> or being able to blot out the entire planet with your thumb held at arm's distance, as was the case for the guys that made it to the moon
At first I didn't believe you, but some quick math confirms this. The angular size of the Earth from the moon is 1.9 degrees, and the angular width of your thumb at arm's distance is about 2 degrees.
"It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small." - Neil Armstrong
At first I didn't believe you, but some quick math confirms this. The angular size of the Earth from the moon is 1.9 degrees, and the angular width of your thumb at arm's distance is about 2 degrees.