Planetary Size

Planetary Size: Worlds are classified according to their physical size.

• Only Mainworlds (worlds or planets) of interest are recorded.
• e.g. Gas Giants are simply classified as Small (SGG) or Large (LGG).

---

Please see the following AAB Library Data articles 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)

Planetary density and size are two primary factors when determining a planet's gravity.

Planetary Size Data

The following table outlines the UWP codes for the size of a body:

Planetary Size

Code	Description	Diameter (Km)	Expected Gravity	Remarks
R	Asteroidlet / Planetary Ring (...around a world)	Multiple < 1	Microgravity (0.01 G or less)	Planetary Ring (Tiny World) Planetesimal Planetoid
D	Debris	1+ < 200	Microgravity (0.01 G or less)	Debris Field / (Tiny World) Planetoid Protoplanet
0	Asteroid / Planetary Belt (...around a star)	Multiple < 200	Microgravity (0.01 G or less)	Planetoid Belt (Tiny World) Planetesimal Planetoid Worldlet
S	Very Small	200-799	Very Low Gravity (400 km, 0.02g - 0.03g)	Very Small World
1	Small	800-2399	Very Low Gravity (1,600 km, 0.05g - 0.09g)	Small World
2	Small (e.g. Luna)	2,400-3,999	Low Gravity (3,200 km, 0.10g - 0.17g)	Small World
3	Small (e.g. Mercury)	4,000-5,599	Low Gravity (4,800 km, 0.24g - 0.34g)	Small World
4	Medium (e.g. Mars)	5,600-7,199	Low Gravity (6,400 km, 0.32g - 0.46g)	Meso World
5	Medium	7,200-8,799	Standard Gravity (8,000 km, 0.40g - 0.57g)	Meso World
6	Medium	8,800-10,399	Standard Gravity (9,600 km, 0.60g - 0.81g)	Meso World
7	Large	10,400-11,999	Standard Gravity (11,200 km, 0.70g - 0.94g)	Macro World
8	Large (e.g. Venus / Terra)	12,000-13,599	Standard Gravity (12,800 km, 0.80g - 1.08g)	Macro World
9	Large	13,600-15,199	Standard Gravity (14,400 km, 1.03g - 1.33g)	Macro World
A (10)	Huge	15,200-16,799	Standard Gravity (16,000 km, 1.14g - 1.48g)	Big World
B (11)	Huge	16,800 - 18,399	High Gravity (17,600 km, 1.49g - 1.89g)	Big World
C (12)	Huge	18,400+	Very High Gravity (17,600 km, 1.9g - 2.0g)	Big World
SGG	Small Gas Giant (no futher codes)	40,000-120,000	Macrogravity (2.01 G or higher)	Gas Giant
LGG	Large Gas Giant (no further codes)	120,000-240,000+	Macrogravity (2.01 G or higher)	Gas Giant

• NOTE-1: Please note that the size code D ( Debris ) is non-standard. It is included to cover such cases as Comet Mid-Rift (Deneb 3234), which are less than 200Km, but not part of an asteroid belt, yet important enough to have mention.
• NOTE-2: Please note that gravity values are estimations based on a standard planetary density. Planets with less or more dense cores may have very different values from the suggested average.

History & Background (Dossier)

When the UWP was created, any number of planetological figures were considered for inclusion. Initial discussion led to 16 and 32-factor descriptive chains, but theose were too many, especially for a TBD.

Basic UWP Stats

Physical Stats (...the entire sequence):

• Sp: Starport

SAH Sequence (planetology):

• S: Planetary Size (Size)
• A: Atmosphere
• H: Hydrosphere

PGL Sequence (socioeconomics):

• P: Population
• G: Government
• L: Law level

TL (technology):

• TL: Tech level

Image Repository

No information yet available.

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 Far Future Enterprises or by permission of the author. The page history lists all of the contributions.

• Marc Miller. Referee's Manual (Game Designers Workshop, 1987), .
• MegaTraveller World Builder's Handbook
• TNE World Tamer's Handbook
• The Universal World Profile
• Marc Miller. T5 Core Rules (Far Future Enterprises, 2013), 409,413.