Questions related to the Deflection of Light by Gravity determined by Soldner, Einstein and Schwarzschild

TL;DR

This paper reviews the historical and theoretical calculations of light deflection by gravity, emphasizing the role of energy and momentum conservation in determining light speed and deflection angles.

Contribution

It provides a comprehensive overview of classical and modern approaches to light deflection, highlighting the importance of conservation principles in gravitational lensing.

Findings

Speed of light can be derived from energy conservation.

Deflection angles near the Sun are consistent with theoretical predictions.

Historical calculations by Soldner, Einstein, and Schwarzschild are compared.

Abstract

Before we discuss the deflection of light in a gravitational field, we give a brief overview of some basic physical formulas on photon properties, generation and propagation. The much debated problems of the redshift and the photon propagation in a gravitational field is then considered and applied to the calculation of the speed of light. Many citations are given in direct quotations to avoid any misunderstandings. If the quotations are in German, an English translation is provided. Based on this speed, calculated and measured results are recalled on the deflection of light, with emphasis on the deflection near the Sun. We conclude that the speed of light and the deflection angle can be determined by energy and momentum conservation principles.