THE FIRST STARS AND BLACK
There are two branches of theoretical research in cosmology. One considers the global properties of the Universe and the physical principles that govern it. As more data come in, our knowledge of the initial conditions as well as the underlying cosmological parameters gets refined with higher and higher precision. The second branch focuses on the formation of observable (luminous) objects out of the cosmic gas, including the stars and black holes in galaxies. Here, as more data come in, the models get more complex and the modelers understand more clearly why their previous analysis oversimplified the underlying processes. Theorists who work in the first branch run the risk of needing to switch fields in the future once the precision of the data becomes so good that there will be no point in further refinements (as happened in particle physics after its standard model was established in the 1970s). Theorists in the second branch run the risk of spending their career on a problem that will never get elegantly resolved.