Mirror cleaning

Solar energy plants are usually in deserts, where lots of sand and dust blow around. So, here's a specialized truck that delicately cleans the mirrors. Cool. 

It takes trucks three days, or rather nights, to clean the 250,000 mirrors at one plant in the UAE. 

http://www.popsci.com/cars/article/2013-07/truck-keeps-worlds-largest-solar-plant-squeaky-clean

http://youtu.be/XYWkQiXvwXw

Sent from my iPhone

Time lapse of airline jet flights

The commentary describes the predominating flights at different times:
Commentary on this video describes the flights predominating:



Here's world airline flights animated:


Here's a nice representation on a sphere:


And here's when all flights dropped out of the sky on Sept 11.

Solar Impulse - Wikipedia, the free encyclopedia

Have you heard of this solar-powered plane that has enough batteries to fly for 9 hours at night?
Cool.

http://en.m.wikipedia.org/wiki/Solar_Impulse