Short answers, pulled from the story.
Dutch astronomer Jan Oort presented his hypothesis about the distant reservoir of comets in 1950. He proposed that icy bodies resided far beyond known planets to explain the origin of long-period comets.
The Oort cloud stretches from 2,000 AU to 200,000 AU from the Sun. This distance equates to roughly 0.03 to 3.2 light-years and marks the outer boundary where solar gravity concedes influence.
Estimates for the total mass of the outer cloud may equal five Earth masses though previous calculations reached 380 Earth masses before improved data lowered expectations. No mass estimates exist for the inner cloud as of 2023.
Objects in the Oort cloud formed much closer to the Sun within the primordial protoplanetary disc approximately 4.6 billion years ago. Recent research suggests over 90% of the cloud may originate from protoplanetary discs of sibling stars rather than near our own Sun.
Voyager 1 will not reach the Oort cloud for about 300 years but would take roughly 30,000 years to pass completely through the region. No direct observation is possible with present imaging technology so astronomers rely on indirect methods to study this unobservable area.