Charles Messier was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the Messier objects, referred to with the letter M and their number between 1 and 110. Messier's purpose for the catalogue was to help astronomical observers distinguish between permanent and transient visually diffuse objects in the sky.
Charles Messier, c. 1770
Messier's grave in Père Lachaise
The Orion Nebula as drawn by Messier, and which he gave the designation M 42 in his catalogue
Commemorative plaque in Messier's hometown of Badonviller
A nebula is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions, the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter and eventually become dense enough to form stars. The remaining material is then thought to form planets and other planetary system objects.
True color image of the Trifid Nebula, showing complex gas and plasma structure
Portion of the Carina Nebula
NGC 604, a nebula in the Triangulum Galaxy
Herbig–Haro HH 161 and HH 164.
