Gravity

[Corey White]

In this study, we aim to shed light on the effects of extreme time
dilation on the perceived speed at which objects fall. The specific
behavior depends on the circumstances of the time dilation and the
reference frame from which it is observed. In the context of objects
falling, if extreme time dilation arises from high velocities
relative to an observer, the falling objects may appear to descend
at a slower rate. According to the principles of special relativity,
as an object approaches the speed of light, its internal processes,
including the ticking of its clock, slow down relative to a stationary
observer.

This time dilation effect causes the object's perceived motion to be
slower relative to the observer. However, from the perspective of the
time-dilated object itself, it experiences time at a normal rate, and
its fall would appear to occur at the expected speed. Nevertheless,
to an observer external to the time dilation region, the falling
object would appear to move slower than expected due to the time
dilation.

By examining the impact of time dilation on high-speed racing and the
perceived motion of falling objects, we contribute to our
understanding of relativity and its implications for various physical
phenomena. Further research can delve into the implications of time
dilation in different contexts, leading to novel discoveries and
deepening our comprehension of the universe.

Additionally, it is worth mentioning that in the theory of general
relativity, objects in free fall are considered weightless due to the
equivalence principle. The equivalence principle states that the
effects of gravity are indistinguishable from the effects of
acceleration. Consequently, when an object is in free fall, it
experiences no weight due to the balance between the gravitational
force and its inertia.

This principle provides a fundamental understanding of the behavior
of objects in free fall and their weightlessness. When considering a
scenario where an elevator is in free fall, the experience of a
person inside the elevator and an observer on the ground differ
significantly. From the perspective of a person inside the
free-falling elevator, several notable phenomena come into play.

The first is weightlessness, where the person experiences a sensation
of weightlessness as the elevator undergoes free fall. This occurs
because both the person and the elevator are subject to the same
acceleration due to gravity. Without any support force acting on the
person, they feel as though gravity is absent, resulting in a
sensation of weightlessness. Inside the elevator, all objects and
bodies are observed to be weightless. Objects float and can be easily
moved around with minimal force.

Although the laws of Newtonian mechanics still apply, the effective
force of gravity is masked by the acceleration of free fall, creating
the illusion of weightlessness. Furthermore, in free fall, both the
elevator and the person inside experience the same acceleration due
to gravity. This acceleration, typically denoted by "g" and
approximately equal to 9.8 m/s² near the surface of the Earth, does
not cause any noticeable sensation of acceleration for the person
inside the elevator since they are in a state of free fall.

The equivalence principle plays a vital role in the theory of general
relativity by establishing a connection between gravity and
acceleration. It consists of two main aspects: the Weak Equivalence
Principle and the Strong Equivalence Principle. The Weak Equivalence
Principle states that in a small region of spacetime, the motion of a
freely falling object is independent of its mass and composition.

This principle implies that all objects, regardless of their mass or
composition, fall with the same acceleration in a gravitational
field. It aligns with Galileo's observation that objects of different
masses, when released simultaneously, would fall to the ground at the
same rate in the absence of air resistance. The Strong Equivalence
Principle extends the Weak Equivalence Principle further.

It states that the effects of gravity are locally equivalent to the
effects of being in an accelerated reference frame. Consequently, in
a small region of spacetime, the laws of physics, including the
effects of gravity, are the same for an observer in a freely falling
reference frame as they would be for an observer in an inertial
reference frame in the absence of gravity.

The Strong Equivalence Principle suggests that gravity is not merely
a force acting on objects but rather a curvature of spacetime caused
by the presence of mass and energy. According to the theory of
general relativity, massive objects like stars and planets cause
spacetime to curve around them, and other objects move along curved
paths in response to this curvature.

Therefore, the equivalence principle implies that the experience of
gravity can be understood as the effect of being in an accelerated
reference frame in curved spacetime. It provides profound insights
into the nature of gravity and forms the foundation of Einstein's
general theory of relativity, which describes gravity as the
curvature of spacetime caused by matter and energy.

Particularly, the Strong Equivalence Principle suggests that being in
an accelerated reference frame is equivalent to being in a
gravitational field. Now, let's explore the behavior of gyroscopes. A
gyroscope, a spinning object with angular momentum, exhibits a
property known as gyroscopic stability, enabling it to maintain its
orientation in space even when subjected to external forces.

When a gyroscope spins rapidly, it possesses significant angular
momentum, which influences its behavior when subjected to
gravitational forces. When a gyroscope is dropped vertically, gravity
exerts a torque on it due to its asymmetrical shape and the force
acting on its center of mass. However, the gyroscope's angular
momentum resists this torque, causing it to precess.

Precession refers to the change in the direction of the gyroscope's
axis of rotation instead of falling straight down. As a result, the
gyroscope appears to fall more slowly compared to an object without
angular momentum, such as a rock falling in a linear downward
trajectory. The high spin rate of the gyroscope increases its angular
momentum, enhancing its gyroscopic stability.

This stability counteracts the gravitational torque to a greater
extent, leading to a slower apparent fall. The discovery that falling
gyroscopes can fall slower than other objects is attributed to a
physicist named Thomas Precession Searle. In the early 20th century,
Searle conducted experiments involving rapidly spinning gyroscopes
and observed their behavior when dropped from a height. He noted that
the gyroscopes appeared to fall more slowly than expected, exhibiting
a precession or circular/helical motion during their descent.

When the effects of gyroscopic stability and time dilation combine,
the effect of the gyroscope's gyroscopic stability and time dilation
can lead to an even slower apparent fall compared to both
non-rotating objects and objects not subjected to time dilation. One
experiment I have done with gyroscopes is to take a heavy wheel on a
long axle. While the wheel is spinning, the axle is rotated in a
circle. This will cause the wheel to lift up in the air pointing
vertically away from the earth, which in itself is amazing.

If the wheel or the axle rotates in the opposite direction, the heavy
wheel will point firmly to the ground and be too heavy to lift. The
effect happens in reverse in earths southern hemisphere (like water
going down a drain). And if you preform the experiment in a free
fall, the wheel on the axle will stay level & won't point up or down
at all.

To understand why this occurs I tried asking chat gpt. It broke it
down like this:

Angular Momentum: When the heavy wheel on the long axle spins
rapidly, it possesses a significant amount of angular momentum.
Angular momentum is a property of rotating objects and depends on
both the mass and distribution of mass around the axis of rotation.
The fast spinning of the wheel creates this angular momentum.
Torque: When the axle is rotated in a circular motion, it applies a
torque to the spinning wheel. Torque is a twisting force that tends
to cause a change in rotational motion. In this case, the torque is
applied perpendicular to the axis of rotation of the wheel.

Gyroscopic Stability: Due to its angular momentum, the spinning wheel
exhibits gyroscopic stability. Gyroscopic stability is the property
of a spinning object to resist any external torque that tries to
change its orientation. This resistance to torque is what allows the
gyroscope to maintain its stability and direction of rotation.

Gyroscopic Precession: When the axle is rotated, the torque applied
causes the spinning wheel to precess. Precession is the phenomenon
where the axis of rotation of a spinning object changes direction in
response to an applied torque. In this case, the applied torque
causes the gyroscope's axis to change its direction of pointing. The
direction of precession is determined by the interaction between the
applied torque and the existing angular momentum.

The precession follows a right-hand rule: if you imagine the
direction of the applied torque vector, the resulting precession will
be in the direction perpendicular to both the torque vector and the
angular momentum vector. When the wheel is spinning in one direction
and the axle is rotated in a particular direction, the torque and
angular momentum vectors align in a way that causes the gyroscope to
lift up, pointing vertically away from the Earth.

When the wheel or the axle rotates in the opposite direction, the
torque and angular momentum vectors align differently, resulting in
the gyroscope pointing downward, towards the ground.

The reversal of this effect in the Earth's southern hemisphere is not
related to the gyroscope itself but rather to the Coriolis effect.
The Coriolis effect arises due to the Earth's rotation and can affect
the behavior of rotating objects.

The Coriolis effect causes the direction of rotation to appear
reversed when observed from different hemispheres. This effect
influences phenomena such as the rotation of weather patterns and
ocean currents.

In a free fall or microgravity environment, such as during space
travel or inside a freely falling elevator, the gyroscope would not
experience the same gravitational torque as on Earth's surface. As a
result, it would not exhibit the lifting or pointing behavior you
described, and the gyroscope would stay level without pointing up or
down.

You can watch the Eric Laithwaite's experiment online here:
https://www.dailymotion.com/video/x2ya0y4