Astronomers use the bending of light due to the gravitational pull to detect large objects like planets or galaxies.

Cars and motorbikes regularly drive without light, making them impossible to detect for novice observers. Indonesians use a similar technique like astronomers whilst driving. By observing patterns in the lights of other cars, they can deduce the presence of large objects like cars or motorbikes. Based on these ‘facts’ one can make split second decisions on evasion strategies. Einstein would be so proud.