In Christian stories, "Hell" is hot, full of fires and typically "down" or deep underground.
In science, we know that the inside of the earth is magma, hot and melting metals.
However, given timing, one would expect that the Christian characterization of "Hell" came before we knew the center of the earth was molten magma. Is that so?
What were the relative timelines on the Christian story of Hell and our scientific understanding of the deep earth and magma? Why is there a co-incidence of these two stories if the Christian story came so much before our science understanding?
It's a coincidence. The downward direction of "hell" traces its roots to sheol, the old Jewish underworld, which was original conceived as a dark cavernous realm of the dead, roughly equivalent to the Greek conception of Hades (which was used in place of "sheol" in the Greek translations of the Hebrew scriptures). The fiery aspects of hell comes from Gehenna, a valley near Jerusalem which had long been associated with fire and wickedness; the followers of Molech were said to have burned their children there as sacrifices to their god. The site eventually became a metaphor for the punishment and / or destruction of the soul after death. When the Christian gospels describe "hell" as fiery, the word being used in the original language is almost certainly Gehenna. Later Christian texts, further removed from the environs of Jerusalem, build upon that metaphor without actually mentioning Gehenna directly though.