exterior planets in a sentence

1. Triple conjunctions between exterior planets or an exterior planet and a star can only occur when these objects are nearly simultaneously in opposition.
2. Triple conjunctions between exterior planets or an exterior planet and a star can only occur when these objects are nearly simultaneously in opposition.
3. Triple conjunctions between the bright exterior planets are very rare : the last triple conjunctions between Mars and Jupiter occurred in 1789 1790, in 1836 1837 and in 1979 1980.
4. Furthermore, this is the brightest star that can be principally occulted by an exterior planet between 5000 BC and 5000 AD . However, only Mars can do this, and only rarely; the last time was on September 3, 423.
5. It's difficult to find exterior planets in a sentence.