Posted: 15.04.2008

In modern science, some particles such as photon, muon, etc. are postulated as massless. But the word 'massless' here probably does not mean that they are actually possessing no mass.

'A massless particle' is an awkward translation from mathematics to English. Physicists know exactly what they mean by a 'massless' particle. A massless particle is a name they give to an element in mathematical structure. What that element represents in the real world, however, is not easy to describe and in all probabilities does not mean that the particle is completely devoid of mass.

It is well known that light is affected by gravity and bonds when passes near a massive star. It is also known that light cannot escape black holes and is, therefore, positively affected by gravity which means photons have mass.

In paramanu, we have a different situation altogether - not only, it has zero rest mass but the energy of its motion must be such that it can travel with speed much higher than that of light. This may appear, in some ways, quite contrary to the fundamental inference of relativity theory that nothing can travel faster than light. But relativity itself permits the hypothetical existence of particles called tachyons** ^{1}**, which came into existence, already travelling faster than light. In the formalisation of the special theory of relativity, tachyons have an imaginary rest mass.

Unfortunately, no one knows what an 'imaginary rest mass' means in physical terms, or what the interaction forces could be between tachyons and the ordinary particles of real rest mass.

But, there is a fundamental difference between the particles such as tachyons and paramanus. While tachyons transfer energy and momentum through space, in case of paramanu there is no transport of momentum at all but pure energy only. Since momentum is a function of mass, there is no question of transport of momentum in the case of paramanu.

- "There are particles, which at rest, would have no mass at all, a rest mass of zero…. light is made up of 'photons' - particles that have a proper mass of zero. Other particles such as 'neutrinos' and 'gravitons' also have a proper mass of zero. Particles with zero mass mean that their inertia is zero and they can be accelerated to any velocity upto infinite. In 1967, physicist Gerald Feinberg, in discussing these faster-than-light particles called then 'tachyons', from a Greek word meaning speed." (Isaac Asimov, 'SPAN' magazine, 16th July 1973).