The Glass "Gravitational" Lens Experiment

Abstract

Light deflection, in particular the gravitational-lens effect in its strong form, is an interesting and fascinating subject of modern physics and cosmology. Although it is conceptually articulated and complex, it is fortunately possible to approach this topic through a simplified method and analysis, involving different concepts of physics and mathematics typical of the last years of secondary school and first years of the undergraduate studies. The basic idea is the visualisation of light on curved paths under the influence of gravity. In fact, by combining optics and general relativity, it is possible to design plexiglass lenses specifically formulated to reproduce the images of any source, whose light is deflected by different types of celestial objects. The work with these lenses is moreover supported by simulations performed with the software Geogebra and the help of astonishing images from the best telescopes. All this makes gravitational lensing an excellent educational tool for teaching physics and mathematics using examples from astronomy and cosmology.