2 the Moon and Mars

I went to the well and whence i arrived It wasn't so much as dry as had moved altogether And upon the journey back i took a stroll through some heather course as leather And despite all of my endeavour and best intentions i am still yet to discover a unit of measure To calculate exactly how much rain fall's in the Saharan desert during the dry season And why on earth would i Because i am probably never ever going to get to go But then again Come to think of it ive never been to the Moon or Mars neither