Short answers, pulled from the story.
Prayer is an invocation or act that seeks to activate a rapport with an object of worship through deliberate communication. In the narrow sense it refers to supplication or intercession directed toward a deity or a deified ancestor, and more generally it can give thanks or praise. It is closely associated in comparative religion with abstract forms of meditation and with charms or spells.
The act of prayer is attested in written sources as early as five thousand years ago. Some of the oldest extant literature, such as the Kesh temple hymn from around the 26th century BC, is liturgy addressed to deities. The Egyptian Pyramid Texts of roughly the same period contain spells or incantations addressed to the gods.
Approaches to prayer include the direct petition or social approach, in which a person appeals to a deity to grant requests, and the educational approach, which seeks to inculcate attitudes in the one praying rather than to influence. The rationalist approach, taken by Maimonides, trains a person to focus on divinity through philosophy and intellectual contemplation, while the experiential approach aims at a direct experience of the recipient of the prayer.
In Islam the daily obligatory prayers, called salah, form the second of the five pillars and are observed at prescribed times while facing the Kaaba in Mecca. The muezzin gives the adhan, the call for prayer, and the prayer includes standing, bowing, and prostration while glorifying and praising God. It ends with the words Peace be with you and God's mercy, after which a worshipper may offer personal supplications known as dua.
Scientific studies on prayer have produced contradictory results, and many well-controlled trials have found no effect, with some suggesting negative outcomes. A 2006 meta-analysis of 14 studies concluded there is no discernable effect, and a 2007 systematic review found inconclusive results in which the most methodologically rigorous studies failed to produce significant findings. A 2001 Mayo Clinic study and the Duke University MANTRA study both found no significant difference in recovery.
In 1872 Francis Galton conducted a statistical experiment testing whether prayer had a physical effect on the external environment. He hypothesized that the British Royal family would live longer because thousands prayed for their wellbeing every Sunday, then compared their longevity with the general population and found no difference. The experiment was probably intended to satirize and suffered from confounders, but it set a precedent for later studies.