Lydian is the major scale with one note moved. Raise the fourth degree a half-step and everything changes.
That single alteration changes where the music wants to go. In a major scale the fourth resolves down to the third — a 4–3 suspension is some of the strongest voice leading available, and it’s how cadences settle. Lydian gives that up. The raised fourth leans the other way, acting as a leading note to the fifth and pulling upward instead of down. The mode doesn’t lose its gravity so much as invert it.
That’s the sound directors reach for when they want awe rather than triumph. Not a fanfare telling you something is important — a harmony that lifts instead of settling.
James Horner’s Universal ident is seven seconds of it, and it’s probably the most-heard Lydian phrase ever written.
Jerry Goldsmith’s Enterprise theme from Star Trek: The Motion Picture does the same at length — brightness that reads as distance rather than victory.
The signature chord follows from the same note. In F Lydian the supertonic is G–B–D: major, where F major would give you G minor. That major II is the Lydian sound in harmonic form, and I–II is where most of the colour lives.
It also gives you a way out. The raised fourth is the leading note of the key a fifth below, so if the harmony underneath implies that key, the mode reads as ordinary major and your tonic becomes a passing IV. That ambiguity is controllable, and useful. Slide the B down to B♭ and the II becomes a V7 — the natural fourth then resolves to the third exactly as it always did. Lydian colour, chromatic descent, conventional cadence, three chords.
The raised fourth isn’t a constraint. It’s a door: hold it and the music floats, lower it by a half-step and you’re back in functional harmony with a line that sounds inevitable.