You have a mistake in your translation on page 8. The joke/point is that the word for such a transformer, 柱上変圧器 (chūjōhen'atsuki), is provided the furigana reading ポールトランス (pōrutoransu). She's replying that this is analogous to writing the characters 宇宙 (typically "uchū") but reading as them コスモ (cosmo), not that the transformer has anything to do with outer space.