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Bilium is a planet in the Ooromine System. Its only mention was in the Space Pirate observatory in Metroid Prime.

Bilium
The planet Bilium.
Location	Ooromine System
Discovery date	2X12
Mass	3.8 trillion teratons
Class:	XIII Planet[1]
Size	25,000,000[1]
Atmosphere	Carbon Dioxide, Methane, Oxygen, Hydrogen trace gases.
Distinct features	Planetwide occupation of Miteralis has expired all life on the planet.

[edit] Metroid Prime Scan

Planet Bilium
Mass: 3.8 trillion terratons.

Profile: QUARANTINE
Atmosphere is rife with Miteralis, a sentient gaseous Global Exterminator virus.

Planets in the Metroid Series
Note: Bolded Planets were visited by Samus Aran
Tetra Galaxy
Alinos | Arcterra
Ooromine System
Bilium | Ooromine II | Twin Tabula | Zebes | Tallon IV
Federation Solar System
Bryyo | Norion | Elysia
SR 388 System
SR227 | SR388
Other
Aether | Aliehs III | Bes III | Cylosis | Earth | Jovia XII | Earth Colony K-2L | Mondreus | Phaaze | Phrygis | Pirate Homeworld | Tivus | Vho | Wotan VII