Gravitation Lensing is a concept that explains the bending of light around the massive objects in space. Albert Einstein proposed this concept in his General Theory of Relativity.
The bending of light around the massive object is due to the space-time curvature or distortion created by the massive objects. Due to the bending of light around the massive objects, it appears that the position of stars could be different than its actual, apparent position.
Fortunately, you don’t need to travel to space to understand this phenomenon. In this activity, we will simulate gravitational lensing using wine glass to understand this phenomenon better.
Average Time:10-15 Minutes
Wine Glass Graph Paper
Graph Sheet (Download) Printouts of a star/galaxy map (Download)
This experiment doesn’t simulate the real bending of light; instead, it demonstrates the concept of bending using light refraction from the circular base of a wine glass. The circular bottom of the wine glass acts as Lense.
As you look through the wine glass base, you will Notice the “straight” graph lines bend as you move the glass slowly across the paper. Lines in the graph that are closer to the center of the base will curve more than lines close to the edge of the base.
Likewise, the gravitational lens acts like a circular lens curving the light of the stars behind it. According to Einstein, the massive objects exert a stronger force, causing the light to bend more sharply. In a more massive place like black holes, the light bends so much that it never escapes the gravitational force.