Interstellar Medium and Nebulae

The interstellar medium (ISM) refers to the matter that exists in the vast spaces between stars in our galaxy, composed of gas, dust, and cosmic rays. Nebulae are specific regions within the ISM, often seen as colorful clouds, where gas and dust gather. They can be sites of star formation (like stellar nurseries) or remnants of dead stars. Nebulae come in various types, including emission (glowing gas), reflection (scattering starlight), and planetary nebulae (shells of gas ejected from dying stars). Both the ISM and nebulae play crucial roles in the life cycle of stars and galaxies.