- In astronomy, the main sequence is a classification of stars which appear on plots of stellar color versus brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or dwarf stars, and positions of stars on and off the band are believed to indicate their physical properties, as well as their progress through several types of star life-cycles. These are the most numerous true stars in the universe and include the Sun. Color-magnitude plots are known as Hertzsprung–Russell diagrams after Ejnar Hertzsprung and Henry Norris Russell.
- Quran (Wikipedia)
The Quran, also romanized Qur’an or Koran, is the central religious text of Islam, believed by Muslims to be a revelation from God. It is organized in 114 chapters (surah) which consist of individual verses (ayat). Besides its religious significance, it is widely regarded as the finest work in Arabic literature, and has significantly influenced the Arabic language. It is also the object of a modern field of academic research known as Quranic studies.