It would be the ultimate comeback.

Hundreds of years from now, Britney Spears is thawed from her cryogenic slumber, pumped full of future medicine, and pointed towards the nearest stage to perform a medley of hits in front of a bewildered audience.

While that may read like bad science fiction, it’s not quite as ridiculous as it first sounds.

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Spears is one of several celebrities who have signed on to have their body cryogenically frozen when they shuffle off this mortal coil. And if the latest researcher is too believed, she’ll awaken from her long slumber with her memory and personality intact.

But is that really a good thing?

Frozen in time

A cautionary tale: Austin Powers came back from being cryogenically frozen, but his mojo was missing.

Freezing people who have died with the intention of reviving them at some later date is known as cryonics.

Its official history starts in 1962 when a Michigan physics teacher named Robert Ettinger self-published a book, The Prospect of Immortality, in which he argued that ‘clinical death’ wasn’t the same as actually dying.

He maintained that as long as some basic brain activity remained in the deceased, their body could be frozen until we had the medical science to revive and restore them.

He wasn’t alone in his beliefs, and the early 1960s saw the ‘freeze and wait’ theory emergence from a number of different sources.

The first successful attempt to freeze a body was carried out just a few years later, when James Bedford, a 73-year-old psychology professor, was frozen in 1967.

Almost five decades later, he remains in ‘cryonic suspension’.

A PhD in quackery?

Freezing only your head will cost you about $60,000.

Freezing folks until the future catches up with them may sound like quackery, but it isn’t entirely speculative. Certain frogs and other amphibians are known to produce to a substance called cryoprotectant that preserves their organs when lakes freeze over, and enables them to survive until the water thaws.

Cryonics works in a very similar way. It pumps a synthetic version of cryoprotectant into a deceased body, before placing it in a vat of liquid nitrogen for preservation until a future date.

It costs around $200,000 to have your entire body placed on ice. But if you just want your head in a Futurama style vat it’s a much more affordable at $60,000.

It’s a process scientists have been experimenting with for decades, and freezing bodies is something they’re pretty comfortable with these days.

The part where they have to thaw them out and revive them is more troublesome, but recent breakthroughs have nudged it closer to ‘possibly maybe’ territory.

In one notable (and gruesome) study at the University of Pittsburgh, live dogs had their blood replaced with cryoprotectant and were placed in a state of suspended animation for three hours, pronounced clinically dead, and successfully brought back to life.

Please define ‘dead’

Certain amphibians are known to produce to a substance called cryoprotectant that preserves their organs when lakes freeze over, and enables them to survive until the water thaws. Photo: Getty

It’s worth noting that you can’t simply drop a person in a vat of liquid nitrogen and hope for the best.

Before any kind of medical procedure can be undertaken, a person has to be pronounced ‘clinically dead’. That is, their heart has to have stopped beating.

Any attempts to interfere with the body before this could result in murder and/or assisted euthanasia charges.

Because the official definition of dead is so arbitrary in these cases, the process raises all kinds of ethical and theological questions. Notably, if a person is stopped from dying, are they also prevented from moving on to whatever afterlife there is or isn’t? Will they find themselves in a strange purgatory? Do mostly dead (but not quite) people dream during their frozen sleep?

And then there are the more mundane issues. Like who pays for the upkeep of the body if several generations from now the funds are depleted? Or the company preserving the bodies goes bankrupt?

Also, what do you do with someone after you’ve bought them back to life? Thawing out a body is one thing. Raising the dead is quite another.

Onwards and upwards

Despite the scientific uncertainties and ethical questions associated with cryonics, 270 people have undergone the procedure since the 1960s. And according to the Alcor Life Extension Foundation, business is booming, with both celebrities like Britney Spears and the general public expressing interest.

Aaron Drake, the Medical Response Director at Alcor, noted that today’s generation “is more accustomed to seeing changes in technology”.

“They feel this is kind of an inevitable thing,” he said.

Until then, it’s still wishful thinking, and the plight of two year Matheryn Noavaratpong – who died from brain cancer and became the youngest person cryogenically frozen – summons up that sentiment. Speaking about the process, her parent’s, both doctors in their own right, described her as still alive, “although we have been separated.”

But not everyone is so optimistic. As American science writer Michael Shermer points out, cryonics “is too much like religion: it promises everything, delivers nothing (but hope), and is based almost entirely on faith in the future.

“It is not impossible for cryonics to succeed; it is just exceptionally unlikely.”