In
the third chapter, the authors cover the topics of space and frames of
reference. Newton’s concept of inertia is explained along with his invention of
the concept of absolute space. An opposing theory is also briefly discussed. In
the second half of the chapter, Einstein’s explanation of space-time is
mentioned.
Inertia
is defined as the natural resistance of every object to a change in its motion.
For example, when you are standing in a train that suddenly accelerates you
will experience a slight movement backwards. This is because your body has a
natural tendency to remain in the position it was previously at. Newton used
the concept of an absolute space that reacted to every force and produced
inertia. This space can be imagined as a substance enveloping all objects.
(above) Inertia explains why it is difficult to push
a massive object. The object’s natural tendency to resist a change in its current
state of motion (rest) prevents it from moving.
In
opposition to Newton’s method of thinking, Bishop George Berkeley stated that
the idea of absolute space is meaningless. He explained that a sphere in a void
will have no motion, because there is not a frame of reference in which motion
can be observed. When two spheres are attached by a string, motion can be
observed between the two spheres relative to each other.
Einstein’s
theory created a bond between time and space, forming space-time. In this
theory, objects can be observed from many different angles and positions in
time. Because of the success of this theory in explaining many physical
systems, it is an accepted view of the physical world.
Bibliography
Davies, Paul, and John Gribbin. The Matter Myth. New York: Orion Productions, 1992. Print
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