-
Archives
- April 2026
- March 2026
- February 2026
- January 2026
- December 2025
- April 2025
- January 2025
- November 2024
- September 2024
- March 2024
- January 2024
- November 2023
- October 2023
- September 2023
- June 2023
- April 2023
- March 2023
- February 2023
- December 2022
- October 2022
- September 2022
- July 2022
- June 2022
- May 2022
- December 2021
- November 2021
- October 2021
- September 2021
- August 2021
- July 2021
- April 2021
- March 2021
- January 2021
- December 2020
- October 2020
- August 2020
- April 2020
- March 2020
- February 2020
- November 2019
- July 2019
- June 2019
- April 2019
- March 2019
- February 2019
- January 2019
- December 2018
- October 2018
- April 2018
- February 2018
- November 2017
- September 2017
- July 2017
- June 2017
- May 2017
- April 2017
- March 2017
- February 2017
- January 2017
- December 2016
- November 2016
- August 2016
- July 2016
- June 2016
- May 2016
- March 2016
- February 2016
- January 2016
- December 2015
- November 2015
- October 2015
- September 2015
- August 2015
- June 2015
- May 2015
- April 2015
- March 2015
- January 2015
- December 2014
- November 2014
- October 2014
- September 2014
- August 2014
- July 2014
- June 2014
- May 2014
- April 2014
- March 2014
- February 2014
- January 2014
- December 2013
- November 2013
- October 2013
- September 2013
- August 2013
- July 2013
- June 2013
- May 2013
- March 2013
- February 2013
- January 2013
- December 2012
- November 2012
- October 2012
- August 2012
- July 2012
- June 2012
- May 2012
- April 2012
- March 2012
- February 2012
- January 2012
- December 2011
- November 2011
- October 2011
- August 2011
- July 2011
- June 2011
- May 2011
- April 2011
- March 2011
- February 2011
- January 2011
- December 2010
- November 2010
- October 2010
- September 2010
- August 2010
- July 2010
- June 2010
- May 2010
- April 2010
- March 2010
- February 2010
- January 2010
- December 2009
- November 2009
- October 2009
- September 2009
- August 2009
- July 2009
- June 2009
- May 2009
- April 2009
- March 2009
- February 2009
- January 2009
- December 2008
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- September 2007
- August 2007
- July 2007
- June 2007
- May 2007
- April 2007
- March 2007
- February 2007
- January 2007
- December 2006
- November 2006
- October 2006
- September 2006
- August 2006
- July 2006
- June 2006
- May 2006
- April 2006
- March 2006
- February 2006
- January 2006
- December 2005
- November 2005
- October 2005
- September 2005
- August 2005
- July 2005
- June 2005
- May 2005
- April 2005
- March 2005
- February 2005
- January 2005
- December 2004
- November 2004
- October 2004
- September 2004
- August 2004
- July 2004
- June 2004
- May 2004
- April 2004
- March 2004
- February 2004
- January 2004
- December 2003
- November 2003
- October 2003
- September 2003
- August 2003
- July 2003
- June 2003
- May 2003
- April 2003
- March 2003
- February 2003
- January 2003
- December 2002
- November 2002
- October 2002
- September 2002
- August 2002
- July 2002
- June 2002
- May 2002
- April 2002
- March 2002
- February 2002
-
Meta
Category Archives: sciences
the Big Whack
Giant impact hypothesis It has been said (though not in that article) that the Pacific Ocean is the scar of the whack. So if the whack hadn’t happened, would Earth’s crust be all continental? In that case the plates would … Continue reading
Posted in sciences
2 Comments
the greatest thing ever!
Forgive my waxing hyperbolic . . . This is a tiling of the hyperbolic plane by triangles whose angles are π/2, π/3, π/7 – the smallest possible tile. I present it in a conformal mapping analogous to the Mercator projection, which I’ve … Continue reading
Posted in eye-candy, mathematics
1 Comment
looking for sanity checks in an insane world
Some years ago, using basic theorems of hyperbolic trigonometry, I worked out a conformal representation of the hyperbolic plane which preserves one line – analogous to the Mercator projection of the sphere, a conformal map which preserves one great circle. … Continue reading
Posted in mathematics
1 Comment
what the cat did in the night-time
Whenever I get settled in my big chair, Pillow (the junior cat) is all over me; but when I’m in bed he almost never comes within reach. So I was surprised when, on waking in the night, I found him … Continue reading
Posted in medicine, pets
3 Comments
to balance a calendar
A Martian year is 668.6 Martian days; that’s 3.4 less than 24×28. I asked myself, how should the short months be arranged for best ‘balance’? I ran all combinations and this is it: The three big dots represent the missing … Continue reading
symmetries made simple
This may be of interest to only a few: Simplest Canonical Polyhedra of Each Symmetry Type (rotable in Java); in other words, canonical forms of the simplest topologies that allow the specified symmetries and none higher. Any convex polyhedron can … Continue reading
Posted in mathematics
Leave a comment
how much is in there?
I reloaded MacOS, restored my home directory from backup, and was surprised to learn that I have 3e5 files. Most of the bulk is music, but that’s only 7e3 files. Is there a tool analogous to du that gives the … Continue reading