If I put the word "over" in my answer, is it wrong?
The "over" in
- "... any water [that] the moon may have had to leak out into space over the 4.6 billion years that it has been in existence."
means = during the period of
OED:
over: 21. [...] for a period that includes.
This is not the same as the "over" in
- "The moon is over 4.6 billion years old."
OED
over: 13. In excess of, above, more than (a stated amount or number).