Here's today's burning question: Why are the cars and bikes that are polished to a mirror finish are so hot to the touch in the sun? Wouldn't common sense say the sunlight reflects away?
Hot Hot Hot. How come?
Jon;
For the same reason we don't leave chrome plated wrenches lying out in the sun here in Arizona.
Sunlight heats an object and then the heated object then radiates the heat away in the far-infrared. Depending on the emissivity of its surface, the object eventually achieves a balance at some temperature between heat absorbed and heat radiated. Although chrome and polished aluminum look shiny to our eyes, we see only a small portion of the light- the "visible spectrum". In the infrared, that surface absorbs heat but it doesn't radiate heat worth a darn so the balance ("equilibrium") of heat in/out is achieved at a high temperature.
Gold looks just as shiny as aluminum or chrome but it has an extremely high reflectivity in the infrared so it stays cool. I can hear Shirley Bassey now.... "Goldfinger......"
Regards, Neil Tucson, AZ