Sometimes we forget just how much solar energy is hitting the Earth at any time*. This grown-up version of burning things with a magnifying glass is a good reminder, and shows very well why concentrating solar power has such a bright future.
Please don't try this at home!
*"The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year. In 2002, this was more energy in one hour than the world used in one year." (source)
In other words, that's an average of about 1,000 watts per square meter on the surface of the planet at noon on a cloudless day.