Moth Pee,
 50 miles is a short drive in Texas. That was our drive over to Fort Davis and the McDonald Observatory. Part of the University of Texas, McDonald is one of the largest observatories we have and home to the 4th most powerful telescope in the world. They only open the observation domes at night so to keep birds, and other daytime critters and their messes out of the chambers. But, besides stars, moths also come out at night, and, who knew?, their urine, (really...a moth goes wee wee?), ahem, the urine is very acidic and poses a threat to etching on the complex mirror systems these incredibly expensive precision contraptions use to bring our outer space closer to us. So they clean them 3 to 4 times per week. They do so by spraying a frozen formulation of CO2 that goes on like snow, absorbs all the dust, dirt and moth stuff that has accumulated, dries into a powder and then is vacuumed away. Zero abrasion on the mirrors. I want this for Vilia, our 5th wheel. She's a big lady to wash by hand.

The visit and tour were quite interesting. Our young guide was a space observation junkie and was wonderfully well informed and well spoken. This 4th largest scope is undergoing a $40 million enhancement with two goals in mind: More deeply explore the phenomena of "dark energy" that exists out there and also seek clues as to why the universe looks to be expanding. I'll let them go after dark energy but I have a question I wish I had thought of while there. I've always been under the impression that the universe is endless. (A good thing to think about when you feel a need to self induce a headache). If it is endless, how can it be expanding? It must be the moth wee wee.