Good morning Sir: I was wondering if the earth's rotation were halted and instead all other objects in the universe rotated the other way around earth's axis at the rate of one rotation every 24 hours, do you know if the earth would continue to maintain the bulge around its equator? rhanson
Hello rhanson:
Historically, your question may be found amongst the many imaginary thought experiments of Ernst
Mach and Albert Einstein. Perhaps they once tried lying on a rotating playground turntable and
imagined what it would be like if the turntable was not rotating in one direction but instead the
entire Universe was rotating in the opposite direction, just as you describe.
From imaginations such as these, Einstein reached the conclusion that there is no difference between
the outward-directed "centrifugal" forces present during an event where the Universe is fixed and
the turntable is rotating, or the turntable is fixed and the Universe is rotating. He referred to
the "sensible" outward-directed force being experienced by an off-center observer in each case
as being due to an outward-directed "gravitational effect" resulting in an outward-directed
"gravitational field" not recognized by Isaac Newton's law of gravitation.
Unfortunately, in their effort to upstage the absolute nature
of Isaac Newton's work, Mach and Einstein could not allow themselves to consider the generation of this outward-directed
acceleration/Reaction force within a rotating object as having anything to do with the object's inward-directed
acceleration as it orbited the turntable's axis of rotation. So they looked to the stars for
a relative answer. (See Article VI: Gravitation =
Acceleration?)
In reality, there "sensibly" does exist a supporting reaction force from within
an object's matter that is equal in magnitude and opposite in direction to every
type of action force that is causing acceleration for that object. If it were not for the presence of this acceleration/Reaction
force of matter, in a frictionless environment, it would not even be possible to apply an external
acceleration/Action force against the object's surface. Newton's LAW III
and Rule 7 of Article X, Universal Physics Rules
for Force and Motion dictate this to be so. (For an in-depth look at the nature of reaction forces read
Article XI,
Reaction Forces.)
We know from Article III that one cannot push against an object with more or
less force than the object pushes back in response. Thus the forces present between two contacting
objects are always mutual. In a linear event when you are riding as a passenger in a car, or on an
airplane, that is speeding up (positive acceleration) along horizontal pavement, as much as the back of
your
seat is applying a forward-directed acceleration/Action force against your body, your body is
applying a rearward-directed acceleration/Reaction force in response. Insert a compression scale
between the seat and your back and a helper will be able to observe the scale's compression between
these two equal and opposite forces. I labor over this point because the rearward-directed force is
not currently recognized as your body's a/R force that it truly is, always has
been, and always will be.
With Einstein's rotating turntable, the outward-directed force the observer is sensing is
this same acceleration/Reaction force you sense while accelerating horizontally in
any one direction in a vehicle. Only
here on Einstein's rotating turntable, the direction of the observer's acceleration keeps changing to
always remain pointed toward the turntable's axis of rotation. It is no coincidence that the
acceleration/Action force the observer is experiencing is also directed toward this same axis
of rotation. Thus here on Einstein's rotating turntable, the inward-directed acceleration/Action
force impressed as an external (contact) force on the observer that is the cause of this event is equally supported by the outward-directed acceleration/Reaction force
being reactively and internally generated within each component of the observer's accelerating matter.
The recognition and understanding of this common, everyday action/reaction pair
of acceleration forces is what eluded both Ernst Mach and Albert Einstein.
Unfortunately for Mach's and Einstein's theories, rotation is an absolute event as proved long ago
by Newton's rotating bucket of water experiment which is well described in PRINCIPIA. When
Einstein's turntable is rotating, a/A forces and mutually supporting a/R forces are
both present. When the turntable
is not rotating, a/A forces and mutual a/R forces are both absent, regardless of whether the
rest of the matter in the Universe is "whirling" or not "whirling", or
even present or not present.
How do I know for certain that Mach and Einstein are wrong regarding the outward-directed forces
present during the acceleration of a rotational event? Since acceleration/Reaction
forces are present during examples of linear acceleration, there is every reason to recognize
these same a/R forces as being present during rotational examples of centripetal acceleration.
In both types of accelerational events it is crucial to recognize that the
acceleration/Reaction forces present are always directed opposite to the
direction of the acceleration. Thus we may correctly conclude that the
acceleration/Reaction forces testably present are never the cause of any
accelerational event. Thus it is never correct to say in a linear
accelerational event, that the backward-directed acceleration/Reaction force
present is the cause of the test object's forward-directed acceleration.
Equally so, it is never correct to say in an inward-directed (centripetal)
accelerational event, that the outward-directed (centrifugal)
acceleration/Reaction force present is the cause of the test object's
inward-directed acceleration. Such acceleration/Reaction forces are merely
supporting the acceleration/Action forces present which always stand firm as
the cause of the forward-directed acceleration in the linear event and the
inward-directed acceleration in the circular event. It is hard to recover
from getting the direction of one's action forces backwards. Such recovery
never happened for either Ernst Mach or later for Albert Einstein. This
simple undeniable fact renders as useless their theoretical work in this
area. With our
new understanding and recognition of an object's a/R force that is testably present during rotational
events, there is simply no role left for Mach's and Einstein's imaginary
"dynamic gravitational effect" forces to fill.
As Earth rotates in an absolute manner about its own axis, an inward-directed acceleration occurs to
Earth's matter that reaches a maximum along the surface of Earth's equator. The force causing this inward-directed
acceleration is but a small portion of the matter's overall inward-directed action force of gravitation
toward Earth's center of matter. This small, inward-directed, gravitational,
internal acceleration/Action force is
supported by and terminates against an equally
small, outward-directed, internal acceleration/Reaction force effectively reducing the
external (contact) force of the object's
equatorial weight as compared to its polar weight by a ratio of about 329/330. Thus Earth's matter
bulges outward around her equator since her equatorial matter is a little
lighter in weight-force reducing the compression of the column
of matter all the way down to Earth's core. So this nearly 4000 mile tall
column of equatorial matter stands higher above Earth's core as it is balanced
by the lesser quantity of the heavier and shorter column of matter located
at either of Earth's poles.
Reserving the short answer to the end, no equatorial bulging of Earth's matter will occur if
Earth's rate of rotation is reduced to zero, regardless of whether the rest of the Universe is whirling or
not whirling, or for that matter, present or not present. Since rotation
is an absolute event, as well-proven by Newton's Bucket, Earth's current
rotation need only be compared to Earth when it is not rotating. No other
object in space is required to exist in order for this determination to be made
of the absolute nature of rotation.
All Mach and Einstein accomplished with their imaginative thought experiments was to generally cloud the greatness of the work of Isaac Newton. Newton's work was not perfect for, among other things, in it he granted reality to imaginary "inertia". (See Article I, The Reality of Newton's Inertia.) But Mach and Einstein did not succeed in correcting any portion of Newton's work. Overall, Newton got most everything right while Mach and Einstein got most everything wrong. Yet Modern Physics accepts nearly the opposite position as true where Mach's and Einstein's work is allowed to stand against logic as a correction to Newton's work.
Curious, is it not, how such general misunderstandings are allowed to prevail. In truth, Modern Physics is, at best, an Interim Physics that is being held up solely by the combined strengths of authority and tradition. It is good that Galileo and Newton are not here to witness what has become of the great science of their origination: a science where their immense contributions now amount to little more than misrepresented footnotes. With the best of intensions they handed us the ball along with some thoughtful instructions. Unfortunately Modern man has never been very good at reading, understanding, and following instructions.
Thanks rhanson for the fine question about the absolute nature of centripetal acceleration.
Ethan Skyler
P.S. Be careful of those playground turntables. My son Robert fell off one and rolled underneath.
A piece of steel angle iron under the turntable struck him on the hip causing a painful injury.
Copyright © 2001 - 2008 by Ethan Skyler. All rights reserved.
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