Threshold

Template:Planet Threshold is the seventh and largest planet in the Soell star system. It was the gravity anchor for Installation 04, which was situated at the Lagrange point between Threshold and its largest natural satellite, Basis.

Threshold is an immense gas giant with a diameter of 214,604 km (133,348 mi), and twelve satellites, several of which are Forerunner installations. Threshold's largest moon, Basis, has a diameter of 23,848 kilometers; the others are significantly smaller, but are nonetheless host to various Forerunner facilities. Although none of Threshold's satellites have been extensively surveyed, all but two of them appear to contain Forerunner installations, or are entirely artificial. The outposts functions are unknown, but they were likely used to provide maintenance for Installation 04.

Threshold's atmosphere is made up of white ammonia clouds, amber-colored ammonium hydrosulfide clouds, phosphorus compounds, ice crystals and other gases. Threshold is known to have storms in its atmosphere similar to the storms that occur on the planet Jupiter. The planet has a core of liquid hydrogen. Threshold's atmosphere is home to an extensive network of automated Forerunner gas mining platforms, hanging from band-like low-orbital suspension grids, though only a few of these facilities remain active in the modern era.

Threshold was a neutral location during the Human-Covenant War. Its Earth Survey Catalog number is B1008-AG.

History

Over 100,000 years ago, Threshold was a part of the sizable and extensive Forerunner ecumene. They built numerous automated gas mining complexes in the upper atmosphere of the planet, tethered to several band orbitals. Upon the discovery of the Flood, the Forerunners refitted some of the gas mines to serve as a Flood research facilities. These facilities proved only one thing: more extreme measures were needed to combat the Flood and to keep them from spreading. At the end of their war against the Flood, the Forerunners chose Threshold as a staging point for one of the Halo superweapons: Installation 04. The Halo was placed on the Lagrange point between Threshold and Basis and was used to destroy all sentient life in the galaxy, thereby halting the spread of the Flood by depriving them of available hosts.

In 2552, the Fleet of Particular Justice followed the UNSC Pillar of Autumn to Threshold, and, in a series of events, Installation 04 was destroyed. In the Skirmish over Threshold after the ring's destruction, Cortana was able to jump into slipspace with the Covenant flagship Ascendant Justice while in Threshold's atmosphere.

During the battle, the Covenant dispatched an artifact retrieval group led by Sesa 'Refumee to one of the gas mining platforms in Threshold's atmosphere. After Halo's destruction, the installation's monitor, 343 Guilty Spark, traveled to the gas mine and edified 'Refumee on the true nature of the Halos. Convinced that the Covenant religion was false, 'Refumee and his troops rebelled against the Prophets and were branded heretics as a result. The newly-appointed Arbiter, Thel 'Vadamee, and a Covenant Special Operations contingent were dispatched to silence the heretics; at the conclusion of the resulting conflict, the gas mine was dropped into Threshold's depths. High Charity and its fleet briefly visited Threshold as well, until they jumped to Installation 05.

At one point in October, the human prison ship Mona Lisa ended up picking up Covenant survivors over Threshold including one infected by the Flood. ONI began experiments with the Flood on the ship before the Flood escaped and the Mona Lisa was destroyed by a nuclear missile fired by the UNSC Red Horse. Also in the system at the time was a single Covenant ship apparently left behind to monitor or guard the Halo's remains, which were gradually being pulled into Threshold and destroyed.

After the Human-Covenant War, a 500 light-second exclusion zone was established around Threshold, with both Sangheili and human warships patrolling the region as part of the post-war treaty between those species. Uncontrolled Sentinels, volatile Halo fragments, micro-debris, malfunctioning Forerunner artifacts, and the ever-present danger of the Flood made even surreptitious exploration and scavenging too dangerous for most.

Size

Threshold is an immense gas giant, far larger than Jupiter from the Sol System. Its moon, Basis, is in fact the size of a huge rock planet. Basis' diameter is nearly double that of the Earth.

Trivia

• Threshold is described as purple in the book, Halo: The Flood, though throughout Halo: Combat Evolved and Halo 2, it is only shown as orange. Also, the planet is depicted as being light blue in the motion comic adaptation of The Mona Lisa. This may be caused by the position of the system's sun at different times or the proximity to the gas giant, or may simply be an oversight.
• In Halo: Combat Evolved, the Assault Rifle's compass arrow points at the gas giant. This suggests that Threshold's atmosphere contains a large amount of iron particles, or that the assault rifles use a digital compass and that the Alpha Halo happens to be situated so that Threshold is aligned with the rifle's north during the events of the game.

Gallery

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  Alternate preview of the gas giant Threshold.

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  Full view of the gas giant Threshold.

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  The planet Threshold.

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  A storm near the gas mine of Threshold.

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  Threshold at night.

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  Threshold with Installation 04 and John-117's lifepod in the foreground as it descends to the ring; the Milky Way galaxy can be seen in the distance.

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  Threshold as seen on the Halo PC loading screen.

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  Threshold with the remnants of the destroyed Installation 04 and the Covenant fleet in orbit.

List of appearances

• Halo: The Fall of Reach Template:First mentioned
• Halo: Combat Evolved (First appearance)
• Halo: The Flood
• Halo: First Strike
• Halo 2
• Halo: Evolutions - Essential Tales of the Halo Universe
  • The Mona Lisa
• Halo: Reach
• Halo: Combat Evolved Anniversary
• Halo: Escalation
• Halo 2 Anniversary
  • Terminals
• Halo 5: Guardians (Simulation only)