- The large range (F4 to Bb5 = a perfect 11th - where most melodies span about a perfect octave or less) helps provide an expansive sound appropriate to a space odyssey.
- Similarly, the interval of a perfect fifth (in this case Bb up to F) features prominently at the start of the theme.
- Triplets are often used in heroic music - and Star Wars is no exception. The triplet anacrusis opens the theme, and the second, third, and fourth measures of the theme all employ triplets on beat 1.
- Those triplets just mentioned all have a strong tonal inclination to resolve down (Eb-D-C-down to Bb), but instead resolve up (Eb-D-C-up to Bb). This "defying of tonal gravity" furthers the heroic quality of the melody.
As a sci-fi epic, Star Wars has appropriately adventurous and heroic music - particularly the main theme, which uses several music tricks to help establish that heroic quality.
The use of an ascending perfect fifth and triplets has a strong precedent in Richard Wagner's Ring Cycle, particularly in the third opera, Siegfried, which feature's the leitmotif known as "Siegfried's Theme" very prominently.
In 1978, one year after the release of Star Wars: A New Hope, John Williams scored Superman and wrote a theme that bears strong similarities to the Star Wars Main Theme. Both feature very similar openings, with triplet pick ups on scale degree 5 followed by an ascending perfect fifth from 1 to 5; both employ comparable (though hardly identical) triplets.
These similarities are no surprise, as both tunes needed such heroic qualities.
The Music of Star Wars
These posts will help focus and develop my analyses of John Williams' film scores.