Difference between revisions of "Nebula"
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== Description ([[Specifications]]) == | == Description ([[Specifications]]) == | ||
− | ''[[Wikipedia: Interstellar cloud|Interstellar clouds]]'' are regions of gas, dust, and [[Wikipedia: plasma (physics)|plasma]] that have a higher average density than the general ''[[Wikipedia: Interstellar medium|interstellar medium]]''. They are typically composed of about 70% hydrogen, the bulk of the remainder being helium with traces of other elements. | + | ''[[Wikipedia: Interstellar cloud|Interstellar clouds]]'' are regions of gas, dust, and [[Wikipedia: plasma (physics)|plasma]] that have a higher average density than the general ''[[Wikipedia: Interstellar medium|interstellar medium]]''. They are typically composed of about 70% hydrogen, the bulk of the remainder being helium with traces of other elements. Nebula can range in size from as small as 1 pc in diameter, as in the case of planetary nebulae, to over 100 pc wide in the case of some of the largest nebular clouds. |
=== Basic Nebula Types === | === Basic Nebula Types === |
Revision as of 19:55, 22 January 2019
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. Nebula can range in size from as small as 1 pc in diameter, as in the case of planetary nebulae, to over 100 pc wide in the case of some of the largest nebular clouds.
Basic Nebula Types
Interstellar clouds can be classified into 3 general types based on the primary form of hydrogen found within:
- Neutral Clouds (H I regions - formed of atomic hydrogen)
- Ionized Clouds (H II regions - formed of positively-ionized hydrogen [i.e. "Plasma"])
- 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
- Anellet Cloud
- Anundarluu, The
- Anterior Cloud
- Basilisk Nebula
- Block Nebula
- Bourne Cloud
- The Cauldron
- Coalsack Nebula
- Curtain Nebula
- Curtain Nebula, Lesser
- Dark Cloud
- Dark Nebula, The
- Deimos Cloud
- Demon's Eye Nebula
- Helix Nebula
- Holowon Cloud
- Hook Nebula
- Horsehead Nebula
- Magister Cloud
- Inferno Nebula
- Orion Nebula
- North American Nebula
- Pelican Nebula
- Phobos Cloud
- Rim Reach Nebula
- Shell Nebula, Greater
- Shell Nebula, Lesser
- Separe Cloud
- Shadow Cloud
- Spark Nebula
- Ulund Cloud, Great
- Ulund Cloud, Little
- Veil of The Rim
- Verant's Head Nebula
- Wisp Cloud
History & Background (Dossier)
Ancient Solomani astronomers originally used the Latin term "Nebula" (Lat. "Cloud") to refer to any diffuse object observed in the night skies of Ancient Terra, originally including what were later termed galaxies before their nature was discovered, as well as what were termed "nebulous stars" at the time.
- 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.[1] Sufficient study by astronomers will allow jumping into and out of the better known nebulae. There's still enough clutter that an astrogator has to aim for the destination's outer reaches.[2] Misjumps are a strong possibility under many to most conditions.[3]
Old Spacer's Comments: A nebula is quite impressive from a distance, but usually doesn't look like much close-up. The gas and dust in the typical nebula are actually very sparse, barely more dense than a pure vacuum. They look impressive from a distance only because they're so deep along our line of sight. Many spacers have reported that fuel skimming from a nebula would be about as effective as collecting water by running through fog with a bucket. Under most conditions, it would degrade sensors beyond a few dozen AU. NAFAL (>0.1c) travel would be hazardous; but it wouldn't ordinarily affect jump nor could it be efficiently skimmed without something like a electro-magnetic ramscoop. [4]
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)
This article is missing content for one or more detailed sections. Additional details are required to complete the article. You can help the Traveller Wiki by expanding it. |
- Traveller Wiki Editorial Team
- Author & Contributor: WHULorigan
- Author & Contributor: Lord (Marquis) and Master of Sophontology Maksim-Smelchak of the Ministry of Science
- ↑ Information provided to the library by Maksim-Smelchak
- ↑ Information provided to the library by Tom Chlebus
- ↑ Information provided to the library by Maksim-Smelchak
- ↑ Information provided to the library by William A. Humphrey