That’s great. I’ve gone through the whole lot. What strikes me is that there is a predictable pattern until around the 1980′s and they are at opposite ends of their orbits between 1950 and 1970 (150,000,000km Earth orbit plus 133,000,000km DA14 perihelion = 2.83 E11 metres).

After the 1980′s or so the close approaches flip to the other node (Feb). That is probably because the nodes are/were something like 179 days apart and not exactly half a year apart so instead of getting a close approach every 6 months, DA14 got reined in on the Feb node after the August node had had its turn. But that’s a guess and I realise you are doing whatever is the single closest approach- both nodes would have seen close approaches but August’s were the closest, then February.

I see what you say about starting the rock train at an inauspicious time. Are you going to rerun it, starting post 1913? As you say, it appears it had many years to build up a train. It may be better to go from 1919 but it would also be interesting to see what sort of ripples 1918 would make and then do another new experiment starting from 1919. But you’re the one who has to do it and I just sit back and watch! And I presume this list took some time- it’s clever to programme it for close approaches.

One last point: you had said that something seemed to be happening every 10 years. Was that what might be called a data mirage? A few comments back, it seemed you were concluding that the train was being broken up every ten years and so it wouldn’t have time to build up.

Andrew

‘Dominique Strauss-Kahn, another senior French politician’…there’s the problem, those last 3 words

What is the point given that as ever there is wall to wall idiocy?

Is there a real problem? Yes. Technically there are subtle issues.
It hits politics, money, double face.

So long as other providers of bad stuff are allowed to continue there is no chance the thin end of a wedge will be allowed insertion. Aircraft noise, railway noise, military noise, industrial noise.

Most of this stuff can be minimised or avoided but that doesn’t happen. This will not be accidental.

100 years of DA14 closest approaches to Earth ( in metres, times +/- 2.25 hours). My notion that there were regular close approaches seems to have been mistaken. After 1 Feb 1913, there was only one close approach: in Feb 1918. Snapshot shows Earth in green, Moon in blue, DA14 in red.

DA-14 closest approach: 6.9634449E10 on 07 Aug 1913 20:22:40 dt=8192.0 s
DA-14 closest approach: 4.0880796E10 on 16 Aug 1914 06:24:00 dt=8192.0 s
DA-14 closest approach: 1.20976261E10 on 22 Aug 1915 23:57:52 dt=8192.0 s
DA-14 closest approach: 1.59490068E10 on 20 Aug 1916 00:10:40 dt=8192.0 s
DA-14 closest approach: 2.9408684E10 on 07 Feb 1917 03:54:40 dt=8192.0 s
DA-14 closest approach: 4.35704E8 on 17 Feb 1918 05:07:12 dt=8192.0 s
DA-14 closest approach: 4.4532101E9 on 18 Feb 1919 12:58:40 dt=8192.0 s
DA-14 closest approach: 1.2513836E10 on 20 Feb 1920 19:35:28 dt=8192.0 s
DA-14 closest approach: 2.16767713E10 on 22 Feb 1921 17:06:08 dt=8192.0 s
DA-14 closest approach: 3.13907978E10 on 25 Feb 1922 15:38:40 dt=8192.0 s
DA-14 closest approach: 4.1436217E10 on 01 Mar 1923 01:33:52 dt=8192.0 s
DA-14 closest approach: 5.1702182E10 on 03 Mar 1924 06:56:00 dt=8192.0 s
DA-14 closest approach: 6.2074819E10 on 06 Mar 1925 22:38:56 dt=8192.0 s
DA-14 closest approach: 7.2428528E10 on 10 Mar 1926 08:34:08 dt=8192.0 s
DA-14 closest approach: 8.2810249E10 on 14 Mar 1927 01:18:56 dt=8192.0 s
DA-14 closest approach: 9.3121782E10 on 16 Mar 1928 11:14:08 dt=8192.0 s
DA-14 closest approach: 1.03312458E11 on 20 Mar 1929 07:30:09 dt=8192.0 s
DA-14 closest approach: 1.13342734E11 on 23 Mar 1930 17:25:21 dt=8192.0 s
DA-14 closest approach: 1.23255407E11 on 27 Mar 1931 10:10:09 dt=8192.0 s
DA-14 closest approach: 1.32954538E11 on 29 Mar 1932 20:05:21 dt=8192.0 s
DA-14 closest approach: 1.42431912E11 on 02 Apr 1933 09:31:45 dt=8192.0 s
DA-14 closest approach: 1.51667491E11 on 05 Apr 1934 17:10:25 dt=8192.0 s
DA-14 closest approach: 1.60700514E11 on 09 Apr 1935 05:22:09 dt=8192.0 s
DA-14 closest approach: 1.69469608E11 on 11 Apr 1936 13:00:49 dt=8192.0 s
DA-14 closest approach: 1.77985487E11 on 14 Apr 1937 17:21:05 dt=8192.0 s
DA-14 closest approach: 1.86235814E11 on 17 Apr 1938 22:43:13 dt=8192.0 s
DA-14 closest approach: 1.9421877E11 on 20 Apr 1939 21:15:45 dt=8192.0 s
DA-14 closest approach: 2.01856139E11 on 23 Apr 1940 00:21:21 dt=8192.0 s
DA-14 closest approach: 2.09253138E11 on 25 Apr 1941 19:35:29 dt=8192.0 s
DA-14 closest approach: 2.16334746E11 on 28 Apr 1942 20:24:33 dt=8192.0 s
DA-14 closest approach: 2.23098274E11 on 01 May 1943 07:34:25 dt=8192.0 s
DA-14 closest approach: 2.29537006E11 on 03 May 1944 03:50:25 dt=8192.0 s
DA-14 closest approach: 2.35629511E11 on 05 May 1945 07:08:50 dt=8192.0 s
DA-14 closest approach: 2.41389781E11 on 07 May 1946 20:35:14 dt=8192.0 s
DA-14 closest approach: 2.46786277E11 on 09 May 1947 20:22:26 dt=8192.0 s
DA-14 closest approach: 2.51855913E11 on 10 May 1948 20:09:38 dt=8192.0 s
DA-14 closest approach: 2.56562659E11 on 12 May 1949 16:38:26 dt=8192.0 s
DA-14 closest approach: 2.6091461E11 on 14 May 1950 02:46:26 dt=8192.0 s
DA-14 closest approach: 2.64892285E11 on 15 May 1951 17:27:30 dt=8192.0 s
DA-14 closest approach: 2.68512199E11 on 15 May 1952 13:56:18 dt=8192.0 s
DA-14 closest approach: 2.71759032E11 on 16 May 1953 20:45:54 dt=8192.0 s
DA-14 closest approach: 2.74616402E11 on 17 May 1954 17:14:42 dt=8192.0 s
DA-14 closest approach: 2.77128905E11 on 18 May 1955 00:04:18 dt=8192.0 s
DA-14 closest approach: 2.79235199E11 on 17 May 1956 16:00:02 dt=8192.0 s
DA-14 closest approach: 2.80928682E11 on 17 May 1957 14:58:10 dt=8192.0 s
DA-14 closest approach: 2.82231407E11 on 17 May 1958 17:14:42 dt=8192.0 s
DA-14 closest approach: 2.83122434E11 on 18 May 1959 00:04:18 dt=8192.0 s
DA-14 closest approach: 2.83622769E11 on 16 May 1960 14:58:10 dt=8192.0 s
DA-14 closest approach: 2.83721105E11 on 16 May 1961 20:45:55 dt=8192.0 s
DA-14 closest approach: 2.83397652E11 on 16 May 1962 20:45:55 dt=8192.0 s
DA-14 closest approach: 2.8268177E11 on 16 May 1963 16:12:51 dt=8192.0 s
DA-14 closest approach: 2.81571557E11 on 16 May 1964 10:25:07 dt=8192.0 s
DA-14 closest approach: 2.80070226E11 on 16 May 1965 16:12:51 dt=8192.0 s
DA-14 closest approach: 2.78191047E11 on 17 May 1966 08:08:35 dt=8192.0 s
DA-14 closest approach: 2.75923534E11 on 18 May 1967 11:26:59 dt=8192.0 s
DA-14 closest approach: 2.73292362E11 on 18 May 1968 03:22:43 dt=8192.0 s
DA-14 closest approach: 2.70271021E11 on 19 May 1969 17:01:55 dt=8192.0 s
DA-14 closest approach: 2.66869195E11 on 20 May 1970 22:36:51 dt=8192.0 s
DA-14 closest approach: 2.63127925E11 on 22 May 1971 15:34:27 dt=8192.0 s
DA-14 closest approach: 2.59035644E11 on 23 May 1972 10:48:35 dt=8192.0 s
DA-14 closest approach: 2.54600872E11 on 25 May 1973 05:00:51 dt=8192.0 s
DA-14 closest approach: 2.4980077E11 on 27 May 1974 11:37:39 dt=8192.0 s
DA-14 closest approach: 2.44693549E11 on 29 May 1975 09:08:19 dt=8192.0 s
DA-14 closest approach: 2.3925357E11 on 30 May 1976 20:18:11 dt=8192.0 s
DA-14 closest approach: 2.33476637E11 on 02 Jun 1977 01:53:08 dt=8192.0 s
DA-14 closest approach: 2.27410199E11 on 04 Jun 1978 17:36:04 dt=8192.0 s
DA-14 closest approach: 2.21003252E11 on 07 Jun 1979 04:45:56 dt=8192.0 s
DA-14 closest approach: 2.14293496E11 on 08 Jun 1980 20:28:52 dt=8192.0 s
DA-14 closest approach: 2.0726032E11 on 11 Jun 1981 15:43:00 dt=8192.0 s
DA-14 closest approach: 1.99937901E11 on 14 Jun 1982 09:42:28 dt=8192.0 s
DA-14 closest approach: 1.92296993E11 on 17 Jun 1983 12:48:04 dt=8192.0 s
DA-14 closest approach: 1.84396579E11 on 19 Jun 1984 06:47:32 dt=8192.0 s
DA-14 closest approach: 1.762198E11 on 22 Jun 1985 13:24:20 dt=8192.0 s
DA-14 closest approach: 1.67784645E11 on 25 Jun 1986 11:56:52 dt=8192.0 s
DA-14 closest approach: 1.59071388E11 on 28 Jun 1987 21:52:04 dt=8192.0 s
DA-14 closest approach: 1.50142894E11 on 30 Jun 1988 22:41:08 dt=8192.0 s
DA-14 closest approach: 1.4105197E11 on 04 Jul 1989 12:07:32 dt=8192.0 s
DA-14 closest approach: 1.31719537E11 on 07 Jul 1990 15:13:08 dt=8192.0 s
DA-14 closest approach: 1.22219512E11 on 11 Jul 1991 03:24:52 dt=8192.0 s
DA-14 closest approach: 1.12572015E11 on 13 Jul 1992 08:47:00 dt=8192.0 s
DA-14 closest approach: 1.02766215E11 on 17 Jul 1993 00:29:56 dt=8192.0 s
DA-14 closest approach: 9.2812403E10 on 20 Jul 1994 08:08:37 dt=8192.0 s
DA-14 closest approach: 8.2797076E10 on 23 Jul 1995 22:36:53 dt=8192.0 s
DA-14 closest approach: 7.2725815E10 on 26 Jul 1996 08:32:05 dt=8192.0 s
DA-14 closest approach: 6.2599569E10 on 30 Jul 1997 00:15:01 dt=8192.0 s
DA-14 closest approach: 5.2456862E10 on 02 Aug 1998 10:10:13 dt=8192.0 s
DA-14 closest approach: 4.2439291E10 on 05 Aug 1999 22:21:57 dt=8192.0 s
DA-14 closest approach: 3.25578097E10 on 08 Aug 2000 10:33:41 dt=8192.0 s
DA-14 closest approach: 2.29629891E10 on 11 Aug 2001 19:27:01 dt=8192.0 s
DA-14 closest approach: 1.38960159E10 on 15 Aug 2002 03:05:41 dt=8192.0 s
DA-14 closest approach: 5.9115182E9 on 18 Aug 2003 01:38:13 dt=8192.0 s
DA-14 closest approach: 1.26149901E9 on 19 Aug 2004 05:58:29 dt=8192.0 s
DA-14 closest approach: 5.7119887E9 on 21 Aug 2005 11:33:25 dt=8192.0 s
DA-14 closest approach: 1.2823339E10 on 24 Aug 2006 12:22:29 dt=8192.0 s
DA-14 closest approach: 2.05081907E10 on 29 Aug 2007 12:58:45 dt=8192.0 s
DA-14 closest approach: 3.26692332E10 on 11 Apr 2008 19:50:29 dt=8192.0 s
DA-14 closest approach: 2.83483607E10 on 13 Sep 2008 11:16:21 dt=8192.0 s
DA-14 closest approach: 2.52144128E10 on 17 Feb 2009 11:56:53 dt=8192.0 s
DA-14 closest approach: 1.71703654E10 on 14 Feb 2010 13:24:22 dt=8192.0 s
DA-14 closest approach: 9.4506547E9 on 15 Feb 2011 00:47:02 dt=8192.0 s
DA-14 closest approach: 2.60680243E9 on 16 Feb 2012 08:38:30 dt=8192.0 s
DA-14 closest approach: 3.3476168E7 on 15 Feb 2013 19:33:26 dt=512.0 s

It seems that DA14 spent most of the past century a long way from Earth. Which would suggest that it had from Feb 1918 to Feb 2013 to build up a rock train. I just so happened to start my rock train on 1 Feb 1913 just as DA14 was approaching its next rendezvous with Earth, and watched it get shredded. If I’d waited for another 10 years, I suspect I’d have seen a different picture, with a much more stable rock train.