Desc: Onde Estão Todos os Alienígenas? Nostalgia Ciência: Directed by Felipe Castanhari. With Pirula, Guilherme Briggs, Felipe Castanhari, Leandro Karnal. Astronomers estimate there are a few billion galaxies in the universe, each with a few million stars. The chance of life on other planets seems quite likely with such large numbers, right? This special Nostalgia Ciência program tells you the main theories of "Where Are All Aliens?" in a fun production, with the participation of experts and lots of content.