TASK DEFINITION: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
PROBLEM: Ca-Al-rich inclusions – the oldest known solid bits in meteorites formed within the solar system – are 4.567 billion years old .

SOLUTION: Calcium – aluminium-rich inclusions — the oldest known solid constituents within meteorites that are formed within the Solar System — are 4.567 billion years old , giving a lower limit for the age of the Solar System .

PROBLEM: The Greek Orthodox Church of Antioch is a group of Christians .

SOLUTION: The Greek Orthodox Church of Antioch , also known as the Antiochian Orthodox Church and legally as the Greek Orthodox Patriarchate of Antioch and All the East , is an autocephalous Greek Orthodox Church within the wider communion of Eastern Orthodox Christianity .

PROBLEM: Those in the halo contain many more stars and are much older than the less dense open clusters in the disk .

SOLUTION:
Globular clusters are found in the halo of a galaxy and contain considerably more stars , and are much older , than the less dense , open clusters which are found in the disk of a galaxy .