Westerhout 43, also known as W43, is a region of star formation of our galaxy located in the constellation of Aquila at a distance of 6 kilo-parsecs (nearly 20,000 light-years) of the Sun, that is considered the region of the Milky Way that is most actively forming stars. Despite this, however, it is so heavily obscured by the interstellar dust that it is totally invisible in the optical and must be studied using other wavelengths that are not affected by it, such as the infrared or the radio waves.