The sky often appears red during sunrise or sunset because light travels through more of the atmosphere, scattering shorter blue wavelengths and leaving longer red ones.
While the query refers to the song, the "helpful paper" aspect may relate to the scientific phenomenon described in the title: Sky Turns Red (Extended Mix)
A red sky at night often indicates high pressure moving in, signaling dry and pleasant weather for the following day. The sky often appears red during sunrise or
The Appearance of the Sky - UCAR Center for Science Education Sky Turns Red (Extended Mix)