The giant squid is one of the most fascinating and mysterious animals on Earth. It lives in the depths of the oceans, making it very difficult to photograph, but specimens up to 18 meters long have been found. Probably known since ancient times, its figure has given rise to various legends, including that of the Kraken, an enormous sea monster capable of destroying entire ships. However, both the giant squid and the Kraken are nothing compared to the Celestial Squid, whose dimensions are instead 50 light-years!
The Celestial Squid is obviously not an animal but a nebula whose shape resembles that of the ocean giant. More specifically, the Squid Nebula, also known by the less fanciful name Ou4, is a faint bipolar emission nebula located within another larger nebula, in the direction of the constellation Cepheus. The outer nebula also takes the name of an animal, the Flying Bat.
Both nebulae are very faint and can only be captured through long-exposure photography and in specific wavelengths, so much so that the Squid Nebula was discovered very recently, in 2011. The Squid Nebula appears blue due to the emission of doubly ionized oxygen atoms, while the background nebula appears red due to the emission of ionized hydrogen.
Due to their very low luminosity, it is very difficult to determine their physical properties. According to the most recent studies, the system should be located 2300 light-years from Earth, and the structure of the Squid Nebula should be due to a complex interaction between a system of three stars expelling material into space.
Image Credit: Alex Linde.