Nebulae
A nebula is a cloud of gas, dust, and other materials floating in space. The name comes from Latin meaning cloud or fog. Nebulae are stellar nurseries where new stars and planets form. When a nebula's material clumps together under gravity, it becomes denser and eventually hot enough to create a star through nuclear fusion. The leftover material forms planets and other objects around that star. Some nebulae glow brightly because hot stars are embedded within them, while others are dark clouds visible only by the starlight they block. Understanding nebulae helps us grasp how stars and planetary systems like our own are born.
Sources
- en.wikipedia.org: “Nebula (Latin for 'cloud, fog'; pl. nebulae or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust.”
- en.wikipedia.org: “Nebulae are often star-forming regions, such as 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.”
- en.wikipedia.org: “Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffused that they can be detected only with long exposures and special filters.”