Saturday, 8 June 2013

10:50 – Frances is visiting Dutch today, so Barbara and I are taking the day off to build science kits. She’s out in the den now, watching Private Practice on Netflix streaming while she tapes up bundles of wood splints. When I ordered 10 boxes of 500 splints, I figured that’d last us a long time. Now, as it turns out, it may not last out this year.

Among other things, we’re putting together 57 small parts bags for the chemistry kits. We’d planned to do 60, but as it turns out we had only 57 9V batteries in stock. So I need to order a few hundred more of those. And some more wood splints.

Last year at this time, I noticed while working in the unfinished area of the basement how humid it was down there. I thought about buying a dehumidifier then, but never got around to it. Barbara is running some errands this afternoon, so she’s going to stop at Lowes or Home Depot and pick one up. It’s comfortably cool down there, but the humidity must be up around 80% or 90%.

14:24 – The most recent NEO missed us, as we knew it would. Still, this one, an object somewhere between the sizes of a garbage truck and a large house, passed closer than the moon’s orbit. If you consider that earth’s diameter is about 8,000 miles and the moon’s orbital diameter is about 480,000 miles, then if the moon’s orbit is the outer ring and earth the bulls-eye, that makes the diameter of the bulls-eye about 1.67% that of the entire target and the area something like 0.03%. Considering the object to be a point, that means that if you know only that a large object is going to pass inside the moon’s orbit, there’s still only a tiny probability that it will strike earth, something like 3 in 10,000. Still, given the disturbing frequency of these NEOs, we should be doing a lot more to track them and to devise and implement planetary defenses. As things stand, an object large enough to wipe out civilization may not be detected until a few weeks before impact, too late to do anything but have the party to end all parties, literally.

The farther out an object can be detected, the less force must be applied to it to make it miss the planet. All that needs to be done is to change the velocity–speed, direction, or both–slightly to cause the object to miss. How the velocity changes–faster, slower, up/down, left/right–doesn’t matter. Any change is effective, as long as it’s great enough that the orbit of the object no longer intersects our own orbit when we’re at the same point the object would otherwise have been. A high-power laser impinging on such an object may alter its velocity (orbit) in one or both of two ways. First, if the object is distant enough and the laser is powerful enough, light pressure alone can be sufficient. That works even on metallic objects that don’t ablate significantly. Second, on objects that contain frozen gases, the impinging laser causes outgassing, thereby altering the orbit.

I don’t see how anyone can dispute that it’s long past time that we had some serious space-based planetary-defense assets up there, including an array of nuclear-powered beam weapons. The US government currently wastes trillions of dollars on programs that are simply money down a rathole. It’s time they started investing in real infrastructure, before a planet-killer shows up. We should fund it ourselves if we must, but we should also encourage the rest of the first world to participate, both in funding it and in developing and deploying these planetary assets.