So Shines a Pale Dot in a Vast Expanse

Last week, a Martian character from SyFy’s The Expanse looked out on the ocean of Earth and said “You take it for granted,” while the news filled with changes to government policies on climate change.
 
Cruel coincidence. Though if it is, it feels strangely expected.
 
My love of science fiction predates my love of science. Both are speaking to me this week, as I read Carl Sagan’s Pale Blue Dot, and as I watch the second season of The Expanse, an adaptation of the novels of James S. A. Corey. It strikes me that they share something in their tone. This seems, on the face of it, unlikely; Carl Sagan is an unfailing optimist towards human endeavours in science, and The Expanse, for all its glory, is pushing towards dystopian in its portrayal of Earth. Yet the message that they share, the message that Sagan never stopped preaching, is that Earth is precious. Or to quote The Expanse’s Amos, “You can’t replace Earth.”
 
It seems that this should be otherwise, at least in fiction. With powerful fusion drives, with mirrors that concentrate Jupiter’s light onto its moons, with domes and terraforming on Mars, surely there is some distant day when we will not rely on the Earth? The Expanse says no. Sagan says no. Physics and biology say no. Going to Mars, and even terraforming it, is within our capabilities, but a terraformed Mars is not a substitute for Earth. And even if the planets of our Solar System are possible, the stars are not; the distances in our galaxy are insurmountably vast. The ability to find or build a new home for humanity is so close to impossible that it’s a rounding error.
 
The difficulty of even leaving Earth, never mind replacing it, comes home when I’m teaching the laws of motion to my students. My repeated line is “Physics is not your friend.” As they try to imagine spacecraft that might actually leave the Earth on trips to the Solar System, they are not allowed to skip the details. The incredible challenges of leaving Earth are reinforced even as they try to work around them. Ironically, this is not rocket science. It is basic arithmetic. It does not take long for students in my class to realize that even modest outings into space are extremely difficult. The lesson is not merely Newton’s laws, but the reality that they reinforce: space travel is hard. Earth is all the more precious because of it.
 
That we forget this for even an instance, that we take those oceans for granted, is inexcusable. That governments forget this is borderline criminal. I could expound on the environmental catastrophe inherent in ignoring our tenuous place in the Solar System, but better scientific minds than mine have already done so. What I object to is ignorance, or the stubborn refusal to see facts that is currently masquerading as ignorance. It is immoral for governments to act as if the Earth is expendable – tantamount to burning down a house with the inhabitants still inside. As always, Carl Sagan said it best: “Like it or not, for the moment Earth is where we make our stand.”
 
For the moment. Moments in the span of cosmic time are long – longer than any of us may have. For the moment, this is all we have – a blue dot suspended in the vast expanse.  

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