Unthinkable to build a black-hole starship? Never

IF WE are ever going to build a spacecraft capable of reaching the stars, we may have to harness the power of black holes or dark matter (see “Dark matter rockets and black hole starships”). Even contemplating such impossible-sounding craft may sound like a waste of time and money, but it is not. Thinking “the impossible” has frequently opened up rich and unexpected areas of science. X-rays, nuclear power and spaceflight itself were all once considered impossible. They have all changed our world. Why shouldn’t black-hole power do the same?