Re: Precession

From: don findlay (don_at_tower.net.au)
Date: 10/25/04 

Date: 25 Oct 2004 16:59:34 -0700

"Carsten Troelsgaard" <carsten.troelsgaard@mail.dk> wrote in message news:<417d2524$0$99220$edfadb0f@dread15.news.tele.dk>...
> "Bigdakine" <bigdakine@aol.comGetaGrip> skrev i en meddelelse
> news:20041025050405.22420.00001230@mb-m06.aol.com...
>
> snip
>
> > >To be frank, I never gave 'black holes' or other astronomical considerations
> > >much attention...
> > >except for handier problems like precession. Precession seems to be 'within
> > >my reach' though my book
> > >of physics says, that the Earth precesses a whole revolution in 26.000 years
> > >- I find it somewhat
> > >difficult to believe that the Earth's spin-axis at part of this time is lying
> > >in the plane of the
> > >Sun-Earth rotational plane and thus effectively give no intermediate seasons
> > >through the year (or
> > >rather half a year day/night for pole positions). I probably better get used
> > >to the idea - unless
> > >someone can correct my physics.
> >
> >
> > If you're thinking that precessions means that at some point the Earth's
> > rotation axis lies in the ecliptic plane, then you have the wrong idea.
> >
> > Precession in this case means that Earth's rotation axis makes one revolution
> > about the figure axis in ~26000. The spin is inclined 23.5 degrees. Absent any
> > other effects, that 23.5 degrees stays fixed. Precession, or more specifically,
> > precession of the equinoxes, does not mean the Earth was once rolling like a
> > bowling ball in its orbit.
>
> Thanks. I achually knew that, but didn't figure it out from Young & Freedman, 'University Physics'
> and it's calculations of gyroscopic precession.
> I finally found some in-depth descriptions at 'celestrial mechanics', if anyone is curious.
>
> http://orca.phys.uvic.ca/~tatum/celmechs/celm6.pdf
>
> I achtually got cought up in reading about an alternative proposal
>
> http://www.binaryresearchinstitute.org/introduction/binary.shtml
>
> It's difficult to read it critically as one kind of has to learn the whole astronomical package to
> do so. I still havn't seen the 26.000 year precession-cycle calculated from the differential forces
> acting (as a torque) on Earth - but the precession of a gyro is a strong indicator that it achtually
> happens.
>
> Carsten

What's this got to do with anything? (The Earth spinning). Are you
losing the plot Carsten? Milankovitch cycles. Fossil weather.
Indeed. Next it will be ice caps and global warming. Is this how a
real scientific geologist wakens up to the fact of the Earth's
rotation? (Jeesus!) ('ccreationists). Eye_arsk_ya.

Rumble tumble in the grass
makes Carsten get all gluey (I mean cluey)
Something something something else
and something's F^%$# screwy

 
> > However, the Earht's inclination w.r.t the ecliptic (obliquity) does change,
> > and this is an importatn component in Milankovich cycles.

Relevant Pages

  • Re: Doomsday Dec 21 2012
    ... planetary alignment. ... This suppose to be the end of Earths precession, occurs every 26,000 years. ... The Earth's rotation axis is not fixed in space. ... Earth was flat! ...
    (sci.astro.amateur)
  • Re: Precession
    ... >> rotation axis lies in the ecliptic plane, then you have the wrong idea. ... >> Precession in this case means that Earth's rotation axis makes one ... rough calculations can be found in various undergraduate geophyscis ... "Creationists aren't impervious to Logic: ...
    (sci.geo.geology)
  • Re: Precession
    ... >except for handier problems like precession. ... >Sun-Earth rotational plane and thus effectively give no intermediate seasons ... Precession in this case means that Earth's rotation axis makes one revolution ... "Creationists aren't impervious to Logic: ...
    (sci.geo.geology)
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