I need help trying to understant this simile... i want to understand why Bradbury compares Clarisse to a clock

Question

" He looked at the blank wall. The girl's face was there, really quite beautiful in memory: astonishing in fact. She had a very thin face like the dial of a small clock seen faintly in a dark room in the middle of a night when you waken to see the time and see the clock telling you the hour and the minute and the second, with a white silence and a glowing, all certainty and knowing what it had to tell of the night passing swiftly on toward farther darknesses, but moving also toward a new sun." - Ray Bradbury Fahrenheit 451

PLEASE help me understand this simile from FAHRENHEIT 451

Thank you!

Answer 1

I think it means that she knows something significant because her face cannot hide the truth