| Nebula Classifications (Cont'd) |
| Emission Nebula |
| Micro-Nebula |
| Planetary Nebula |
| Proto-Nebula |
| Protostellar Nebula |
| Stellar Nursery |
 |
 |
 |
 |
 |
 |
| Emission Nebulae are clouds of ionized plasma which emit various colors of light. The most common source of ionization comes from high energy photons radiating off large nearby stars. Due to the prevalent amount of hydrogen present in most interstellar gas and its low energy requirement for ionization, most emission nebulae are red. If more energy is available, other elements can be ionized and green and blue nebulae are possible. Most emission nebulae are about 90% hydrogen, with traces of other gases such as helium, oxygen, nitrogen, and other elements. |
| Little is known about Micro-Nebulae and how they are formed. There has not been sufficient research gathered on these nebulae as they are not a common phenomena in the galaxy. |
| A Planetary Nebula is formed when an extremely hot star, such as a supergiant, ejects a shell of gas exposing the star's inner core. Planetary Nebulae have nothing to do with planets - they are only so called because of their resemblance to a planet. Ships passing too close to the ring of gas would experience turbulant trajectory and possible engine failure. The first recorded analysis of a Planetary Nebula was in 2151 by Captain Archer and the NX-01. |
| Newly forming interstellar dust clouds are commonly called Proto-Nebulae. These nebulae contain the building blocks for stars and planets. Sensors do not function well, however shields have proven stronger while inside. It is unknown why this happens. |
| Protostellar Nebulae contain very high levels of flux. Any starship that passes through one of these clouds of dust and gas is hidden from sensor scans for 72 hours, whereafter shields begin to fail and the engines overload. |
| A Stellar Nursery is a nebula in which multiple stars are being formed. Intense ultraviolet light is often given off by the forming stars. It has been advised that ships not pass within 250,000 kilometers of a stellar nursery as the radiation from the star clusters interferes with ship systems, such as life support and shields. The first charted Stellar Nursery was made by the NX-01 Enterprise in 2151. |