A Houston-based company has announced plans to rocket the ashes of Star Trek’s James “Scotty” Doohan into space. Less than 10 grams of Doohan’s ashes will be sent into the great beyond—the vessel will include bits of about 100 other people, including former astronaut Gordon Cooper. How much ash is produced when a body is cremated?
About 5 pounds for an adult. The weight can vary from 3 pounds all the way up to 10, depending on the size and density of the deceased’s bones. Organ tissue, fat, and fluids burn away during cremation, leaving only bone behind when the incineration’s completed.
In general, the taller the person, the more bone or “ash” is left. Men generally produce more ash than women do because their bones are denser. And young people usually have greater bone density than the elderly because of age-related bone loss. Animals work the same way—a fine-boned bird will produce less ash than a dog of similar size.
During cremation, a corpse is burned at around 1,700 degrees for two to four hours—the fleshier the person, the longer it takes to cremate the body. After incineration, the remaining bone fragments are ground up into a substance with the consistency of powder. (The powder might include larger bits of bone that didn’t get ground down completely.) The final remnants are known as ashes or cremains.
Bodies are sometimes cremated inside a container, such as a wooden casket used for a viewing. In that case, wood ash and the casket’s latches and handles might get mingled with the remains, adding a negligible amount to the final weight of the cremated remains. (The metal pieces are removed before grinding.)
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Explainer thanks Dave Kues of Chesapeake Crematory and Bev Heckrotte of Going Home Cremation Service.