What would happen if some force or agency, caused the Moon, to
disappear. No explosion, no debree. The Moon is just gone, like as
if some hand of God or Adam Smith, reached out and plucked the Moon
out of its orbit and flung it far away.

The Moon is responsible for keeping the Earth's Axial tilt stable and
keeping from wandering all over the place. How long would that effect
remain once the Moon is gone?

In this article, I found this:
"If you would take away the Moon suddenly, it would change the global
altitude of the ocean. Right now there is a distortion which is
elongated around the equator, so if we didn't have this effect,
suddenly a lot of water would be redistributed toward the polar
regions." Question how much water would go to the poles and how would
that affect coastal areas?
Doesn't the Moon also exert some force on the crust itself, it that
pressure would suddenly be released, would there be violent
Earthquakes?

A bigger question is how would the Moons absence effect the Earth's
orbit. If I recall correctly, the barycenter of the Earth-Moon system
is about thousand or so miles below the surface of Earth, would that
throw the Earth's orbit off to the point of flinging it totally out of
orbit if the Moon were to disappear?

Just my $0.02

Space Cadet

derwetzelsDASHspacecadetATyahooDOTcom


Moon Society - St. Louis Chapter

http://www.moonsociety.org/chapters/stlouis/

The Moon Society is a non-profit educational and
scientific foundation formed to further scientific
study and development of the moon.

: Space Cadet <kaw211@gmail.com>
: A bigger question is how would the Moons absence effect the Earth's
: orbit. If I recall correctly, the barycenter of the Earth-Moon system
: is about thousand or so miles below the surface of Earth, would that
: throw the Earth's orbit off to the point of flinging it totally out of
: orbit if the Moon were to disappear?

What is this "flinging out of orbit" of which you speak?
How could you tell if it had been done, for example.
Or what defines the notions of "orbit" and "flung out of"?

It may not be, but this *sounds* like the old "an orbit is like
a railway/tramline/whatnot in the sky, that you can "fall off" of,
or proceed at different speeds along" meme. Again, that may not be what
this "fling out of orbit" means... but it sounds like it.


Wayne Throop throopw@sheol.org http://sheol.org/throopw

On Dec 30, 11:17 pm, thro...@sheol.org (Wayne Throop) wrote:
> : Space Cadet <kaw...@gmail.com>
> : A bigger question is how would the Moons absence effect the Earth's
> : orbit. If I recall correctly, the barycenter of the Earth-Moon system
> : is about thousand or so miles below the surface of Earth, would that
> : throw the Earth's orbit off to the point of flinging it totally out of
> : orbit if the Moon were to disappear?
>
> What is this "flinging out of orbit" of which you speak?
> How could you tell if it had been done, for example.
> Or what defines the notions of "orbit" and "flung out of"?
>
> It may not be, but this *sounds* like the old "an orbit is like
> a railway/tramline/whatnot in the sky, that you can "fall off" of,
> or proceed at different speeds along" meme. Again, that may not be what
> this "fling out of orbit" means... but it sounds like it.
>
> Wayne Throop thro...@sheol.org http://sheol.org/throopw

Well, I was under the impression that the Earth & Moon are
gravitationally bound to each other and that AFAIK, the barycenter of
the Earth-Moon orbit it several thousand miles beneath the surface. If
the (weak) gravitational attraction of the Moon were to go away, this
would affect the barycenter of the Earth-Moon system, correct? Would
this seriously affect the Earth's orbit around the sun to the point
that it shifted the orbit outside of the habitable zone?

Just my $0.02

Space Cadet

derwetzelsDASHspacecadetATyahooDOTcom


Moon Society - St. Louis Chapter

http://www.moonsociety.org/chapters/stlouis/

The Moon Society is a non-profit educational and
scientific foundation formed to further scientific
study and development of the moon.

: Space Cadet <kaw211@gmail.com>
: Well, I was under the impression that the Earth & Moon are
: gravitationally bound to each other and that AFAIK, the barycenter of
: the Earth-Moon orbit it several thousand miles beneath the surface. If
: the (weak) gravitational attraction of the Moon were to go away, this
: would affect the barycenter of the Earth-Moon system, correct?

Difficult to say, since there's a singularity there requiring an
applies-to-oranges comparison. Namely, after the Event, there's
no earth-moon system, but there is one before the event.

However. Consider the velocity of the center of the earth wrt the
point it's orbiting around. That's the velocity by which the orbit
of the earth would be perturbed. Without any calculations, I'd guess
that it'd be a rather small effect on the earth's solar orbit.

: Would this seriously affect the Earth's orbit around the sun to the
: point that it shifted the orbit outside of the habitable zone?

Probably not. But a bit of tedious arithmetic could prove me wrong...


Wayne Throop throopw@sheol.org http://sheol.org/throopw

On Dec 31, 2:50 am, thro...@sheol.org (Wayne Throop) wrote:

>> Would this seriously affect the Earth's orbit around the sun to the
>> point that it shifted the orbit outside of the habitable zone?
>
> Probably not.  But a bit of tedious arithmetic could prove me wrong...

Not that tedious, at least for a BotE calc. Earth's solar orbital
velocity around the Sun is about 30 km/sec. Earth's orbital velocity
about the barycenter could be no more than 2*pi*6378 / (27*24*60*60) =
0.02 km/sec. The Moon has a trivial effect on the Earth's orbit around
the Sun (or to put it another way, if the Moon disappeared, the Earth
heliocentric orbital velocity would be "wrong" by at most 0.07%).

The stabilizing effect of the Moon on the Earth's obliquity would be
removed, but the results are long-term. In other words the effect
would be immediate, & you still wouldn't see it for tens of thousands
of years.

As to tides, will, the tidal flexing of the crust does vary all the
time, changing completely about once every six hours. So I don't see
the sudden removal of that forcing being catastrophic. Perhaps human
observable (certainly with seismometers) but not "end of the
world" (or even "end of San Francisco").

--
Brian Davis

Wayne Throop wrote:
> However. Consider the velocity of the center of the earth wrt the
> point it's orbiting around. That's the velocity by which the orbit
> of the earth would be perturbed. Without any calculations, I'd guess
> that it'd be a rather small effect on the earth's solar orbit.

Specifically, it's on the order of 1e4 km/month. By comparison, Earth's
orbital velocity around the sun is about 30 km/sec, 78e6 km/month. So
you're right, no significant change.

To answer a couple of the original poster's other questions:

The time for axial tilt swings with no moon is on the order of megayears
at least.

And given that Earth spins within the lunar tidal field every 24 hours,
and this doesn't trigger planetwide earthquakes, I don't see the sudden
disappearance of lunar tides doing so either.

For similar reasons, I doubt there'd be a major effect on the ocean;
remember solar tides are something like 1/3 to 1/2 of lunar, and they
swing every month from reinforcing to negating each other; the effect is
noticeable but not massive.

On Mon, 31 Dec 2007 07:50:25 GMT, throopw@sheol.org (Wayne Throop) wrote:

>: Space Cadet <kaw211@gmail.com>
>: Well, I was under the impression that the Earth & Moon are
>: gravitationally bound to each other and that AFAIK, the barycenter of
>: the Earth-Moon orbit it several thousand miles beneath the surface. If
>: the (weak) gravitational attraction of the Moon were to go away, this
>: would affect the barycenter of the Earth-Moon system, correct?

>Difficult to say, since there's a singularity there requiring an
>applies-to-oranges comparison. Namely, after the Event, there's
>no earth-moon system, but there is one before the event.

>However. Consider the velocity of the center of the earth wrt the
>point it's orbiting around. That's the velocity by which the orbit
>of the earth would be perturbed. Without any calculations, I'd guess
>that it'd be a rather small effect on the earth's solar orbit.

>: Would this seriously affect the Earth's orbit around the sun to the
>: point that it shifted the orbit outside of the habitable zone?

>Probably not. But a bit of tedious arithmetic could prove me wrong...

Tedius? Two minutes with a pocket calculator and a CRC handbook.

Worst case, it could increase the apehelion or decrease the perihelion
of Earth's orbit by 250,000 km, or 0.17%. With a corresponding 0.25C
decrease in mean winter or increase in mean summer temperature in the
most-affected hemisphere.

The biggest problem would likely be reworking all the calendars, to a
year that's now roughly eleven hours shorter or longer than before.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
*John.Schilling@alumni.usc.edu * for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

:: But a bit of tedious arithmetic could prove me wrong...

: John Schilling <schillin@spock.usc.edu>
: Tedius? Two minutes with a pocket calculator and a CRC handbook.

Awww, two *min*utes? Do I *got*ta?


Wayne Throop throopw@sheol.org http://sheol.org/throopw

In rec.arts.sf.science message <1199087425@sheol.org>, Mon, 31 Dec 2007
07:50:25, Wayne Throop <throopw@sheol.org> posted:
>: Space Cadet <kaw211@gmail.com>
>: Well, I was under the impression that the Earth & Moon are
>: gravitationally bound to each other and that AFAIK, the barycenter of
>: the Earth-Moon orbit it several thousand miles beneath the surface. If
>: the (weak) gravitational attraction of the Moon were to go away, this
>: would affect the barycenter of the Earth-Moon system, correct?
>
>Difficult to say, since there's a singularity there requiring an
>applies-to-oranges comparison. Namely, after the Event, there's
>no earth-moon system, but there is one before the event.
>
>However. Consider the velocity of the center of the earth wrt the
>point it's orbiting around. That's the velocity by which the orbit
>of the earth would be perturbed. Without any calculations, I'd guess
>that it'd be a rather small effect on the earth's solar orbit.
>
>: Would this seriously affect the Earth's orbit around the sun to the
>: point that it shifted the orbit outside of the habitable zone?
>
>Probably not. But a bit of tedious arithmetic could prove me wrong...

Then you should learn to do simple arithmetic.

The barycentre is within the Earth, so is less than 4000 miles from the
centre; it is actually 3000 miles, being 240000/80; the Earth does 2 pi
* 3,000 miles per month around the barycentre, and 2 pi * 93,000,000
miles per year around the Sun. The effect of the Moon on the Earth's
motion is therefore around 12 parts in 31,000. Negligible.

In fact, if the Earth were to magically vanish, the Moon's orbit around
the Sun would not change greatly - only by about 80 times what is
indicated above.


Loss of the Moon would require recalculation of the Tide Tables, and
some small ports would become unusable. The secular Gregorian Calendar
would need to be redetermined, but not urgently; the foundation of the
Date of Easter would be destroyed, but a calculation on the old basis
could be agreed. Muslims who determine the new Month by Moon sightings
would urgently need to perform a re-think. Fred E might need a new job.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v6.05 IE 6.
Web <URL:http://www.merlyn.demon.co.uk/> - w. FAQish topics, links, acronyms
PAS EXE etc : <URL:http://www.merlyn.demon.co.uk/programs/> - see 00index.htm
Dates - miscdate.htm moredate.htm js-dates.htm pas-time.htm critdate.htm etc.

: Dr J R Stockton <jrs@merlyn.demon.co.uk>
: Then you should learn to do simple arithmetic.
:
: The barycentre is within the Earth, so is less than 4000 miles from the
: centre; it is actually 3000 miles, being 240000/80; the Earth does 2 pi
: * 3,000 miles per month around the barycentre, and 2 pi * 93,000,000
: miles per year around the Sun. The effect of the Moon on the Earth's
: motion is therefore around 12 parts in 31,000. Negligible.

Well, my method was to note to myself that the distances being traversed
were more than four orders of magnitude different, in times that were
about an order of magnitude different, which would mean the disruption
was at least three orders of magnitude smaller than the orbital velocity.
At that point, I decided not to do any arithmetic, simple or not.

Though I suppose in retrospect I did do some arithmetic,
ie, "more-than-four minus about-one is something-like-three".


Wayne Throop throopw@sheol.org http://sheol.org/throopw

Dr J R Stockton wrote:

> In rec.arts.sf.science message <1199087425@sheol.org>, Mon, 31 Dec 2007
> 07:50:25, Wayne Throop <throopw@sheol.org> posted:
>> Probably not. But a bit of tedious arithmetic could prove me wrong...
>
> Then you should learn to do simple arithmetic.

Man, there sure were an awful lot of hostile responses to such an
innocuous, throwaway comment. I thought it was fairly clear he was
being facetious.

--
Erik Max Francis && max@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
All your slick moves / They were once innocent moves
-- Sade

On Jan 1, 2:54 pm, Erik Max Francis <m...@alcyone.com> wrote:

> Man, there sure were an awful lot of hostile responses to such an
> innocuous, throwaway comment.  I thought it was fairly clear he was
> being facetious.

Hostile responses to throwaway comments are the backbone of Usenet!

Damien Valentine wrote:

> On Jan 1, 2:54 pm, Erik Max Francis <m...@alcyone.com> wrote:
>
>> Man, there sure were an awful lot of hostile responses to such an
>> innocuous, throwaway comment. I thought it was fairly clear he was
>> being facetious.
>
> Hostile responses to throwaway comments are the backbone of Usenet!

No they're not!

--
Erik Max Francis && max@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
Love is the triumph of imagination over intelligence.
-- H.L. Mencken

On 2007-12-31, Brian Davis <brdavis@iusb.edu> wrote:
> As to tides, will, the tidal flexing of the crust does vary all the
> time, changing completely about once every six hours. So I don't see
> the sudden removal of that forcing being catastrophic.

Probably not catastrophic, no.

However, there is currently some permanent compression between one
pole and the other that would no longer be present. It isn't really a
lot of change in height, (less than a metre), but unlike small shifts
caused by the former 12-hour tidal cycle, it would be a permanent
deformation. The equator would compress a little while the polar
areas expanded slightly.

It looks like the effect would be similar to about a decade of average
tectonic plate movement, but I have no idea whether that extra
movement would occur over timescales of minutes, days, years or
centuries. I'm not a geologist. There's theoretically enough energy
to have it happen within seconds, but I expect that the viscosity of
the mantle would be the dominating factor - and that's very high.


- Tim

On Jan 28, 1:47 am, Tim Little <t...@soprano.little-possums.net>
wrote:
> On 2007-12-31, Brian Davis <brda...@iusb.edu> wrote:
>
> > As to tides, will, the tidal flexing of the crust does vary all the
> > time, changing completely about once every six hours. So I don't see
> > the sudden removal of that forcing being catastrophic.
>
> Probably not catastrophic, no.


Not catastrophic!! How can anyone say that!? without a moon where are
we going to go to prove our superiority over the russians? Mars? HA!
everyone knows if we go to Mars the commie martians will eat us! (it's
not called the Red planet for nothing.)

er... wait, was there a serious science question there somewhere?

In article <94759687-079c-4378-879c-d1dc5f948100@e23g2000prf.googlegroups.com>,
Fetters <juddfetters@gmail.com> wrote:
>On Jan 28, 1:47 am, Tim Little <t...@soprano.little-possums.net>
>wrote:
>> On 2007-12-31, Brian Davis <brda...@iusb.edu> wrote:
>>
>> > As to tides, will, the tidal flexing of the crust does vary all the
>> > time, changing completely about once every six hours. So I don't see
>> > the sudden removal of that forcing being catastrophic.
>>
>> Probably not catastrophic, no.
>
>
>Not catastrophic!! How can anyone say that!? without a moon where are
>we going to go to prove our superiority over the russians? Mars? HA!
>everyone knows if we go to Mars the commie martians will eat us! (it's
>not called the Red planet for nothing.)
>
Nah, the Galactic Ghoul has a preference for Soviet spacecraft
as snacks. Pretty much none of the Reds' spacecraft have ever made it
to Mars in working condition.
--
http://www.livejournal.com/users/james_nicoll
http://www.cafepress.com/jdnicoll (For all your "The problem with
defending the English language [...]" T-shirt, cup and tote-bag needs)

w/o moon, Earth would have it's next ice-age.
.. - Brad Guth


Space Cadet wrote:
> What would happen if some force or agency, caused the Moon, to
> disappear. No explosion, no debree. The Moon is just gone, like as
> if some hand of God or Adam Smith, reached out and plucked the Moon
> out of its orbit and flung it far away.
>
> The Moon is responsible for keeping the Earth's Axial tilt stable and
> keeping from wandering all over the place. How long would that effect
> remain once the Moon is gone?
>
> In this article, I found this:
> "If you would take away the Moon suddenly, it would change the global
> altitude of the ocean. Right now there is a distortion which is
> elongated around the equator, so if we didn't have this effect,
> suddenly a lot of water would be redistributed toward the polar
> regions." Question how much water would go to the poles and how would
> that affect coastal areas?
> Doesn't the Moon also exert some force on the crust itself, it that
> pressure would suddenly be released, would there be violent
> Earthquakes?
>
> A bigger question is how would the Moons absence effect the Earth's
> orbit. If I recall correctly, the barycenter of the Earth-Moon system
> is about thousand or so miles below the surface of Earth, would that
> throw the Earth's orbit off to the point of flinging it totally out of
> orbit if the Moon were to disappear?
>
> Just my $0.02
>
> Space Cadet
>
> derwetzelsDASHspacecadetATyahooDOTcom
>
>
> Moon Society - St. Louis Chapter
>
> http://www.moonsociety.org/chapters/stlouis/
>
> The Moon Society is a non-profit educational and
> scientific foundation formed to further scientific
> study and development of the moon.

On Dec 30 2007, 9:34 pm, Space Cadet <kaw...@gmail.com> wrote:
> On Dec 30, 11:17 pm, thro...@sheol.org (Wayne Throop) wrote:
>
>
>
> > : Space Cadet <kaw...@gmail.com>
> > : A bigger question is how would the Moons absence effect the Earth's
> > : orbit. If I recall correctly, the barycenter of the Earth-Moon system
> > : is about thousand or so miles below the surface of Earth, would that
> > : throw the Earth's orbit off to the point of flinging it totally out of
> > : orbit if the Moon were to disappear?
>
> > What is this "flinging out of orbit" of which you speak?
> > How could you tell if it had been done, for example.
> > Or what defines the notions of "orbit" and "flung out of"?
>
> > It may not be, but this *sounds* like the old "an orbit is like
> > a railway/tramline/whatnot in the sky, that you can "fall off" of,
> > or proceed at different speeds along" meme. Again, that may not be what
> > this "fling out of orbit" means... but it sounds like it.
>
> > Wayne Throop thro...@sheol.org http://sheol.org/throopw
>
> Well, I was under the impression that the Earth & Moon are
> gravitationally bound to each other and that AFAIK, the barycenter of
> the Earth-Moon orbit it several thousand miles beneath the surface. If
> the (weak) gravitational attraction of the Moon were to go away, this
> would affect the barycenter of the Earth-Moon system, correct? Would
> this seriously affect the Earth's orbit around the sun to the point
> that it shifted the orbit outside of the habitable zone?
>
> Just my $0.02
>
> Space Cadet
>
> derwetzelsDASHspacecadetATyahooDOTcom
>
> Moon Society - St. Louis Chapter
>
> http://www.moonsociety.org/chapters/stlouis/
>
> The Moon Society is a non-profit educational and
> scientific foundation formed to further scientific
> study and development of the moon.

Put everything into our NASA supercomputer of 2048 fast CPUs, and run
those simulations. Got any problem with that?
.. - Brad Guth