddy and wet ground is especially susceptible to erosion, and nature doesn’t need human help to erode the ground during the rainy season. The ditch my bike is pictured in above was fairly level ground the last time I was there, less than a month ago (*).

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