- The earliest known case of human cremation, known as the "Mungo Lady," occurred at least 20,000 years ago in southeastern Australia. Cremation appears to have been a popular practice throughout much of the known world, from Mixtecs in Mesoamerica to log pyres in India to Stonehenge in England. The rise of Christianity during the Roman Empire, however, helped to displace cremation in favor of burial in much of the world. By the 19th century, however, a diminished belief in literal resurrection allowed the practice to slowly regain popularity.
- Modern cremation is often performed in a "cremator," an industrial furnace that can reach temperatures of over 1400 to 2100 degrees Fahrenheit. At these temperatures, the vast majority of the human body is vaporized over the course of approximately two hours, by which point, only dry bone fragments should remain. These larger bone fragments are then ground down into a finer, ash-like consistency with a device known as a "cremulator." When all is said and done, the resulting remains usually weigh only 2 to 3% of the cremated individual's original weight. These ashes are then turned over to the family or next of kin in a sealed container, or an urn.
- Human ashes can be disposed of in a myriad of possible ways. Many families scatter the ashes in a way requested by the deceased, although local laws may vary as to the disposal of human remains. An urn of ashes can also be entombed in plots explicitly designed for the purpose, or even interred with special permission in plots that have been previously occupied. Methods of disposal can vary as widely as the deceased. Ashes may be mixed into artificial reefs or paint, get sent into orbit, or even serve as the raw material to manufacture an artificial diamond.
- Mass cremation has sometimes been practiced during times of widespread death, especially after natural disasters or in the wake of epidemic disease. Many religions explicitly state their stance on cremation. While the Hindu religion specifically mandates cremation through open-air pyres, for example, Islam, Baha'i and Orthodox Judaism strictly prohibit it. And while cremation is widely accepted in the Protestant community, it continued to provoke debate in the Roman Catholic Church as late as the 1960s, where it conflicted with the idea of resurrection.
- The cremation process is generally viewed as gentler on the environment than burial, since cremation does not require toxic embalming fluids or large tracts of land. Many countries, such as Japan, have little to no space remaining in their cemeteries. But wide-scale cremation, as in India, has also led to significant environmental damage. Collecting the wood for pyres has prompted widespread deforestation, and the ashes are later scattered in local rivers. In addition, crematories can generate noxious emissions from the incineration of heavy metals in the body.
