In a 1948 letter to Lincoln Barnett, Einstein wrote; "It is not good to

introduce the concept of the mass M = m/(1-v2/c2)1/2 of a body for which

no clear definition can be given.(Photon of Mass)*

**

It is better to introduce no other mass than `the rest mass´ m.*

Instead of introducing M., it is better to mention the expression for

the momentum and energy of a body in motion." (Massless Photon)

The viewpoint above, emphasising the distinction between mass, momentum,

and energy, is certainly the modern view.* 55 years later, can

relativistic mass be laid to rest?

The energy inherent in a gram, or any other quantity of matter is

precisely the quantity of energy necessary to accelerate its mass to a

velocity equal to the velocity light by energy conversion.

This statement may be hotly disputed by some of your Earth students \who

have not yet learned to distinguish between matter and mass.

There are 2 types of mass, inertial mass, which is simply the property

of resistance to change in a state of motion, and the mass inherent in

matter, which we will call Newtonian mass because it includes all mass

which obeys the original laws laid down by Sir Isaac Newton.

The argument is to the effect that no mass can ever be accelerated to

the velocity of light since the mass would then be 'infinite' and

CONSENQUENTIONALY light, since the mass would then be 'infinite' and

consequently the energy required to produce the velocity would also be

'infinite.'

The electron has mass only because it has electric charge. As we know,

when an electric charge is

accelerated in Space, a magnetic field is produced,at the expense of the

particle's total electrostatic charge, and energy is required to produce

this conversion.

The energy 'spent' in producing this field is said to be the 'mass' of

the electron, since it is the entire cause of its resistance to

acceleration. The greater the degree of acceleration, of course, the

more intense the field, and the greater the amount of energy required to

produce it.

So we say that the electron gains 'mass' with every increase in its

velocity.

In actuality, for every increase in velocity, the electrostatic

condition decreases, and the magnetic condition increases, and at the

speed of light, all the elecrostatic condition of the electron has been

converted into a magnetic condition

If an electron could be accelerated to the velocity of light, it would

have acquired the maximum velocity with which energy can be propagated,

the conversion process completed.

It is obvious, therefore, that no amount of energy could further

accelerate this electron (with respect to its original reference point),

so it would be considered to have acquired the illusion of 'infinite'

mass.

From the formula relating relativistic mass to invariant mass, it

follows that the invariant mass of a photon must be zero, but its

relativistic mass need not be.*

The phrase "The rest mass of a photon is zero" might sound nonsensical

because the photon can never be at rest; but this is just a side effect

of the terminology, since by making this statement, we can bring photons

into the same mathematical formalism as the everyday particles that do

have rest mass.*

In modern physics texts, the term mass when unqualified means invariant

mass, and photons are said to be "massless", a photon of light

consisting of just momentum and pressure, and frequency.

The incorrectness of this assumption can be demonstrated simply by

pressing the button of a pocket laser pointer.

A beam of light will be produced which any physicist will agree has

mass, and magnetic pinch, and by very definition, moving at the velocity

of light.

Yet all the energy required is released by a small amount of chemical

change taking place within the cells of a battery

ßƒ--¹¹