Allegretto is a tempo marking, which means fairly fast, but not as fast as allegro. It can also be a title of a movement or a piece, since Classical movements are often referred to by their tempo markings.
Allegretto from Beethoven's Symphony No.7. Is what was played in the trailer.
Around 115bpm
In music, "allegretto" is a tempo marking that indicates a moderately fast pace, typically faster than "andante" but slower than "allegro." While there are no specific notes associated with allegretto, it is often used to describe a lively and cheerful character in compositions. The actual notes played depend on the piece of music being performed, as allegretto simply refers to the speed rather than specific pitches or melodies.
The music is actually the second movement Allegretto from Beethoven's Symphony No. 7 in A Major.
Check IMSLP.org.
It is a classical music!!
The background music for Cosmos Episode 13 "Who Speaks for Earth?" at around 9 minutes is the Allegretto Movement from Beethoven's 7th Symphony. Here it is: http://www.youtube.com/watch?v=LdfNTO_o-3k GS
Classical Music
There are several musical tempos that can be considered "fairly quick" such as allegro, allegretto, or vivace.
In a quick, lively tempo, usually faster than allegretto but slower than presto.
Check IMSLP.org.
Classical music didn't come from the United States. Classical music was formulated in Europe.