On Sat, Jan 11, 2014 at 4:20 PM, David L Babcock <[email protected]> wrote:
A continent-melting crash requires that more than a continent-melting > supply of fuel has been applied to/used by the craft. > You make an excellent point. But we should not become too complacent in feeling safe that no mis-aimed spaceship will obliterate us. If they have a (hypothetical) cold-fusion-powered thruster, the amount of energy they can draw upon is quite high, provided they have enough fuel (whatever that is). Assuming they don't use a trick with a wormhole or something similar, would the main gating factor not be the maximum thrust/power and the distance from us at which they set out? Also, they could use Dave's slingshot trick to get quite a boost, perhaps even a continent obliterating one. Drivers licenses will be especially important for interstellar travel. Eric
