What’s in a name? 🤔 This riotous display of color, captured in visible and infrared light by the Digitized Sky Survey and our Spitzer Space Telescope, is Caldwell 20, also known as the North America nebula. Caldwell 20 is an emission nebula, a cloud of ionized gas that emits energy at wavelengths across the electromagnetic spectrum, causing it to glow in vibrant shades. You might guess that it’s nicknamed North America because it’s shaped similarly to the continent, but why is it called Caldwell 20? During the 18th century, French astronomer Charles Messier compiled a list of over 100 cosmic objects that might fool fellow comet hunters into thinking they had discovered new comets – the Messier catalog. In the 1980s, an Englishman named Sir Patrick Moore produced an additional list to highlight more cosmic wonders visible to amateur astronomers. His second surname was Caldwell, so he used that instead of Moore, since “M” was already taken by Messier. This nebula is the 20th item ...