A combination of data-churning telescopes and proprietary algorithms has led to a slate of opaque research that has some astronomers concerned. When astronomer Kai Polsterer’s laptop was stolen, the thieves made off with more than hardware. The laptop contained Polsterer’s only copy of a collection of thousands of stars and galaxies, a sample that a computer algorithm had randomly selected from a data set consisting of millions of celestial objects. Because Polsterer could not re-create what the algorithm had done, he could not exactly reproduce his data set for a work-in-progress journal article. And without a data set, nobody could...