  Mass is in the central theme everywhere from atom to galaxy. But what is mass
? Is it scalar or vector ? Apparently it appears that mass is scalar; but
relativistic mass is velocity dependent and moving mass such as photon is
vector boson. In the present paper a new concept is introduced that in general,
mass is neither scalar nor vector rather, mass is a quaternion quantity (scalar
+ vector). The concept of quaternion mass suggests that the total mass M of a
moving body is quaternion sum of : (i) the scalar(grain or rest mass) mass mg
establishing its particle behavior and (ii) the vector(photonic) mass mp
governing its wave properties. Mathematically, total quaternion mass as M = mg
+ mp, its magnitude being the Pythagorean sum as |M| = (mg2+mp2)1/2 . The
theory proposed here explains the wave-particle duality more clearly &
conceptually and gives a mathematical blend to de-Broglie hypothesis. It also
explains successfully several effects such as Compton effect and refraction of
light which could not be explained otherwise by a single theory of wave or
particle. Also explained are: Doppler effect of light, Photo-electric effect,
Uncertainty principle and Relativity. The quaternion mass concept proposed in
this paper is novel & is of fundamental importance; this could prove to be a
revolutionary concept in physics and possibly lead to new directions.
