Bridging the gulf between science-fiction and science fact
Bridging the gulf between science-fiction and science fact
It's a popular refrain nowadays: "Where's the jetpack I was promised? Where are the flying cars? The hoverboards?'
As much as we look in admiration on the "prophetic" works of Jules Verne, H.G. Wells and other nineteenth and early twentieth century science-fiction visionaries, we wag our heads in disappointment and even mockery at more contemporary scribes, who promised us an amazing future with unbelievable technologies, where space travel would be as commonplace as a drive to the corner store. Oft times, our world more closely resembles the dystopian imaginings of Aldous Huxley, George Orwell, and E.M. Forster, men who are considered science-fiction writers only by virtue of the fact that they wrote of a possible (and sadly all too likely) future, and not because their stories were rooted in hard science. Science, and by extension, hard science-fiction, seems to have failed to give us that gleaming Utopian future we were promised.
Space travel seems especially to be an area where the reality has come up short. It took just 66 years for us to go from Kitty Hawk to the moon, but in the forty-odd years since, we haven't done much with that accomplishment. Instead of the permanent moon base envisioned by Arthur C. Clarke in the 1968 novel/movie 2001: A Space Odyssey, we have retreated back to low earth orbit. And Mars? Oh, we talk about it once in a while and send out robots to explore our nearest neighbor, but setting foot on the red planet seems less and less likely with each passing year.
One reason for our disappointment is that we focused a little too much on the fiction part of science-fiction We've always thought of space travel in heroic terms--brave explorers, venturing into the final frontier. Space is just a big empty void, a sea of mostly nothing between the planets and stars. Crossing it is just a function of fuel and staving off the endless boredom...at least until we can crack the secret of faster-than-light travel. What's so hard about that?
Unfortunately, the reality is that traveling through space introduces a host of challenges that can be tough for our earth-based sensibilities to grasp.
We know for example that prolonged periods of weightlessness cause muscle wasting and bone density loss. Floating in the free fall of space is just not the same as floating in a swimming pool. Constant acceleration, or perhaps a spinning centrifuge design might offset these problems, but those solutions are much easier said than done.
The biggest danger in space though is cosmic radiation, and new data gathered during the interplanetary voyage of the Mars rover Curiosity have revealed the extent of that danger to future astronauts who hope to someday plant our flag on red soil.
Here on earth, we are largely protected from cosmic rays by our atmosphere and magnetic field; the most dangerous type of radiation from space that we must contend with is ultraviolet light, which can cause sunburn and skin cancer with prolonged exposure. In space, there is considerably less protection. An astronaut aboard the International Space Station for six months receives a dose of radiation that is about ten times higher than what the average person on earth receives. Astronauts on a mission to Mars--the shortest possible journey would last the same six month period--would receive about five times as much radiation as those on the ISS or nearly fifty times what we would be getting back here on earth, significantly increasing their risk of cancer. Double those numbers if you include the return trip.
You may be asking, why not just raise shields?
Radiation is a tricky subject. Visible light is a type of electromagnetic radiation, with light "particles"--photons--traveling in wave patterns of different frequencies. We can feel these rays striking our skin in the form of thermal energy--heat--but visible light does not go very deep into solid matter. If you've ever stuck a flashlight in your mouth and observed how your cheeks get red, you've seen this effect at work; most of the wavelengths of light are absorbed by your skin, and only a faint red glow can be observed. Increasing the frequency or energy of photons will result in deeper penetration into matter, and can have ionizing effects--essentially, knocking electrons loose from atoms. Ionizing radiation can lead to the kind of cellular mutations that cause cancer. Some types of EM radiation, such as X-rays, can only be stopped with a shield of dense metal, such as lead. Exposure to X-rays or microwaves (yes, the kind you use to pop popcorn and heat up water for a cup of tea) can cause cellular damage, but limiting exposure can greatly reduce the risk of cancer-causing mutations.
Cosmic rays however are a different story. In the simplest possible terms, cosmic rays are ions--material particles with an electrical charge--released by exploding stars throughout the universe. Cosmic ray particles, unlike photons, have mass. It's a bit mind-boggling to think about how much energy is involved in transporting these particles across thousands of light-years, but maybe this will help.
Imagine a grain of sand, a mere irritant if it gets in your eye, or if several of them collect in your shoe, but driven by the desert wind, those grains of sand can burrow into your skin and scour the paint off your car. Fortunately, we can cover up and protect ourselves. It's the energy that makes the difference; the more energy the particle contains, the more damage it can do. If ultraviolet light is like the grit in a sandstorm, then X-rays might be compared to the output of a commercial paint-stripping sandblaster.
Now, imagine replacing the sand with pebbles. It takes more energy to propel a pebble than it does a grain of sand, but the amount of damage is considerably greater because the pebble is more massive than grains of sand. Accelerate that pebble to ballistic velocities and you've got a bullet. That's the difference between EM radiation and cosmic rays.
As unbelievable as it sounds, there is no practical way to shield a spacecraft from cosmic rays. These particles have so much energy that walls of concrete and lead don't even slow them down. We are relatively safe here on earth because our atmosphere absorbs most, but not all, incoming cosmic ray particles, and that protection decreases with altitude. The flight crews of commercial airliners will receive more exposure than people who spend their lives at sea level, and the health risk--the radiation exposure from a cross-continental flight is about half that of a chest X-ray--while relatively minimal cannot be ignored. Astronauts embarking on a mission to Mars would be playing a game of Russian roulette with cancer, and that's just one of the many thorny scientific realities that have confounded our fiction-inspired dreams of colonizing the rest of the solar system.
The problem of cosmic radiation is by no means insurmountable, but it well illustrates how science fiction can raise our expectations beyond what is reasonable, and in so doing, intensify our disappointment if--and let me stress this--if we don't apply our not-inconsiderable intellectual resources to the matter of finding a solution. Science-fiction writers are not prophets of science, predicting what our future will be, but rather are more like cheerleaders, telling us a future we can have if we just work toward it. No matter how much team spirit those cheerleaders can rouse, the game can only be won by the players on the field.
It's often been said that the average person has more computing power available to them in their smart phone than NASA had during the first moon mission. Where we are consistently coming up short is in science and mathematics education. All of that technological power will not advance us toward loftier goals unless we have trained and talented people using it to solve the problems that keep science-fiction from becoming science fact.
Sean Ellis is the author of several thriller and adventure novels. He is a veteran of Operation Enduring Freedom, and has a Bachelor of Science degree in Natural Resources Policy from Oregon State University. Sean is also a member of the International Thriller Writers organization. He currently resides in Arizona, where he divides his time between writing, adventure sports, and trying to figure out how to save the world.