Luke:

“Daddy, You know Mars moons is going to crash into Mars and break it pretty soon.

We read about it in the Mars book.”

Daddy: “Thats right, I think it is a few million years away from happening.”

Luke: “Yeah, its not that soon.”

Daddy: “Does this news interfere with your planned visit?”

Luke: “No, I will grow up in about a million years, or maybe a hundred, so it will be before Mars stops working.”

Daddy: “Ok”