Natalia C. Villanueva

Right after the Big Bang, the Universe was a chemical desert — only hydrogen and helium, not a hint of metals. But moments passed (by cosmic standards), and the birth of the first stars — Population III — began.

The Universe is less than a billion years old, yet at its centers already sit black holes with masses of a billion suns. According to the conventional picture, they grew by voraciously devouring matter, but calculations show that 'feeding' must have been almost continuous, while visible quasar flares last only a few million years. So where does all the accreting fuel go?