relationship in sentences

[SoulSeeker]

Hi Great Teacher Alan,

For the following sentence;

Gravitational waves are disturbances or ripples in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light.

1) is "generated by accelarated masses" acting as an adjective to describe the object "disturbances" and "ripples in the curvature of spacetime"?

2) what is "that propagate as waves......speed of light" referring to? Is "that" indicating the first main sentence of "Gravitational waves are disburbances or ripples in the curvature of spacetime"?

I would greatly appreciate if you answer with enough details, as I am learning English. Thank you Alan.

[Alan]

1. (Essentially) yes. This is a participial phrase adjectivally postmodifying plural nouns "disturbances (in...spacetime)" and "ripples (in...spacetime)". (Common sense naturally excludes the noun "spacetime" itself as a possible referent.)

2. The comma separating "masses" from relative pronoun "that" indicate that the antecedent of the relative clause "that propagate as waves...speed of light" is likewise "disturbances (in...spacetime)" and "ripples (in...spacetime)".