I was the kind of student who gave teachers a headache. I was always asking questions. Too many questions. Smart questions. Dumb questions. Annoying questions. Even questions that my teachers clearly figured should not be asked.
To their credit, they did their best. But privately, they probably considered me to be a major you-know-what in the you-know-where.
The day I locked horns with my physics teacher about the possibility of travelling faster than the speed of light is a case in point.
This question was important to me. If faster-than-light travel was truly impossible, that would make any kind of contact with extra-terrestrial intelligence a virtual impossibility.
And I really wanted to meet a Vulcan.
So I demanded to know WHY supraluminal travel was impossible.
He attempted to explain why special relativity establishes c as the ultimate speed limit of the universe. I countered with a list of inventors who did not let the fact that their ideas were considered “impossible” stop them from developing their inventions. He tried to explain the difference between a theoretical impossibility and an engineering challenge. I pointed out the way that new theories can re-write the worldview of old theories. He told me I was missing the point of Einstein’s theory. I asked him why Einstein’s word should be considered the “last word.”
That was when he told me the discussion was over.
In retrospect, I cannot blame him for that. After all, he had a lesson plan to work through, and he couldn’t afford to spend the entire class arguing with me about the speed of light. But I thought he was wrong then, and I still think he was wrong now.
He wasn’t wrong about relativity. But I believe he was wrong in treating Einstein’s work as the final word on the subject. Our knowledge of the universe is incomplete; we have no way to know what kind of discoveries (both theoretical and experimental) might be made in the next decade — never mind the next century. And if there is one thing to be learned from the history of science, it is that no scientist, no matter how brilliant, can hope to have the “last word” in his — or her — discipline.
And as I discovered in university, real scientists understand this only too well.
Some things probably are impossible, in the literal sense of the word. But many are merely “impossible for now”, or “impossible, given our current understanding of physics.” Even fifty years ago, such common technologies as wifi and bluetooth (to say nothing of more esoteric advances like nanotechnology or quantum teleportation) would have been considered “impossible”.
In the 1950s, before Yuri Gagarin’s historic trip into space, a manned moon landing was widely believed to be pure science fiction. But Gagarin’s inaugural spaceflight in 1961 was quickly followed by Neil Armstrong and the successful Apollo mission eight years later.
Even after Apollo, the idea that humans could survive for extended periods away from Earth was generally considered to be pure fantasy — at least until the International Space Station was launched in 1998. Now, in 2015, an actual extraterrestrial colony on Mars is only eight years in the future (assuming the Mars One project continues on schedule, of course).
And so, in just over 60 years, science fiction becomes scientific reality.
In a world where alleged impossibility is often merely temporary, where many of yesterday’s impossibilities are today’s commonplace tools, I think we have to ask what the word “impossible” really means. Absolute impossibility is, I suspect, a rarity; most of what we consider “impossible” is merely “relative impossibility”, or “impossible for us, right now, given our current level of development.”
And as for the future? It hasn’t been written yet.