David Bowie and Elton John sang of it like it is right around the corner, but the truth is that it is a long way to Mars – a spacecraft flying at 24,600 mph (39,600 kph) would need about seven months to travel the 300 million miles (480 million km) expanse of space between Earth and the Red Planet. (480 million kilometers). Assuming there are humans on board, that ship would need to carry enough food for the trip or a Star Trek machine that makes it from thin air. One solution to this problem is suspended animation – the slowing or stopping of all biological functions for most of the trip. Science fiction has conditioned us to think of suspended animation as an artificial state where humans are locked inside a container which maintains minimal health and safety requirements, along with conducting the reanimation process. We don’t have that technology yet, but three new studies suggest we may not need it – humans have the innate ability to enter a hibernation state just like bears and other mammals. In one, newly discovered fossils show that some prehistoric humans in frigid climates survived by entering metabolic states for several months where they did nothing but lie still while living on stored body fat – and modern humans still have the gene that allows this just waiting to be reanimated. Another study has found how to induce a state of artificial hibernation in non-human primates. And a third is researching the ability of Tibetan monks to enter a state of meditative hibernation. Let’s see which one works best and can be ready the fastest.
“Humans, like other mammals, may already have the biological “machinery” to hibernate, but we need to figure out how to activate, regulate and coordinate all the necessary processes.”
Dr. Marina Blanco, a research scientist at Duke University in the U.S., who has studied hibernation in dwarf lemurs, explains in The Daily Mail how human hibernation is an ability we already have hidden in our genetic makeup. Some mammals like brown bears, lemurs and hedgehogs are known hibernators – they intentionally slow down their metabolic processes to almost nothing in order to survive months of cold weather and scare food supplies. While the process of entering hibernation is well understood, the process of leaving hibernation is not – attempts to simulate it are stymied by the shock that bodily organs and tissues suffer when blood flow is reestablished. Reducing body temperature helps – this is the process used during long surgeries – but it can’t be maintained for the months needed for a space trip.
Unless you live in the “Chasm of the Bones”. Sima de los Huesos is a 430,000-year-old cave in the Cueva Mayor in the Sierra de Atapuerca mountains of Spain which is considered to be the oldest known cemetery in history – containing about two thousand bones belonging to at least 32 different individuals, making it the largest collection of human fossils from the Middle Pleistocene era. Some of these fossils are so well-preserved, ancient DNA has been extracted from them. A paper published in the journal L’Anthropologies reveals that some of these fossils show that bone growth was slowed or stopped for several months of each year, implying that early humans entered “metabolic states that helped them survive for long periods of time in frigid conditions with limited supplies of food and enough stores of body fat.” However, this was not hibernation but a state of torpor – an involuntary state of energy conservation seen in mice, hamsters, birds and other creatures where body temperature, breathing rate, heart rate and metabolic rate drop to low levels. Can humans enter states of topor today prior to long space flights?
“It seems to be a widespread and ancient behaviour, and there are primates that do it to this day.”
Dwarf lemurs are the only primates that enter topor states naturally, but Dr Michael Ambler, a clinical lecturer at Bristol University who researches hibernation in animals, has induced it in rats which, unlike mice, don’t normally experience it. Ambler believes that the bones in Sima de los Huesos Cave show humans are capable of topor and that state could not only allow long trips with little food storages, but also protect them from space radiation.
“It seems that if your cells aren’t very active, then the DNA is more tightly coiled, making it less prone to be broken apart and degraded.”
While that group works on reactivation the topor gene in humans, researchers in China have taken a different approach – long-term hypothermia. A research team led by Dr. Wang Hong and Dr. Dai Ji from the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences report in the journal “The Innovation” of the first reliable hypothermia in nonhuman primates caused by activating a group of hypothalamic neurons. Hypothermia is the formal name for lowering body temperature and greatly reducing metabolic activity – the technique used in hearth transplants and other long-term surgeries. It is also the accidentally state many people have survived after falling through the ice of a frozen lake or being exposed to extreme temperatures for what should be long past fatal times and yet surviving. The Chinese research team attempted to induce non-fatal hypothermia crab-eating macaques (Macaca fascicularis) by combining chemogenetic manipulation, functional magnetic resonance imaging (fMRI) scanning and behavioral analysis to maintain the state within a narrow set of physiological and biochemical parameters.
They artificially reduced the body temperatures of the primates by locally infecting excitatory neurons in the POA of the hypothalamus in the monkey brain with DREADD-encoding viruses (“DREADD” refers to designer receptors exclusively activated by designer drugs.) They were pleased to see a decrease in core body temperature, antagonizing external heating, thus proving that excitatory neurons in the POA play a critical role in thermoregulation in the primate brain. Dr. Wang says this is true progress towards flying humans to Mars in a frozen hibernation state.
“With the growing passion for human spaceflight, this hypothermic monkey model is a milestone on the long path toward artificial hibernation.”
Meanwhile, in Russia …
Tibetan Review reports on recent experiments on replicating the deep meditation practices of Tibetan Buddhist monks as a way to induce a hibernation state for interplanetary travel. This would be the least expensive mode since it involves no storage pods or refrigeration – just the human mind. Representatives of Moscow State University are studying the electrical activity of the monks’ brains during meditation, and have noted that they are able to achieve sensory deprivation and deep concentration while slowing down their metabolisms. Experts from the Russian Federation are working to select the best of several effective techniques and learn how to train space travelers to achieve the monk-like states of deep meditation. While not as long-term as the other hibernation or topor techniques, it may be used in conjunction with them to reduce the stress on the human body during, exiting and recovering from the states of hibernation needed to reach Mars.
Would you prefer to travel in a state of frozen hibernation or wait until faster modes of transportation are available? Both involve tremendous risks, and neither is close to happening. Remember that when billionaires talk about their plans to send thousands of humans to colonize Mars.