Caused by backscatter of sunlight against interplanetary dust, this German word refers to a phenomenon that’s also known as “counterglow”. French astronomer Esprit Pezenas first noted the phenomenon in 1730, but it got the name from German explorer Alexander von Humboldt after traveling through South America between 1799 and 1803. Light pollution renders the gegenschein invisible in most inhabited regions of the planet in the 21st Century.
