20120108, 19:35  #1 
"Daniel Jackson"
May 2011
14285714285714285714
1010000011_{2} Posts 
Number of miles in a light year is prime!
Did you know that the number of miles in a lightyear, rounded to the nearest integer, is prime? Here's the number:
5874601673407 The real value is 5874601673407+2/(11*127) miles. Google doesn't show any results for "5874601673407 prime number", so I guess no one knew. 
20120108, 19:45  #2  
Feb 2004
2^{5}·5 Posts 
Quote:


20120108, 19:56  #3 
"Daniel Jackson"
May 2011
14285714285714285714
643 Posts 
It's the definition for a nonleapyear. In other words, it worked for 2009, 2010, and 2011, and it will also work for 2013, 2014, 2015, and every year that isn't of the form 4*x

20120108, 20:14  #4 
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
10AB_{16} Posts 
According to Wikipedia, a light year is actually defined as the distance light travels in one Julian year, i.e. 365.25 days precisely, (regardless of leap years and leap seconds) which is about 5,878,625,373,183.608 miles. 5878625373184 = 2^{10} * 5107 * 1124113. You've given the distance for 365 light days. While still an interesting bit of trivia, that likely explains the lack of others noting it previously (at least, as far as you could find).
Last fiddled with by MiniGeek on 20120108 at 20:19 
20120108, 20:40  #5  
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
1C35_{16} Posts 
Quote:


20120108, 21:46  #6 
I quite division it
"Chris"
Feb 2005
England
31×67 Posts 
This thread could be why we don't attract women.

20120109, 01:04  #7 
Einyen
Dec 2003
Denmark
BDC_{16} Posts 
I'm not sure what is the official definition of a lightyear, there are many different values:
Wikipedia: 5,878,625,373,183.608 miles (9,460,730,472,580.8 km) Online Conversion: http://www.onlineconversion.com/length_all.htm Light year (Julian): 5,878,625,373,200 miles (9,460,730,472,600 km) Light year (Tropical): 5,878,499,814,100 miles (9,460,528,404,900 km) Light year (traditional): 5,874,601,673,400 miles (9,454,254,955,500 km) My old Texas TI85 calculator conversion: 5,878,499,814,135.1 miles (9,460,528,404,879.4 km) 
20120109, 01:44  #8  
"Forget I exist"
Jul 2009
Dumbassville
8384_{10} Posts 
Quote:


20120109, 02:01  #9 
Romulan Interpreter
Jun 2011
Thailand
2438_{16} Posts 

20120109, 02:13  #10  
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
3×29×83 Posts 
Quote:
Quote:
Last fiddled with by Dubslow on 20120109 at 02:14 

20120109, 02:17  #11 
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
4267_{10} Posts 
Wikipedia's source is http://www.iau.org/public/measuring/, which looks official enough to me! Besides defining the "year" as 365.25 days, it gives the distance in KM, which converts to the number I gave.
Of course, nonstandard usages can be used anyway (and are, given your links; which also show a level of precision too low to give the precise integer), but regardless, an official standard definition exists. 
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