One really fascinating subject is Cryogenic Sleep… Cryonics must use advanced cooling systems in order to preserve bodies for cryonic rejuvenation; The thing is, all of us don’t have the technology to really revive people who have been preserved and sited under cryogenic sleep.
The only thing Cryonics can do is preserve the bodies with advanced cooling systems and antifreeze cryoprotectants.
This is basically the process of vitrification. The two of us still of course are not able to revive a body that is frozen or has been vitrified, however the hope is that the cooling systems will preserve the body until all of us really do possess the technology to revive these bodies. There are roughly 200 bodies that have been put under Cryogenic Sleep, I know Walt Disney is one who may have signed up for the program, however that might just be an urban legend. It wouldn’t necessarily be surprising though because he absolutely had the currency to do so and it could be that he wanted to eventually live forever. With the rate of technological advancement, there should soon be a time when all of us are able to repair disfigured cells in the body with nano-medicine. This type of medicine would be able to fix the body on a molecular level. Theoretically, those vitrified bodies that are kept preserved with the advanced cooling systems used by the Cryogenic Sleep process should be able to be revived and then the body should be able to come back to prime health conditions. This is the expectation of the future that all of us will be able to keep the body free from germs and that everybody will be remarkably healthy and live for much longer durations of time, perhaps even become immortal.