The phrase "Lord of the worlds" (رَبِّ ٱلْعَٰلَمِينَ - Rabbi al-'Alamin) in Surah Al-Fatiha, Ayah 2, does not explicitly confirm or deny the existence of alien lifeforms. However, classical tafsir broadens the understanding of "worlds."

Linguistically, "Al-`Alamin" (الْعَٰلَمِينَ) is the plural of "`Alam" (عَالَم), which encompasses everything in existence except Allah (Source 5). It is derived from "`Alamah" (علامة), meaning a sign, as creation testifies to its Creator (Source 6).

Scholars like Qatadah state that "`Alam" refers to "every type of creation" (Source 6). Az-Zajjaj further clarifies that it "encompasses everything that Allah created, in this life and in the Hereafter" (Source 6). While some interpretations, like Al-Farra' and Abu `Ubayd, limited it to beings with intellect (Jinns, mankind, angels, devils), others like Zayd bin Aslam and Abu Muhaysin included all creation with a soul (Source 6). The consensus, as highlighted by Al-Qurtubi, is that "`Alam encompasses everything that Allah created in both worlds" (Source 6).

Therefore, "Al-`Alamin" refers to all diverse creations, not just humanity. This broad definition allows for the possibility of other conscious or souled creations, but it does not definitively assert the existence of alien lifeforms as understood in modern science. The Quran itself states, "He is Allah, the Creator, the Inventor of all things, the Bestower of forms" (59:22-24, Source 7), indicating His expansive creative power.

📚 Sources: Classical tafsir (multi-source)