Owen Brazell Sep 25, 2005
>Owen Brazell
>
> > I definitely agree with your analysis that Delta-T is surely also
> > related to the movement of the inner core of the Earth - it makes
> > perfect sense. However, what causes changes in the movement of that
> > inner core? - for example, the movement of the magnetic poles as one
> > reflection of that movement.
>
>As I said before, we know very little about the Earth's interior, so
>the answer must be "we don't know". However, we do know some things.
>First, there's a temperature gradient within the Earth: the closer to
>the Earth's center we get, the higher the temperature will be. At
>the center of the Earth the temperature is believed to be
>approximately the same as on the surface of the Sun. This
>temperature gradient ought to cause a (very slow) convection in the
>matter of the interior of the Earth. This, combined with the Earth's
>rotation can cause a very complex circulation pattern inside the
>Earth. And any inhomogenities in the matter inside the Earth will
>make the circulation even more complex.
>
> > I definitely think that the forces are - and have to be - external,
> > since the Earth is a part of the solar system and does not simply
> > spin around in space on its own.
>
>You think so? Well, that means you also think that if these external
>forces would be absent (or negligibly small), then the matter inside
>the Earth would not move at all, despite the temperature gradient
>within the rotating Earth. So please explain why you believe such
>conditions within the Earth would not start any movement of the
>liquid or semi-liquid matter inside the Earth. If you want to
>convince others than yourself, you need to be much more explicit than
>merely saying "I think so".
>
>If you boil a pot of water on your stove, you'll see a lot of
>circulation within the water while it's boiling. Is that too due to
>forces from other planets in the solar system, rather than due to the
>heat from the stove? If you say "no", why wouldn't such a "no" also
>apply to the Earth's interior?
>
>
> > Obviously, the forces of the Sun and the Moon will be important,
> > but since I view the solar system to be just like electrons around
> > an atom,
>
>It isn't. For instance, planets do not move in fixed prescribed
>orbits like electrons in an atom do - planets can have any orbit
>(check out the orbits of all the comets and asteroids - this will
>provide many good examples of exotic orbits). And planets never
>suddenly jump from one orbit to another, like electrons in an atom
>do. Push on a planet and it'll have its orbit gradually changed -
>the stronger the push, the larger the orbital change. Push on an
>electron in an atom and nothing happens at first, until it suddenly
>jumps to another orbit.
>
> > the smaller elements may be just as important as the larger ones.
>
>FYI: in an atom all electrons are equally large. There are no
>"large" or "small" electrons....
>
>
>
> > Saying that you think you knew what "cam" I come from just because I
> > even mentioned astrology was a totally unnecessary cheap shot. Sure,
> > most mainstream astronomers themselves would never have the courage
> > to take the world astrology into their mouths. They more or less
> > deny this part of their heritage.
>
>Nonsense! Check out e.g. Sky and Telescope, which mentions astrology
>a few times every year in the magazine. Usually it mentions astrology
>in the context of the history of astronomy, and that's where it belongs.
>Occasionally, it mentions astrology when advicing stargazers on how
>to deal with contemporary astrologers -- it's unfortunate that this
>is a problem but it's nevertheless a reality.
>
> > The fact is, the history of astronomy is tightly bound with astrology
>
>Yep - and that's where it belongs
>
> > and even Kepler devised his laws primarily with astrology in mind.
>
>Astronomers of centuries ago were frequently astrology believers,
>that's true. Newton was probably the last great scientist who also
>believed in astrology (although he was more interested in alchemy),
>but already at his time scientists started to question astrology more
>and more. Newton's pupil Halley did not believe in it, and sometimes
>the two gentlemen had arguments about that.
>
>There's a big difference between ancient scientists and contemporary
>astrologers though. The ancient scientists did their best with the
>(by today's standards) very meager knowledge they had at their
>disposal. Modern astrologers ought to know better: they have a vast
>body of knowledge (which Kepler and Newton couldn't even dream about)
>available, but they choose to ignore it.
>
>
> > As written at http://www.hps.cam.ac.uk/starry/keplerastrol.html
> >
> > "Kepler disdained astrologers who pandered to the tastes of the
> > common man without knowledge of the abstract and general rules,
>
>This is precisely what contemporary astrologers do!
>
>
> > Kepler believed in astrology in the sense that he was convinced that
> > planetary configurations physically and really affected humans as
> > well as the weather on earth. He strove to unravel how and why that
> > was the case and tried to put astrology on a surer f ooting, which
> > resulted in the "On the more certain foundations of astrology
> > (1601)". In "The Intervening Third Man, or a warning to theologians,
> > physicians and philosophers (1610)", posing as a third man between
> > the two extreme positions for and against a strology, Kepler
> > advocated that a definite relationship between heavenly phenomena and
> > earthly events could be established."
>
>Kepler did his best at his time. But he was mostly wrong here. With
>the exception of the Sun, the celestial bodies do not have any
>noticeable influence on our weather. There's not even any noticeable
>correlation between the Moon's phases and the weather.
>
> > So, please do not engage in unnecessary cheap personal shots
>
>Then please don't refer to astrology.... except in its proper context,
>which is the history of astronomy.
>
> > just because I refer to harmonic ideas of the astrologers. I am in
> > very good company in thinking that earthly events may somehow be
> > related to other bodies in our solar system, even though the
> > mechanism is not known, can not currently be proven, and may indeed
> > even be a Chimera. That does not keep me from using some ideas
> > borrowed from people like Kepler.
>
>You're of course free to think whatever you want. But if you want
>to convince others than yourself, you should find convincing
>correlations between earthly events and celestial bodies. Don't
>be satisfied with "correlations" barely above the noise level
>because such "correlations" are most probably due to chance.
>
>So far there are few convincing correlation of this kind. One is the
>correlation between the Sun's position in the sky and our seasons.
>Another is the tides by the Sun and the Moon. In this case we also
>know the physical mechanism behind them. (sometimes astrologers
>argue: "humans are 75% water, therefore there are tides in the humans
>as well as in the oceans". In principle this is correct, but the
>tides in the humans are insignificant because humans are so small
>compared to oceans. As an experiment, fill your bathtub with water
>-- it'll contain more water than you do -- and let it be there for
>several days. Do this on the new moon or full moon, when the tides
>are strongest. Try to measure the tides in your bathtub - did you
>find any?)
>
>
>[ further musings on astrology snipped ]
>
>
> > You allege that Pluto can have no effect by traditional
> > gravitational theory,
>
>I never said that! I said that Pluto's influence on the Earth's
>rotation is negligible. Please note the difference between
>'negligible' and 'zero' - they are not the same!
>
>In some cases Pluto's gravitational influence is non-negligible, for
>instance the motion of Charon (Pluto's moon) is quite noticeably
>influenced by Pluto. Another possible case would be a comet
>happening to pass close to Pluto and later close to Jupiter: the
>passage of the comet close to Pluto will cause a small change in its
>orbit, and this small change can me magnified many times as the comet
>later pass close to Jupiter. So in this particular case, Pluto can
>cause the comet to end up in a very different orbit.
>
>However, the "sphere of influence" of Pluto is quite small: objects
>must be quite close to Pluto to be noticeably influenced. Earth is
>always very far from Pluto, therefore Pluto will not have any
>significant direct effect on the Earth. But a comet passing close to
>Pluto and later also close to Jupiter could perhaps collide with the
>Earth! This is of couse extremely improbable but not impossible, and
>in such a scenario, Pluto would indeed have a very significant effect
>on mankind.
>
>
> > but what about all of these other theories, where small influences
> > have disproportionate effects because they influence slightly larger
> > things, which influence larger things, which influence even larger
> > things.
>
>Now you speculate in chaos theory. Such speculations are popular
>nowadays. And in a way they are quite 'safe': since chaotic systems
>are hard or impossible to predict, you're probably safe from being
>proved wrong in your speculations.... <g> Anyway, my scenario with
>the comet above shows a possible although very improbable mechanism
>by which mankind could be strongly affected by tiny distant Pluto.
>So in a way you are right: these things CAN happen! However, now
>we're talking about something quite different than changes in Delta-T
>and if Pluto could cause these, as you originally suggested.
>
> > Ultimatley, you have a large effect. If we have dam that
> > withstands 20 feet of water or 240 inches, the 241st inch is
> > by comparison negligible, but it causes the flood so that
> > every additional inch, no matter how small,
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>?????????? Are some inches smaller than others, or what ????
>
> > is important. Without the 239th inch, the 241st is is the 240th,
> > and we have no flood.
> >
> > Pluto could be the 241st inch.
>
>Still looking for that needle in the haystack?
>
>One thing we can be quite sure of though regarding Delta-T: Pluto's
>possible but negligible influence on that is much much much smaller
>than 1/241 of the total change....
>
>In your example with the dam, we could switch from inches to
>nanometers instead. So the dam withstands 6096000000 nanometers of
>water, and at the 6096000001'st nanometer the dam will flood. And
>perhaps Pluto can be the cause of that final nanometer - you get the
>idea? Well, we have some problems here -- one nanometer of water
>will be only some 5-10 water molecules thick. And I think you agree
>with me that even a very weak wind will cause water waves millions of
>nanometers high. Not to mention roughness and small bumps in the dam
>itself, which also is millions of nanometers, or more, in size.
>
>So that small one nanometer influence by Pluto will be buried in
>"noise" caused by much larger fluctiations (millions of nanometers)
>of other kinds - fluctuations which cannot be avoided.
>
>Perhaps this example give you a good idea of what "insignificant"
>actually means. But remember that although one nanometer is an
>extremely small size, it is still different from zero.
>
>-------------------------------------------------------------------
>
>I'll end this by making a quantitative estimate of how large a
>tide Pluto could cause. You suggested one inch and I suggested
>one nanometer. Which one is most right, you or me?
>
>First, the tide by the Moon is approximately twice as large as the
>tide by the Sun. When they add upp (happens every new moon and
>full moon), the Sun's tidal contribution will be about 1/3 of
>the total tide.
>
>A tide in the open ocean is approx 0.5 meters high. In some places
>of the world, local topography can magnify this tide, and the largest
>tides evern observed on the Earth is some 10 meters high. Of this
>the Moon contributes some 7 meters and the Sun some 3 meters.
>
>Pluto's mass is about 1/1000 Earth masses while the Sun's mass is
>about 333,000 Earth masses. Thus Pluto's mass is 330 million
>times smaller than the Sun's mass.
>
>Pluto is 40 times as distant as the Sun. Since the tidal force is
>inversely proportional to the cube of the distance, this means
>that the distance factor makes the tide from Pluto 64000 times weaker
>compared to the tide from the Sun.
>
>This means that the tide from Pluto is some 2E+13 times weaker than
>the tide from the Sun.
>
>The Sun can cause tides which sometimes are as tall as 3 meters,
>which is 3E+9 nanometers. Since the tidal force from Pluto is 2E+13
>times weaker, this means Pluto can cause tides which sometimes are as
>large as 0.00015 nanometers!
>
>Yep, that's approximately 1000 times smaller than the size of a
>water molecule! It is some 10 times larger than the size of the
>nuclei of the atoms within that molecule though.
>
>This result confirms even more that the direct gravitational
>influence by Pluto on the Earth is -- extremely insignificant!
>
>And that dam of yours is now some 40640000000000 "Pluto tidal
>heights" tall -- yep, that's approximately 41 trillion ....
>
>This is a far cry from your suggested 241 "Pluto tidal heights" tall.
>But if you make the dam 1/30 nanometer tall (i.e. about 1/3 of the
>size of a water molecule), then it would become some 241 "Pluto tidal
>heights" tall ---- otoh then the dam would become so small that
>nobody would notice it. And even if you dragged out an electron
>microscope to show your "dam", no-one would want to call it "a dam".
>
>----------------------------------------------------------------
>Paul Schlyter, Swedish Amateur Astronomer's Society (SAAF)
>Grev Turegatan 40, S-114 38 Stockholm, SWEDEN
>e-mail: pausch at saaf dot se
>WWW: http://stjarnhimlen.se/
>
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