Comprehend the mind colorcross3/30/2023 ![]() Initially, there was great skepticism that the so-called ‘spiral nebulae’ seen in deep photographs of the sky were in fact ‘island universes’ – structures as large as the Milky Way, but at much larger distances still. When astronomers made the first definitive measurements of the scale of our Galaxy a century ago, they were overwhelmed by the size of the Universe they had mapped. Or they invoke warp drives, wormholes or other as-yet undiscovered phenomena. Science-fiction writers use a variety of tricks to span these interstellar distances: putting their passengers into states of suspended animation during the long voyages, or travelling close to the speed of light (to take advantage of the time dilation predicted in Albert Einstein’s theory of special relativity). Yet getting to these planets is another matter entirely: Voyager 1 would arrive at Proxima Centauri in 75,000 years if it were travelling in the right direction – which it isn’t. The Vogons in Douglas Adams’s The Hitchhiker’s Guide to the Galaxy (1979) are shocked that humans have not travelled to the Proxima Centauri system to see the Earth’s demolition notice the joke is just how impossibly large the distance is. ![]() You would have to line up 30 million Suns to span the gap between the Sun and Proxima Centauri. ![]() The nearest, Proxima Centauri, is about 270,000 AU, or 4.25 light years away. The spacecraft Voyager 1, for example, launched in 1977 and, travelling at 11 miles per second, is now 137 AU from the Sun.īut the stars are far more distant than this. This distance, the radius of the Earth’s orbit around the Sun, is a fundamental measure in astronomy the Astronomical Unit, or AU. And the distance between the Earth and the Sun is about 100 times larger than that, close to 100 million miles. The Sun is much bigger its diameter is just over 100 times Earth’s. A non-stop flight from Dubai to San Francisco covers a distance of about 8,000 miles – roughly equal to the diameter of the Earth. We say that the observable Universe extends for tens of billions of light years, but the only way to really comprehend this, as humans, is to break matters down into a series of steps, starting with our visceral understanding of the size of the Earth. Just how large the Universe actually is never fails to boggle the mind. The real challenge is to tie the story to human emotions, and human sizes and timescales, while still capturing the enormous scales of the Universe itself. In practice, this means that most science fiction takes place in relatively relatable settings, on a planet or spacecraft. This is what we respond to it is what we can best understand. No matter how exotic the locale or how unusual the scientific concepts, most science fiction ends up being about quintessentially human (or human-like) interactions, problems, foibles and challenges. As an astrophysicist, I am always struck by the fact that even the wildest science-fiction stories tend to be distinctly human in character.
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