mindless

Time is a hugely complex subject. The Time of Relativity theory is undoubtedly akin to a negative spacial dimension (cf Weyl's analysis), recent experiments on quantum interference through time reinforce this view (see Lindner et al 2005). The time of Change is highly correlated with the dimensional time of Relativity but may not be exactly the same, for instance according to Multiverse theories two differing outcomes may coexist and be derived at the same location in a common spacetime. The time of causation is also problematical, as Reichenbach pointed out, the spherical symmetry of spacetime means that although chains of cause and effect can be pursued into the future it is difficult to pursue them into the past - for instance try to calculate the inverse of a spreading ripple from a needle dipped into a pond so that the disturbance at the edge of the pond ends up as a dip in the water surface at the exact place that the needle entered. Even more complex, try to think of something that exists for no time at all. Can an object have no temporal parts? Lindner, F., Schaetzel, F.G., Walther, H., Baltuska, A., Goulielmakis, E., Krausz, F., Milosevic, D.B., Bauer, D., Becker, W., and Paulus, G.G.. (2005) Attosecond double-slit experiment. Phys.Rev.Lett. 95,040401 (2005)

The NOVA would not work as a result of the casing (as pointed out by previous posters). Using nuclear bombs to compress a large amount of plutonium into a bomb might work (chemical explosives are used at present). The best way to make a lethal nuclear bomb is to enclose it in a thick cobalt casing so that it creates vast amounts of lethal cobalt isotopes. This was called the "cobalt bomb" and I think it is banned by convention - it would wipe us all out.

In my experience as a scientist once an hypothesis has more than one speculative connection your chances of being wrong rise horrendously. If I have an hypothesis that says "suppose A gives rise to B according to my hypothesis" I have a reasonable chance of a successful theory, if I then add another "suppose B gives rise to C..." my chances of being right are, for various reasons, much worse than the product of the two probabilities. The main reason that chains of hypotheses are not worth anything is that the result of any hypothesis in the chain is always ill defined. A does not give rise to B, it gives rise to something that is almost like B, the next step in the chain is then a hypothesis that "something almost like B gives rise to C"... So what are the chances of cosmological speculations involving multiple steps, that cannot by definition ever be tested, being right? That said, four dimensional pseudo-Riemannian geometry is worth studying.