Space probes have yet to reach the area of the Oort cloud.
There have been many theories about Oort clouds and what they contain.
A third of the scattered disc's population is likely to end up in the Oort cloud after 2.5 billion years.
Mac had cut off her arm with a power laser, out in the Oort cloud.
There are lots of comets in your average Oort cloud.
They will want to know we've discovered another Oort cloud, too.
I lurked in this system's Oort cloud for more than a day, trying to make up my mind.
Not every other star has an Oort Cloud, but many probably do.
And then there were all the missions that wound up in Oort clouds.
Out there in the Oort cloud, speeds got even slower.
Słownik astronomiczny