Which is why Stross ended with: > Anyway, the point I'd like you to take away from this is that while it's really hard to say "sending an interstellar probe is

Which is why Stross ended with: > Anyway, the point I'd like you to take away from this is that while it's really hard to say "sending an interstellar probe is absolutely impossible", the smart money says that it's extremely difficult to do it using any technology currently existing or in development. We'd need a whole raft of breathroughs, including radiation shielding techniques to kick the interstellar medium out of the way of the probe as well as some sort of beam propulsion system and then some way of getting data back home across interstellar distances ... You wrote: "Einstein said that nuclear fission was impossible". Do you have a reference for that? The closest account I know is described at http://www.doug-long.com/einstein.htm http://www.doug-long.com/einstein.htm : > Among those concerned were physicists Leo Szilard and Eugene Wigner. But Szilard and Wigner had no influence with those in power. So in July 1939 they explained the problem to someone who did: Albert Einstein. According to Szilard, Einstein said the possibility of a chain reaction "never occurred to me", altho Einstein was quick to understand the concept (Clark, pg. 669+; Spencer Weart & Gertrud Weiss Szilard, eds., "Leo Szilard: His Version of the Facts", pg. 83). but that wasn't about nuclear fission per se but of a chain reaction. Also, how was Fermi involved? Fission was "was discovered on December 17, 1938 by German Otto Hahn and his assistant Fritz Strassmann, and explained theoretically in January 1939 by Lise Meitner and her nephew Otto Robert Frisch." - https://en.wikipedia.org/wiki/Nuclear_fission https://en.wikipedia.org/wiki/Nuclear_fission .