56
R. Barrett and P. P. Delsanto
other fundamental forces (weak nuclear, strong nuclear and gravitational) into
a Theory of Everything (TOE). As we will see in later Chapters, they were
only partially successful.
3.7 O Heaven, Were Man but Constant, He
Were Perfect! [11]
Another consequence of Occam’s Razor is the belief that the laws of physics
and the fundamental constants they involve are unchanging throughout the
breadth of the Universe, that they have remained unchanged throughout its
history, and presumably will remain unchanged forever. A word of explanation is necessary here. The laws of physics often include a physical constant,
the value of which must be obtained from measurement. An example is
Newton’s Law of Gravity, where the strength of the gravitational field is given
by G, the so-called Gravitational Constant. Likewise, the speed of light in
vacuum, denoted by c, appears in many formulas in any text book of physics.
Both G and c have physical dimensions, which means that their value
depends on the system of physical units used to measure them. This is quite
arbitrary. For instance, c is normally expressed in metres per second, but
could just as well have been given in feet per second, or furlongs per fortnight. Experimentalists in nuclear physics often use the approximate value
of one foot per nanosecond for c as a guide to help them lay out detection
equipment in their time-of-flight experiments.
However, as we saw in Chap. 2, it is always possible to construct various
products and ratios of physical quantities to produce dimensionless parameters. We can carry out this procedure with the fundamental physical
constants. For instance, if we consider the ratio of the electron mass to the
proton mass, we obtain a dimensionless number that is independent of any
arbitrariness arising from the choice of units. This ratio will always have
the same value, irrespective of whether we measure the electron and proton
masses in kilograms, pounds, or any other units of mass. The value of this
ratio has therefore a more fundamental physical meaning than the individual
masses.
Another of these dimensionless fundamental constants is the Fine Structure Constant α which characterises the strength of the electromagnetic interaction between elementary charged particles. We shall discuss this constant
further in Chap. 9. Normally its value, which is known with incredible
R. Barrett and P. P. Delsanto
other fundamental forces (weak nuclear, strong nuclear and gravitational) into
a Theory of Everything (TOE). As we will see in later Chapters, they were
only partially successful.
3.7 O Heaven, Were Man but Constant, He
Were Perfect! [11]
Another consequence of Occam’s Razor is the belief that the laws of physics
and the fundamental constants they involve are unchanging throughout the
breadth of the Universe, that they have remained unchanged throughout its
history, and presumably will remain unchanged forever. A word of explanation is necessary here. The laws of physics often include a physical constant,
the value of which must be obtained from measurement. An example is
Newton’s Law of Gravity, where the strength of the gravitational field is given
by G, the so-called Gravitational Constant. Likewise, the speed of light in
vacuum, denoted by c, appears in many formulas in any text book of physics.
Both G and c have physical dimensions, which means that their value
depends on the system of physical units used to measure them. This is quite
arbitrary. For instance, c is normally expressed in metres per second, but
could just as well have been given in feet per second, or furlongs per fortnight. Experimentalists in nuclear physics often use the approximate value
of one foot per nanosecond for c as a guide to help them lay out detection
equipment in their time-of-flight experiments.
However, as we saw in Chap. 2, it is always possible to construct various
products and ratios of physical quantities to produce dimensionless parameters. We can carry out this procedure with the fundamental physical
constants. For instance, if we consider the ratio of the electron mass to the
proton mass, we obtain a dimensionless number that is independent of any
arbitrariness arising from the choice of units. This ratio will always have
the same value, irrespective of whether we measure the electron and proton
masses in kilograms, pounds, or any other units of mass. The value of this
ratio has therefore a more fundamental physical meaning than the individual
masses.
Another of these dimensionless fundamental constants is the Fine Structure Constant α which characterises the strength of the electromagnetic interaction between elementary charged particles. We shall discuss this constant
further in Chap. 9. Normally its value, which is known with incredible