A Nebula is a cloud of dust and gas inside a galaxy. The seemingly gorgeous cloud of stardust becomes visible when the gas glows or if the cloud reflects light from distant stars and celestial objects.
There are many types of Nebulae:
Emission Nebulae shine because their gas emits light when radiation from young stars stimulates it.
Reflection Nebulae shine because dust reflects light from stars in or around the Nebula.
Dark Nebulae appear as silhouettes because they block out light from neighboring nebulae or stars behind them.
Two types of Nebulae are derivatives of the outer layer of dying stars:
• Planetary Nebulae: It is a shell made of gas that drifts away from a dying core of a star.
• Supernova remnants: It is yet another gas shell moving away from a stellar core at great speed following a massive explosion called a supernova.
Stars are often found in clusters!
Open stellar clusters are groups of a few thousand young stars that were derived from the same cloud and are drifting apart. On the other hand, globular star clusters are densely packed, roughly spherical groups of hundreds or thousands of older stars.
Outer space has many stars and galaxies wrapped with interactions of light glowing with colors. No wonder humanity is more interested in colonizing space rather than nurturing their planet.