Nebulae are vast interstellar clouds of dust, hydrogen, helium, and other gases found in outer space. These clouds are often remnants of supernova explosions or the birthplaces of new stars. Nebulae come in a variety of shapes and sizes, with some being large and diffuse while others are compact and distinctly shaped. They are important objects of study in astronomy as they provide insight into the formation and evolution of stars and galaxies. Scientists study nebulae using telescopes that can detect different wavelengths of light, such as optical, infrared, and radio waves.