Nebula

A Nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases.

• Nebulae or nebulas can affect ship sensor suites or other ship equipment.
• They are Astrographic Features.

Description (Specifications)

Interstellar clouds are regions of gas, dust, and plasma that have a higher average density than the general interstellar medium. They are typically composed of about 70% hydrogen, the bulk of the remainder being helium with traces of other elements.

Basic Nebula Types

Interstellar clouds can be classified into 3 general types based on the primary form of hydrogen found within:

1. Neutral Clouds (H I regions - formed of atomic hydrogen)
2. Ionized Clouds (H II regions - formed of positively-ionized hydrogen [i.e. "Plasma"])
3. Molecular Clouds (Molecular Hydrogen - formed of H₂)

Hydrostatic Equilibrium

Under normal circumstances interstellar clouds exist in a state of hydrostatic equilibrium, in which the natural self-gravitation that would otherwise cause the cloud to collapse is balanced by the outward pressure within the cloud due to motion of the atoms and molecules that compose it. Star formation is normally caused within molecular clouds by a triggering event which locally disturbs this equilibrium, causing runaway local collapsing regions within the cloud. Such causes can be the collision of one cloud with another, or the shock-wave within the interstellar medium caused by a nearby supernova explosion.

Selected Nebulae

1. Anellet Cloud
2. The Anundarluu
3. Anterior Cloud
4. Basilisk Nebula
5. Block Nebula
6. Bourne Cloud
7. The Cauldron
8. Coalsack Nebula
9. Curtain Nebula
10. Lesser Curtain Nebula
11. Dark Cloud
12. The Dark Nebula
13. Deimos Cloud
14. Demon's Eye Nebula
15. Helix Nebula
16. Holowon Cloud
17. Hook Nebula
18. Horsehead Nebula
19. Magister Cloud
20. Inferno Nebula
21. Orion Nebula
22. North American Nebula
23. Pelican Nebula
24. Phobos Cloud
25. Rim Reach Nebula
26. Greater Shell Nebula
27. Lesser Shell Nebula
28. Separe Cloud
29. Shadow Cloud
30. Spark Nebula
31. Great Ulund Cloud
32. Little Ulund Cloud
33. Veil of The Rim
34. Verant's Head Nebula
35. Wisp Cloud

History & Background (Dossier)

No information yet available. Article section under development.

• Known to early Terran astronomers
• Known to Vilani science

Nebula Effects on Ships

Nebulae often interfere with sensors, especially commercial ship sensor suites. They can affect other ship equipment as well.

Nebula Size & Relative Location

Nebulae are typically measured in the following units:

Nebula Size & Relative Location
Size	Typical Metrics	Remarks
Astrographic Hex	Parsec or AU	These smaller nebulae are typically represented on a single astrographic hex.
Subsector	Light-year or Deshi	They are smaller nebulae by astronomic standards, but less than a subsector in size.
Sector	Light-year or Deshi	These are typical nebulae, often several subsectors in size. Some might be proto-galaxies, failed galaxies, or accreted star clusters... possibly the remants of a nova starburst.
Multi-Sector	Light-year or Deshi	These are truly massive nebulae, often several sectors in size.

References & Contributors (Sources)

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This list of sources was used by the Traveller Wiki Editorial Team and individual contributors to compose this article. Copyrighted material is used under license from Far Future Enterprises or by permission of the author. The page history lists all of the contributions.

• TBD
• Traveller Wiki Editorial Team
• Author & Contributor: WHULorigan
• Author & Contributor: Lord (Marquis) and Master of Sophontology Maksim-Smelchak of the Ministry of Science