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Nat Geo's 'Year Million' Explores Humanity's Future in Space Tonight
"Year Million" airs Monday nights at 9/8c on the National Geographic Channel.
Credit: National Geographic

A million years from now humans might become a spacefaring species. The sixth episode of National Geographic's series "Year Million" looks at what the future of space exploration means for the human species' evolution – and it could be profound.

"You could have a population on other planets that adapts to the rigors of that specific environment," Dawn Kernagis, a research scientist at the Institute for Human and Machine Cognition told

Airing tonight (June 19), the last episode of the National Geographic Channel series "Year Million" investigates spaceflight in the far future, and how human beings might cope either technologically or by re-inventing themselves. [Gallery: Visions of the Future of Human Spaceflight]

Kernagis, who studies the effects of deep diving on human physiology, said in space big issues are pressure changes, radiation, and how humans process oxygen. So in optimizing humans one might want to look at the genes that control these processes.

For example, mammals that dive deep – whales, dolphins, and even seals and otters – all store oxygen in their tissues in a different way from humans. Their cardiovascular systems and even the way their blood clots also are optimized for living at depth. This is especially true of whales. "In a way you could call them surfacers, not divers," Kernagis said. "They spend a lot of their time at depth, and come to the surface for gases."

By studying the way human bodies behave in a watery environment, it's possible to extend that to a spaceborne one, where the problem is not too much pressure but too little. [Photos: Underwater Astronauts Practice Space Exploration on Ocean Floor]

Another danger that humans will have to deal with is radiation. The kinds of solar radiation and particles humans will be exposed to on a long trip to Mars, or a far-future interstellar spacecraft, will not be quite like that near a nuclear power plant or on the surface of Earth. Kernagis said there are genes that appear to offer some people reduced susceptibility to radiation poisoning. There are also ongoing studies of people who are exposed to ionizing radiation in the course of their work, to see what might offer some protection.

Even nutritional intake will probably be open to editing by future engineers. "Some people don't take up vitamin D efficiently, for example," Kernagis said. In space nutritional intake is important because the supplies of food are more limited than on Earth.

And while engineering humans is hard, it might be less hard than trying to deal with the health consequences of space travel, especially as people will be in microgravity (or zero-gravity) environments for months or years.

In fact a huge predictor of other problems is the exposure to zero-g, Kernagis said. "You get bone loss, cardiovascular effects," she said. "Based on what we know our bodies don't respond well to zero gravity."

That likely means some kind of artificial gravity will have to be provided on spaceships making extended journeys. Absent new physics that could probably be done by providing rotating sections to the ship, a la the wheel-shaped space station in "2001: A Space Odyssey" or the rotating asteroids in "The Expanse."

The barrier to building such structures is their size, Kernagis notes, though in the future that may change. Either way, humans will probably require some kind of gravity unless they are colonizing a planet, like Mars.

Exploration is something humans will still likely do. "I think there's something fundamental about it," Kernagis said. "Humans have always sought new lands, pushed themselves." Herself a veteran of underwater exploration missions, "I get see people with that mentality, I get that."

Meanwhile humans will have to find ways to live and work in space for extended periods, and it will likely involve multiple strategies. "There's engineering humans for the environment and engineering the environment for humans," Kernagis said.

Year Million airs tonight on National Geographic Channel at 9/8c (check local listings).

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