What is the definition of a solstice, and when do they happen? Is the winter solstice always the first day of winter? Find out what causes these bi-annual astronomical events, as well as how they bring about the shortest and longest days of the year.
This clip takes us into the universe through a series of steps, with each step being 10x larger than the previous. It illustrates the vastness of the universe and that increasing the field of view by a power of 10 makes a dramatic change in what we see.
This song discusses Tarzan's fascination with the wider human world he has yet to see. During the song, he looks through a telescope and sees the Great Comet of 1882.
Penrose describes his black hole theory, which sparks an idea in Stephen's mind. Stephen reverses Penrose's theory and develops one of his own. Stephen suggests that the universe was born from a black hole exploding. The black hole has such strong space-time singularity that nothing can escape from it, even light. The black hole is triggered by the collapse of a star.