The number 40,000 stood out to me because the Earth is roughly 40,000 kilometres in circumference. Of course, this is 40,000 <i>miles</i>, so it&#x27;s roughly 1.6x the circumference of the Earth.<p>I don&#x27;t really know what the circumference of the moon is. Or, at least I didn&#x27;t. Combine the facts above with the ones in the article, and you discover the circumference of the moon is roughly 1&#x2F;4 that of the Earth.