Dottie understood this, so she let him work. Dottie needed serious Net access even worse than Van did. Astrophysicists were the world’s heaviest users of scientific broadband. When an astrophysicist wanted to "send a file," that meant some colossal mountain of data that would simulate the entire atmosphere of the gas-giant Jupiter. Astronomers had such ferocious need for bandwidth that they were up for any scheme that might get it for them, no matter how far-fetched. They even hooked millions of PCs together, in giant volunteer networks, that combed the galaxy around the clock for alien radio signals.