I don’t understand the meaning of this sentence: ‘One of my earliest memories, from when I was about four, is seeing a speedboat race across a moonlit sky.’
What does ‘a speedboat race across a moonlit sky’ mean?
Thank you for your time!

It doesn’t make sense literally — except, I suppose, in the rather contrived case that the silhouette of the speedboat was seen on the horizon against the sky. It may be describing a fantasy or imaginary scene, or a scene misinterpreted at such a young age, or the speaker may have intended to say “under” rather than “across”.