FAQ faults
in [Shell]
|
Prev: Bulk moving of files
Next: B.C. and A.L.
From: Mister B on 14 Apr 2010 10:12 On 24 Mar, 03:49, bsh <brian_hi...(a)rocketmail.com> wrote: > The layman would never > think of such things as why the length of a day (which is _always_ > different) is dependant on the relative time that the northern > and southern hemispheres spend in that year's winter! (*) > (*) Because the majority of tall mountains in the world are in > the northern hemiphere, inordinate time spend in winter from one > year to the next will mean greater deposits of high-altitude snow > and ice, the distal weight of which will slow the earth's revolutions > to a very measurable degree! Are you serious?! Can you site a reference please? M
From: pk on 14 Apr 2010 10:26 Mister B wrote: > On 24 Mar, 03:49, bsh <brian_hi...(a)rocketmail.com> wrote: >> The layman would never >> think of such things as why the length of a day (which is _always_ >> different) is dependant on the relative time that the northern >> and southern hemispheres spend in that year's winter! (*) > >> (*) Because the majority of tall mountains in the world are in >> the northern hemiphere, inordinate time spend in winter from one >> year to the next will mean greater deposits of high-altitude snow >> and ice, the distal weight of which will slow the earth's revolutions >> to a very measurable degree! > > Are you serious?! Can you site a reference please? Can you post on the right newsgroup please?
From: bsh on 14 Apr 2010 18:57 On Apr 14, 7:12 am, Mister B <mark.berg...(a)thales-is.com> wrote: > On 24 Mar, 03:49, bsh <brian_hi...(a)rocketmail.com> wrote: > > The layman would never > > think of such things as why the length of a day (which is _always_ > > different) is dependant on the relative time that the northern > > and southern hemispheres spend in that year's winter! (*) > > (*) Because the majority of tall mountains in the world are in > > the northern hemiphere, inordinate time spend in winter from one > > year to the next will mean greater deposits of high-altitude snow > > and ice, the distal weight of which will slow the earth's revolutions > > to a very measurable degree! > Are you serious?! Can you site a reference please? Yes, I am serious. Alas, No, I cannot site a reference, which incidentally, I had already been trying to relocate on and off for a few years now. Although recited from memory, I believe it is accurate, although I worry why a web search of such keywords has not located it. IIRC, it was mentioned in a scholarly review of _probably_ one of the canons of calendrical analysis, viz a viz: "Calendrical Calculations" or "Calendrical Calculations: The Millennium Edition, by Edward M. Reingold and Nachum Dershowitz" http://www.calendarists.com http://emr.cs.iit.edu/home/reingold/calendar-book/papers/ http://emr.cs.iit.edu/home/reingold/calendar-book/second-edition/ When I initially read the above, I immediately recognized the truth of the assertion as logical and consistent, as well as: Isn't that cool! I previously knew that the length of the day varies, and is quite measurable (although I have always wondered what is the criterion for midnight, to the millionth of a second), but have not been as yet so motivated to refer the question to an expert in the field. Although I am an author of a date-time function library, this bit of trivia is not strictly pertainent, but it did exemplify my thesis of the nuanced complexity of those proleptic calendrical calculations presuming any kind of precision. pk wrote: > Can you post on the right newsgroup please? The question is pertainent to the original thread, is not redirected or multihomed, and is sufficiently short and sincere. In my personal opinion, I think his question here is no great sin, and certainly less than has occurred before. =Brian
From: Janis Papanagnou on 14 Apr 2010 19:45 bsh schrieb: > On Apr 14, 7:12 am, Mister B <mark.berg...(a)thales-is.com> wrote: >> On 24 Mar, 03:49, bsh <brian_hi...(a)rocketmail.com> wrote: >>> The layman would never >>> think of such things as why the length of a day (which is _always_ >>> different) is dependant on the relative time that the northern >>> and southern hemispheres spend in that year's winter! (*) >>> (*) Because the majority of tall mountains in the world are in >>> the northern hemiphere, inordinate time spend in winter from one >>> year to the next will mean greater deposits of high-altitude snow >>> and ice, the distal weight of which will slow the earth's revolutions >>> to a very measurable degree! The mass of the earth is approx. 6�10^24 kg! How much will the mass difference of the snow contribute? It doesn't sound very plausible. I've heard of earth-moon gravitational effects, and tide dynamics, are more of an issue WRT the slowing down earth. (You can find references for that.) Or did you mean something different, probably? Janis > >> Are you serious?! Can you site a reference please? > > Yes, I am serious. Alas, No, I cannot site a reference, [...]
From: Jonathan de Boyne Pollard on 14 Apr 2010 20:31
> >> >> Can you post on the right newsgroup please? >> > The question is pertainent to the original thread, is not redirected > or multihomed, and is sufficiently short and sincere. In my personal > opinion, I think his question here is no great sin, and certainly less > than has occurred before. > I wouldn't take a post that asks that and simultaneously sets followup-to to the very same newsgroup all that seriously, if I were you. (-: You're thinking of the discussions surrounding the Three Gorges Dam, by the way. If you want keywords to search on, try that name with "moment of inertia". Note that whilst the changes are indeed "measurable", they are not large. It's been calculated (by Steven Dutch, of the department of Natural and Applied Sciences in the University of Wisconsin) that melting the entirety of both polar ice-caps will only change the period of rotation by a fraction of one second. The effect of the Three Gorges Dam is said to be about 60 nanoseconds. |