When Hanks is staring at the moon from his backyard, he holds his hand out in front of him, closes one eye, and 'covers' the full moon with his thumb.

later, when he's circling the moon + looking back at the earth, he does the same thing -- holds out his hand, at arm's length, and 'covers' the earth with his thumb.

This makes no sense.

The earth is the same distance from the moon as the moon is from the earth -- of course!

And the earth is waaaaaaay BIGGER than the moon.

So, if his thumb just covers the moon, then it certainly would NOT cover the earth! The earth would be waaaay bigger than his thumb.