What was the solar system like when the moon formed?

1 Answer
Jun 21, 2016

It is a scientific surmise that planetesimals (chunks of rocks, metals ice et al) that coalesced to form planets, and planets, were constituents of the solar system, when Moon was formed.

Explanation:

Age of some comets is about 4.5 billion year, Some meteorites are little older. The results come from the study of radioactive decay of matter from space objects, including Earth and the Moon.

Moon is about 4.4 billion years old. Earth is a little older. The solar system, with changing structure and architecture, is older than its separate constituents.

When the constituents were all planetesimals, the solar system was as wide as 100000 AU (called Oort Cloud) or more.

Reference:
:lasp.colorado.edu.bagenal/1010/SESSIONS/11.Formation.html