This imam of the Eloran branch of Interstellar Islam wears a traditional garb influenced by their Terran origin, with an ornate abaya and a veil. Note the earrings made of geometry crystals.

Interstellar Islam, sometimes referred to as The Third Branch of Islam, is an undercurrent of Islam that developed among non-Terran Muslim communities during the interstellar age, first in the Traverse. With 400 million practitioners, Interstellar Islam is one the major religions of the modern era, albeit it is not as coherent and theologically isolated as the Outer Church. Indeed, and despite a few major disagreements, Terran Muslims consider Interstellar Muslims as siblings in faith, and vice versa.

A Side Road

The decentralized nature of Islam and the relative isolation of the first extrasolar settlements led to significant doctrinal and political drift compared to Terran Islam. The gradual widening of the gap led to the emergence of a set of doctrines, interpretations and rituals that, by convention, are lumped under the denomination of Interstellar Islam. It is, however, not a united sect, and most scholars consider Interstellar Islam as a constellation of planetary Islamic branches with their own interpretations of the Quran and Hadiths, a tree rather than a singular path. That being said, Interstellar Islam can still be defined by what it isn't, that is to say, Shia or Sunni. Extrasolar Muslims do not recognize the legitimacy of Earth-based religious authorities and untransformed words, that is to say Hadiths, statements of religious law or interpretations of the Quran that haven't been revised and updated by extrasolar scholars. Transformation, the displacement of belief into the physical and mental environment of extrasolar worlds, is at the heart of Interstellar Islam. Out of all the divergent religions, Interstellar Islam puts the greatest emphasis on the existence of a mental and spiritual barrier between the Earth and the rest of human worlds.

The Six Pillars of Islam

Despite its theological diversity, Interstellar Islam maintain a coherent doctrine through its Six Pillars, which take elements from Shia, Sufi and Sunni Islam. The Six Pillars are only observed in their entirety on Elora, while other communities only practice some of them, or merge them with local interpretations. 

1. The first pillar is the Shahada, or proclamation of faith. It is unchanged from the Terran proclamation: "There is no god but God and Muhammad is the messenger of God." It is said during the prayer, and it is considered acceptable to display it on the hull of Muslim-crewed spaceships. Reciting the Shahada in Arabic is the only required gesture to convert to Interstellar Islam and as such any creature capable of intelligent communication can convert.
   
2. The second pillar is the Salah, or prayer. Much like the Terran prayer, it begins with ablutions and is called by a muezzin, who either chants or displays messages. The faithful is not required to be facing Mecca, albeit some imams advise to do it whenever possible. Elorans typically face the southern pole of the planet. The prayer is often done only twice a day, with the pace being dictated by the local conditions of the planet.
   
3. The third pillar is Zakat, or almsgiving. Within the economy of extrasolar worlds, charity is rare and instead Zakat is expected to be conducted through community work. On majority Muslim worlds and stations, the Zakat is organised through specific communal organisations and syndicates, which are highly regarded in the humanitarian and scholarly spheres. 
4. The fourth pillar is Sawm, fasting, which is practised during the month of Ramadan. In the early days of Interstellar Islam, the sacred month was aligned on the Terran calendar, but is soon proved impractical, and now each planet or station has its own month of Ramadan. It is considered that one shouldn't fast more than once per Earth year, and as such a traveller who would be arriving on a planet during the month of Ramadan isn't expected to fast it they already did so within the past year. 
5. The fifth pillar is the Hajj, or pilgrimage, which is a great point of contention among Interstellar Muslims, as many spacers do not wish to or can't perform the pilgrimage to Mecca. Traditions differ regarding the Hajj, with some planetary sects relinquishing it entirely and others professing that the pilgrimage to Darb ut-Tabānah station, in the Elora system, is sufficient. Smyrnian Muslims, in line with Ismaili traditions, consider that the only valuable Hajj is the visit to the imam. 
6. The sixth pillar is Space travel : Interstellar Islam considers the geometry drive as a gift from God, and faster-than-light travel as both a way to witness the might of God (through the marvels of creations) and to perform self-betterment. It is common for a geometry drive to be displayed in the mihrab of a mosque, and many imams work as navigators.
   

Illustration for Starmoth by Tiucoo.