Hydrosphere

The Hydrosphere represents (Hydrographics) or the liquid content of a world, usually water on a conventional life-supporting world (planet).

• For normal worlds, the hydrosphere will be water; on other worlds with exotic, corrosive, or insidious atmospheres, it may be other liquids or fluids such as ammonia.

Library Data Referral Tree

Please refer to the following AAB Library Data for more information:

• Observing Charted Space
  • Universal World Profile (UWP)
    • Starport (Sp)
    • Planetary Size (S)
    • Atmosphere (A)
    • Hydrosphere (H)
    • Population (P)
    • Government (G)
    • Law Level (L)
    • Tech Level (TL)
  • PBG Sequence
    • P: Pop Multipliers
    • B: Belts
    • G: Gas Giants
    • TZ: Travel Zone
  • COG Sequence
    • C: Climate
    • O: Orbit
    • G: Gravity
  • Other System Data
    • Allegiance Code (AC)
    • Base Code (BC)
    • Cultural Extension (Cx)
    • Economic Extension (Ex)
    • Importance Extension (Ix)
    • Sophont Code
    • Trade Classification (TC)

Description (Specifications)

Some worlds with vacuum atmospheres may have hydrographic percentages greater than 0 indicating that the world has ice caps present; the water will not be freestanding liquid. A Desert World may have up to 5% free-standing water and still be considered a Desert World. Conversely, a Water World may have a 96% hydrosphere and still be considered a Water World.

Hydrographic Code Table

Hydrographic Codes
Symbol	Code	Description	% Surface Water Smelchakian School	% Surface Water Tymesian School	Remarks
	0	Desert World	0	0 - 5	It is a super arid (anhydrous) environment.
	1	Dry World	1 - 10	6 - 15	It is an arid (near anhydrous) environment.
	2	Dry World	11 - 20	16 - 25	It is a standard (wet) environment.
	3	Wet World	21 - 30	26 - 35	It is a normative (wet) environment.
	4	Wet World	31 - 40	36 - 45	It is a normative (wet) environment.
	5	Average Wet World	41 - 50	46 - 55	It is a normative (wet) environment.
	6	Wet World	51 - 60	56 - 65	It is a normative (wet) environment.
	7	Wet World	61 - 70	66 - 75	It is a normative (wet) environment.
	8	Very Wet World	71 - 80	76 - 85	It is a standard (wet) environment.
	9	Very Wet World	81 - 90	86 - 95	It is a marine (near superhydrous) environment.
	A	Water World	91 - 100	96 - 100	It is a supermarine (superhydrous) environment.

History & Background (Dossier)

Sophonts are known for having opinions and hydrology and hydrography are no different. Two alternate schools of interpreting the UWP arose within the early Third Imperium and are still argued about across Charted Space. Which is better? Only you can say...

What Hydro Rating should Terra be?

Another longstanding argument has been: What hydro rating should Terra be?

• The dispute rages on, but values of 6 to 8 are most common.

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.

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 Mongoose Publishing or by permission of the author. The page history lists all of the contributions.

• Marc Miller. Worlds and Adventures (Game Designers Workshop, 1977), 4, 6.Marc Miller, Robert Eaglestone, Don McKinney. Worlds and Adventures (Far Future Enterprises, 2019), 4, 6. (Classic Traveller Book 3)
• Joe Fugate. Grand Survey (Digest Group Publications, 1986), 19.
• Marc Miller. Referee's Manual (Game Designers Workshop, 1987), TBD.
• Geir Lanesskog. World Builder's Handbook (Mongoose Publishing, 2023), TBD.Joe Fugate, J. Andrew Keith, Gary L. Thomas. World Builder's Handbook (Digest Group Publications, 1989), TBD.
• Frank Chadwick, Dave Nilsen. Traveller: The New Era (Game Designers Workshop, 1993), TBD.
• Marc Miller. Marc Miller's Traveller (Imperium Games, 1996), TBD.
• Loren Wiseman. GURPS Traveller Core Rules (Steve Jackson Games, 1998), TBD.
• Martin Dougherty, Hunter Gordon. The Traveller's Handbook (QuikLink Interactive, 2002), TBD.
• Citation Missing - Mongoose Traveller Main Rulebook
• Marc Miller. T5 Core Rules (Far Future Enterprises, 2013), TBD.
• Matthew Sprange. Core Rule Book (Mongoose Publishing, 2016), TBD.
• Traveller Wiki Editorial Team
• Author & Contributor: Lord (Marquis) and Master of Sophontology Maksim-Smelchak of the Ministry of Science