Assertion: matter's effect | /r/HasProperty | observed
Facets:
value: readily
type: MANNER
value: by using more completely burned material
type: MANNER
value: many times
type: TEMPORAL
Source sentences:
text: This so-called "gravitational lensing effect" has been observed many times.
text: These effects can also be obtained by using more completely burned material, which contains more ash and little black carbon.
text: And matter has mass, creating the force of gravity, the effects of which can be readily observed.
text: There are some hints that such effects may already have been observed.