The moon is actually more useful than the sun since the moon gives us light at night when it's dark. The sun only gives us light during the day when it's already bright out.
I actually figured it out last night but not until after I had already posted for #10 so I couldn't post it. I figured it would be okay now though. I thought they were all a bit hard!
I don't have to try to make this puzzle hard, as I do with so many others. These are somehow naturally difficult. Your timing was perfect, oldbroad.
The moon is actually more useful than the sun since the moon gives us light at night when it's dark. The sun only gives us light during the day when it's already bright out.