Light is Heavy

TL;DR

This paper explores the paradox of light having zero rest mass yet carrying momentum and energy, suggesting it must have gravitational mass, and offers a new perspective without presenting new results.

Contribution

It provides a novel perspective on the mass paradox of light, challenging traditional interpretations without deriving new theoretical results.

Findings

Light carries momentum and energy despite zero rest mass

Light must have gravitational mass due to the principle of equivalence

Offers a new perspective on the mass paradox of light

Abstract

Einstein's relativity theory appears to be very accurate, but at times equally puzzling. On the one hand, electromagnetic radiation must have zero rest mass in order to propagate at the speed of light, but on the other hand, since it definitely carries momentum and energy, it has non-zero inertial mass. Hence, by the principle of equivalence, it must have non-zero gravitational mass, and so, light must be heavy. In this paper, no new results will be derived, but a possibly surprising perspective on the above paradox is given.