The fate of the Earth?
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From: dow on 14 Sep 2009 22:12 On Sep 14, 6:06 pm, alien8er <alien8...(a)gmail.com> wrote: > On Sep 14, 1:36 pm, dow <williamsdavi...(a)gmail.com> wrote: > > > > The bottom line is that there's no fixed reference anywhere against > > > which to measure the Earth's rotation period; it isn't even measurable > > > against itself, though its absolute rotation _rate_ is measurable. > > > Ummm.. There is (or at least there is thought to be) an absolutely non- > > rotating frame of reference, independent of observations of stars, > > etc.. It's the frame in which there are no centrifugal or Coriolis > > forces. Theoretically, the absolute speed of rotation of he earth is > > its speed relative to this frame. > > No, there's no such external reference. > > Besides, I said its _period_ (length of a day) is not independently > measurable. Its _rate_ (or speed, if you prefer) _is_ independently > measurable (say in a hermetically sealed room) with a Foucalt > pendulum. Why a Foucalt pendulum doesn't exactly measure the length of > a day is complicated and I won't try to explain; I'll refer you here > instead: > > http://en.wikipedia.org/wiki/Foucault_pendulum > > To say we've measured its period, its rotation must be timed against > an _external_ measurement point, but they all _move_. That's why I put > quotes around "fixed" stars. > > > However, there is no existing way in which this speed can be measured > > to more than a few digits of precision, so for practical purposes we > > have to use the "fixed" stars, even though we know they are not really > > fixed. > > Horsefeathers. > > Mark L. Fergerson Put two objects in space, far from any others, so that the distance between them is initially constant. Let them go and watch what happens. If they move directly toward each other, attracted by their gravity, and eventually collide exactly centrally, then they were initially not revolving around each other. They were rotationally stationary in an absolute sense. But if they go into orbit around their common centre of gravity, they were initially revolving in an absolute sense. It has nothing to do with fixed stars - maybe. Have you heard of Mach's Principle? dow
From: oriel36 on 15 Sep 2009 06:32 On Sep 14, 11:06 pm, alien8er <alien8...(a)gmail.com> wrote: > On Sep 14, 1:36 pm, dow <williamsdavi...(a)gmail.com> wrote: > > > > The bottom line is that there's no fixed reference anywhere against > > > which to measure the Earth's rotation period; it isn't even measurable > > > against itself, though its absolute rotation _rate_ is measurable. > > > Ummm.. There is (or at least there is thought to be) an absolutely non- > > rotating frame of reference, independent of observations of stars, > > etc.. It's the frame in which there are no centrifugal or Coriolis > > forces. Theoretically, the absolute speed of rotation of he earth is > > its speed relative to this frame. > > No, there's no such external reference. > > Besides, I said its _period_ (length of a day) is not independently > measurable. Grow up for godness sake and think like a man. The Earth , as a sphere, will rotate at different speeds from a maximum speed at the Equator down to zero at the geographical poles.The values for an observer at the Equator is 1669.8 km for every 15 degrees of rotation covering the complete 40,075 km circumference through 360 degrees,at 60 degrees latitude,the rotational speed is 837 km for every 15 degrees/1 hour and the same for all latitudes in the table - http://www.ncgia.ucsb.edu/education/curricula/giscc/units/u014/tables/table02.html There is a cause and effect of different latitudinal speeds which would be fairly easy to acknowledge in an era of air travel where most people are aware of the rapid transition from daylight to darkness the further towards the Equator and obversely,the longer twilights experienced towards the geographical poles.At any given moment,a location at the Equator is transiting at 1669.8 km per hour through the circle of illumination generating a swift transition to darkness while at 60 degrees latitude,the transition is longer due to the speed of 837 km or 833 km less than the Equator speed.A reasonable person,and there are not many at the moment,accepts the cause and effect with the values reflecting rotation through 360 degrees in 24 hours and then teaches their students or kids properly. Its _rate_ (or speed, if you prefer) _is_ independently > measurable (say in a hermetically sealed room) with a Foucalt > pendulum. Why a Foucalt pendulum doesn't exactly measure the length of > a day is complicated and I won't try to explain; I'll refer you here > instead: > > http://en.wikipedia.org/wiki/Foucault_pendulum > > To say we've measured its period, its rotation must be timed against > an _external_ measurement point, but they all _move_. That's why I put > quotes around "fixed" stars. > What you do is quarantine the 'sidereal time' concept as it represents a catastrophic lapse of reasoning which tries to force right ascension into daily rotation as an independent motion.The values which explain latitudinal variations in twilight or the transition through the circle of illumination via daily rotational dynamics require definite values which the 'sidereal time' junk cannot hope to supply insofar as an observer at the Equator turns through a 40,075 km distance every 24 hours or 1669.8 km per hour or 111.32 km every 4 minutes . > > However, there is no existing way in which this speed can be measured > > to more than a few digits of precision, so for practical purposes we > > have to use the "fixed" stars, even though we know they are not really > > fixed. > > Horsefeathers. > > Mark L. Fergerson Horsefeathers you say !,take off that late 17th century powdered wig and start thinking like a man or be left behind.You do not need to be too smart to appreciate how the planet ,as a sphere, rotates through 360 degrees at different speeds with definite values for each latitudinal location with definite effects following from basic planetary facts of dimensions and rotational characteristics so drop that nonsense of the 'fixed stars' and a really,really stupid 'sidereal time' reasoning. Now,the genius who built the first accurate clocks which reflect the 24 hour value explains to you on page 90-91 the outlines of the system and also something of the opposition he faced from tedious people who couldn't accept that his invention resolved the issue of longitude just as people here today do not accept the reasons why the transitional speeds from daylight to darkness are due to variations in latitudinal speeds - http://books.google.ie/books?id=8roAAAAAMAAJ&pg=PA89&dq=remarks#v=onepage&q=remarks&f=false
From: Sam Wormley on 15 Sep 2009 09:04 oriel36 wrote: > > The Earth , as a sphere, will rotate at different speeds from a > maximum speed at the Equator down to zero at the geographical > poles. Actually, that's not quite right, Gerald. the rotation rate of the earth (all parts) is exactly exactly 360° in 86,164.09+ seconds.
From: oriel36 on 15 Sep 2009 09:46 On Sep 15, 2:04 pm, Sam Wormley <sworml...(a)mchsi.com> wrote: > oriel36 wrote: > > > The Earth , as a sphere, will rotate at different speeds from a > > maximum speed at the Equator down to zero at the geographical > > poles. > > Actually, that's not quite right, Gerald. the rotation rate of > the earth (all parts) is exactly exactly 360° in 86,164.09+ seconds. I told you before,it is not a matter of right and wrong but whether that 'sidereal time' value and those who subscribe to the reasoning behind it deserve a fool's pardon or treason insofar as Western society has traits which rise above cultural or social differences or individual countries and the loss of information contained in the 24 hour value is so severe that it is far more a crisis than many would dare to believe. Unlike the collapse of the world's banking system a year ago,there is no authority in existence to handle the collapse of Western scientific traditions where planetary dynamics and cyclical phenomena are observed and reflected in that catastrophic attempt by Flamsteed to invert the references for daily and orbital motions thereby precipitating a crisis the world has not seen before,not so much the fact itself,but the dangerous tendency to jump to conclusions and disregards physical restraints which normally would put a brake on an error running amok.The current tendency to turn carbon dioxide into a global temperature dial is merely another example of the approach which began in the late 17th century and at the core of that is the 23 hour 56 minute 04 second error where right ascension was assigned a rotational dynamic it does not have. The actual person - John Harrison,explains in outlines how clocks work with planetary dimensions and rotational characteristics and it should be enough for anyone as part of a wider sprawling history of astronomical timekeeping and it is time to take a closer look at the details which see different latitudes rotate through 360 degrees at different speeds from an Equatorial maximum to a polar minimum - http://books.google.ie/books?id=8roAAAAAMAAJ&pg=PA89&dq=remarks#v=onepage&q=remarks&f=false
From: alien8er on 15 Sep 2009 14:56
On Sep 14, 7:12 pm, dow <williamsdavi...(a)gmail.com> wrote: > On Sep 14, 6:06 pm, alien8er <alien8...(a)gmail.com> wrote: > > > > > On Sep 14, 1:36 pm, dow <williamsdavi...(a)gmail.com> wrote: > > > > > The bottom line is that there's no fixed reference anywhere against > > > > which to measure the Earth's rotation period; it isn't even measurable > > > > against itself, though its absolute rotation _rate_ is measurable. > > > > Ummm.. There is (or at least there is thought to be) an absolutely non- > > > rotating frame of reference, independent of observations of stars, > > > etc.. It's the frame in which there are no centrifugal or Coriolis > > > forces. Theoretically, the absolute speed of rotation of he earth is > > > its speed relative to this frame. > > > No, there's no such external reference. > > > Besides, I said its _period_ (length of a day) is not independently > > measurable. Its _rate_ (or speed, if you prefer) _is_ independently > > measurable (say in a hermetically sealed room) with a Foucalt > > pendulum. Why a Foucalt pendulum doesn't exactly measure the length of > > a day is complicated and I won't try to explain; I'll refer you here > > instead: > > >http://en.wikipedia.org/wiki/Foucault_pendulum Did you read any of this? > > To say we've measured its period, its rotation must be timed against > > an _external_ measurement point, but they all _move_. That's why I put > > quotes around "fixed" stars. > > > > However, there is no existing way in which this speed can be measured > > > to more than a few digits of precision, so for practical purposes we > > > have to use the "fixed" stars, even though we know they are not really > > > fixed. > > > Horsefeathers. > > Put two objects in space, far from any others, so that the distance > between them is initially constant. Let them go and watch what > happens. If they move directly toward each other, attracted by their > gravity, and eventually collide exactly centrally, then they were > initially not revolving around each other. They were rotationally > stationary in an absolute sense. But if they go into orbit around > their common centre of gravity, they were initially revolving in an > absolute sense. It has nothing to do with fixed stars - maybe. The second case is simply physically impossible. It requires one or both objects be given a lateral component of motion at release. Now, one for you. Cause the objects to rotate around their own centers before release, on axes perpendicular to a line drawn between their centers. What happens? > Have you heard of Mach's Principle? Yes. It's completely irrelevant. Mark L. Fergerson |