danny wrote:Platypus6 posts got me thinking, can a spaceship be made that is impervious to damage from the back using rakes and destruction reactions?
What speed spaceship? For anything slower than c/2, the problem is that low-period rakes have big gaps between the gliders, and it's probably always possible to design some kind of custom salvo that flies in through the gaps, maybe suppressing a key glider here and there along the way if necessary, and strikes some vital spot on the spaceship.
Conversely, high-period rakes are made of mostly-not-empty-space, and we know that information can travel faster than c/2 through not-empty-space. So it would be hard to completely rule out some kind of virus or other chain reaction that travels back through the low-period glider stream and attacks the source rakes, even for a c/2 spaceship.
Really by some definitions, c/2 orthogonal spaceships in general _are_ impervious to damage from the back, in that there's no reasonable fleet of spaceships that you can send from, say, ten cells or more behind an LWSS, that can possibly catch it and damage it.
-- I would say that something closer to two blank cells are enough of a safety gap after a c/2 spaceship, but maybe somebody would then come up with a degenerate "fleet" of spaceships that collide with each other to make some kind of wave front that travels faster than c/2:
Code: Select all
x = 80, y = 23, rule = B3/S23
39b3o$39bo2bo$39bo$39bo$40bobo18$80o!
But lightspeed limitations prevent this kind of attack from being assembled behind a c/2 ship, unless it's already there at T=0. You won't see this kind of thing happening much with old spaceships in old Life universes.
If you have a lightspeed wire handy off to the side somewhere, well, that's another story, but the attack will no longer be "from the back".
