What If We Can Never Leave Earth?
Only 24 people in the entire history of humanity have travelled beyond low Earth orbit and beyond the protective blanket of our planet’s magnetic field. The 24 men accomplished this feat decades ago, as astronauts in NASA’s Apollo program. They left our planet in peak physical health, and at the time seemed to have returned none the worse for wear.
As these former astronauts reach old age, their health continues to be studied. Admittedly, the sample size is rather small to draw serious conclusions (7 of the 24 are deceased), but recent research suggests a troubling trend.
An article just published in Scientific Reports suggests that Apollo astronauts are dying from cardiovascular disease at a rate 4-5 times higher than other astronauts because the type of cosmic and solar radiation experienced outside the magnetosphere causes specific damage to the types of cells that form our blood vessels. The researchers then demonstrated how this damage occurs in mice.
Forty-three percent of now-deceased Apollo astronauts who flew to the moon died from cardiovascular disease. Compare that to just 11% of astronauts who flew in low earth orbit, and 27% in the similar U.S. population (As you can see, astronauts train to be much healthier than the rest of us, which makes this result all the more startling.).
Finally, consider that these astronauts only received a few days of this radiation dosage. Space excursions lasting weeks, months, or years might just be suicidal.
Then there are the psychological effects. The Apollo astronauts reported seeing flashes of light, an effect of cosmic rays interacting with the retina of the eye. This was just a preview of the possibly-permanent cognitive degeneration that would occur on a trip to Mars, which would include forgetfulness, confusion, and slowing response times.
Imagine your neurons being shredded by a machine-gun spray of high-speed particles. That’s basically the state of the universe a few thousand miles beyond earth’s atmosphere.
Can We Shield Astronauts?
According to the Thayer School of Engineering at Dartmouth College, a “massive material shield,” or extra-thick spacecraft hulls, would not work because they are “too massive to be practical and will likely produce showers of secondary radiation that could be more harmful than the GCRs [galactic cosmic rays] themselves.”
Therefore, much of the current research explores the possibility of generating a magnetic shield like the Earth’s magnetosphere. However, the engineering challenge is to produce a field “strong enough to deflect GCR particles but weak enough to not harm astronauts.”
Maybe engineering breakthroughs will occur on magnetic shielding. It is also possible we’ve reached the practical limit. As one NASA website says, “Currently, these [electrical or magnetic] fields would take a prohibitive amount of power and structural material to create on a large scale, so more work is needed for them to be feasible.”
To summarize: Maybe our engineers can figure out a practical way to deflect protons, neutrons, ions, and other particles, some of which are accelerated to near the speed of light, but maybe they never will. If a solution is not found, humanity will never be physically able to visit another planet.
Implications of Being Stuck Here
It’s a depressing thought, but a few decades from now, humanity may be done with space exploration.
Without a solution to the radiation problem, space could be considered a place solely for unmanned probes, satellites, and other robots. The human spaceflights of the past would be considered impractical stunts. Our fantasies about spaceships and the exploration of other planets might be too hard for better-informed people to fathom, much like it is hard for us to imagine the physics-defying transportation devices imagined in the fiction of long ago.
As disappointing as this result would be, it might at least focus our attention in productive ways.
Earth’s environment seems much more important if there will never be lifeboats in the future. Similarly, we might begin to think of technology beyond the narrow paradigms of electronics and transportation. We might begin to think of new ways – technologies – to get humans to cooperate instead of fighting wars and committing crimes.
Being stuck on Earth might force us to face certain challenges we’ve swept under the rug. What if we lost our escapist attitudes and faith in the inevitability of humanity’s progress towards a Star Trek future, only to gain a new, more practically valuable, vision?
Maybe our grandchildren’s science fiction will be about a future world where racism, superstition, groupthink, cognitive biases, cynicism and other plagues of the human mind have been eradicated, or where breakthroughs in medicine or education produce humans with double their grandparents’ intelligence?
What if children someday dreamed of tackling the meta-problems, rather than flying a space ship with lasers that hurt other people while making “pew pew” sounds in the vacuum of space?
An Earth-bound future could still be quite interesting after all.