Seth Shostak and I independently hit upon the same topic yesterday, Seth in his regular venue on Space.com and I with a Centauri Dreams post that asked how advances in observational technology might replace actual interstellar travel. Seth’s take is somewhat different from mine, arguing as he does that while we’ll spread through the Solar System, we’ll likely explore the galaxy from home. I, on the other hand, argue that at least a small number of humans will find the means to make the long journey, but perhaps not in ways we often imagine.
Changing How We See Things
I return to the topic to get some of Seth’s observations into play here. For the point of both articles was that we’re making remarkable advances in how we see things, advances that are far more striking than what we’ve managed in propulsion. Thus it took seven decades to go from the V-1 moving at one mile per second to New Horizons, which moves toward Pluto/Charon at ten miles per second. A factor of ten increase in speed in seven decades, this occurred in a time when, as Shostak notes, our camera technology improved by a factor of ten thousand. Then this:
Now you might argue that human exploration is qualitatively different than sending mechanical proxies. We humans want to experience the frontier, not just watch it come up on our computer screen. We want to smell it, feel it, and look around.
OK, but what if we could send back all those sensations with a fidelity as good as being there? That’s becoming more and more practical. The bandwidth of a single human eye, recently measured at the University of Pennsylvania medical school, is roughly 2 megabytes per second. The bandwidth of your ears is much smaller – no more than a few hundred kilobytes per second. Your fingertips and other parts of your anatomy require even less of a data pipe.
In other words, we could send back everything a human could sense with a telemetry channel of, say, 10 megabytes per second. This is roughly the data rate you’ll soon be getting off a blue-ray disk. It’s not trivial to send data at this rate from star to star, but it’s a lot easier than sending ourselves.
Sending even the tiniest probe to a nearby star is a mammoth undertaking, one whose demands we’re nowhere near being able to meet. But it’s also clear that a robotic probe carrying the kind of remote sensing technologies Seth is talking about is a more attainable goal, for the near term, at least, than a crewed mission requiring life support over a period measured in decades if not longer. Throw nanotechnology into the mix and we could be talking about pushing tiny probes with assemblers that can create the needed facilities from asteroid debris upon arrival. Space-based lasers could supply the propulsion.
My hunch is that both outcomes are likely, with human missions obviously emerging later as propulsion technologies give us new options for getting there quicker. I’m also a believer in the Freeman Dyson notion that deep space exploration is not likely to happen as a result of massive government programs, but rather in the fashion of oceanic discovery in the 17th and 18th centuries. Yes, government-sponsored voyages opened up new territories (and let’s not forget Cook in the Pacific, working off Royal Society funding) but doughty bands of colonists driven by their own agendas played a huge role and, in doing so, re-defined the relationship between liberty and frontiers.
A Slow Scenario to Centauri
Here’s a slow scenario, just one of many: A culture capable of building space habitats and terraforming planets moves ever further into the Edgeworth/Kuiper Belt, harvesting resources and gaining expertise. Over a period of thousands of years, it moves deeply into the Oort Cloud and eventually to its outer edges, where the boundaries between the stellar debris of our own Sun and that of the Centauri stars may become indistinct. We find ourselves moving across the interstellar gulf in a series of small steps, an evolutionarily transformed spacefaring race.
It’s just a scenario. Faster is obviously better, but one way or another, a human presence in interstellar space seems as inevitable to me as tomorrow’s sunrise. And think of the reality shows it will provide the stay-at-homes! They’ll be watching people doing what Captain Cook said he would do, going not only “… farther than any man has been before me, but as far as I think it is possible for a man to go.”