Organisms and Multiple Forces
Name: Sergey M.
At the same time every resting object on Earth is
participating in tree (and maybe more?) different motions in Space with
a) in the direction of Earth's revolving around its axes
with the speed about 8 km/s,
b) in the direction of Earth's orbit around the Sun with the speed about
32 km/s and c) in the direction of our Solar Systems' trajectory around
Galactic Center with the speed about 250 km/s. (I am sorry, that I don't
remember exact numbers). As a biologist I have several questions regarding
this complecs motions.
1) Can You describe, please, the common trajectory of Earth in Space
during this simultaneous movements in relations to Sun and in relations to
Galactic Center - how it will look (probably spirals) ?
2) How can we calculate the forces applied to any object on
Earth which are generated during this simultaneous movement - are they
strong or week and if they act at the same direction as Gravitational
Force acts on any object on the Earth or in opposite direction?
This question arises from my interest to calculate total forces applied on
Earth to living organisms during their development and growth which they
should overcome. For example, beside Gravitational Force, living beings
also are under big atmospheric pressure - 20 m.t/ cm^2 . May be this
movements add some additional forces?
The earth undergoes many minor wiggles and wobbles due to many causes,
tidal effects of the moon, the "off-center" of the center of mass, the
gravity of other planets... Some of these are not even well understood.
The important point is that gravity is the weakest of all forces, so its
effect decreases rapidly with distance. Consequently, the only astronomical
objects that have to be taken into account when considering gravity are:
Earth itself, the Moon, and the Sun. The effect of other planets and
celestial objects on things having small mass, like living organisms, is
extremely small, and other "small effects" are much larger -- for example
the change in atmospheric pressure, various types of electromagnetic
radiation, the pressure of soil pressure, and many more.
In order to calculate the effective amount of force for any orbital motion,
calculate mass of the object (the person) times the square of the speed,
then divided by the radius of orbit. Let's consider a 100 kg person, just
to make it simple.
Rotation of the Earth:
(100kg)(465 m/s)^2 / (6.37e6 m) = 3.4 Newtons = .764
Orbit of Earth around sun:
(100kg)(29,800m/s)^2 / (1.50e11 m) = 0.592 Newtons =
A 100 kg man feels a weight of 980-Newtons, a force of 3.4-Newtons from
Earth rotation, and 0.592-Newtons from Earth orbit of the Sun. As radius of
the orbit increases, the effect will decrease significantly. There is no
need to go beyond effects of the solar system.
Dr. Ken Mellendorf
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Update: June 2012