A team of Caltech astronomers created what could be the most accurate computer simulation of our galaxy's birth. See, according to computations for older simulations, our galaxy should be surrounded by thousands of dwarf galaxies. In reality, though, there are only around 30 dwarf galaxies nearby. Astronomers thought their computations were incorrect, because we still don't understand the true nature of dark matter that permeates every corner of the universe. However, the Caltech team found out that it's not dark matter that's the problem. Their computations were able to achieve the current state of our galaxy simply by incorporating the effects of supernovae.