The possibility of deflecting an incoming asteroid became more problematic in early July. That’s when David Polishook and Noah Brosch (both of Tel Aviv University) presented evidence that the number of binary asteroids near the Earth might be much higher than originally thought. Binaries might, in fact, comprise more than fifty percent of all NEAs. Now we’re talking about moving two objects instead of just one, an indication that asteroid-nudging is more tricky than we thought.
The paper “Many binaries among NEAs,” available here, was presented at NASA’s Near-Earth Object Detection, Characterization, and Threat Mitigation workhop in Colorado. It’s a reminder that the environment incessantly nudges technological civilizations to extend their capabilities. Jose Garcia recently commented here on a story about the New Worlds Imager ‘starshade’ concept, noting that experience with starshades could come in handy in future attempts to mitigate the effects of global warming by covering up parts of our own star.
Far fetched? In today’s terms, sure, but thinking ahead is what this is all about, and who knows what a technological race might accomplish with starshade technology in an attempt to keep its home world habitable. We seem to live in a universe that pushes us toward Kardashev Type II status, defined as a civilization that can exploit all the energy of its star. Could adjusting our Sun’s effects upon the Earth be a faint harbinger of such an outcome? I suspect evolution from Type I (harnessing the power of an entire planet) and on to Type II is all but essential for any species to survive over genuinely long time frames, its home planet challenged by all the menaces of solar system living.
On the starshade front, I notice that BBC has now picked up the Webster Cash story, drawing on an interview with Cash and the paper he recently wrote in Nature. Here Cash reiterates his belief that the fastest way to accomplish a planet-finder mission with this technology is to follow the James Webb Space Telescope, launching several months after it and using it to collect starshade observational data.
One problem is noted by Timothy Naylor (Exeter University), who points out the need for keeping shade and telescope in precise alignment. It’s tricky business, especially given the time frames involved. “If you are trying to collect the light from a planet then you are going to have to stare at it for a relatively long period of time to do anything really useful,” says Naylor, a good point and one we’ll address in a future article.
