How do you, explaining in layman terms, measure the heat of the sun?
We cannot measure the HEAT of the sun: we calculate to the total amount of heat it dissipates per unit of time. What we can do is to measure its surface TEMPERATURE. This is made by analysing its radiation spectrum and correcting for distance and relative speed (radiation shift and not really applicable for the sun). Each “band” of the radiation spectrum corresponds to a particular temperature. In the past, we used a heated filament, and checked only the visible spectrum: point a “telecsope” towards the Sun, and heat the filament in the telescope until its colour matches the colour of the Sun. The temperature of the filament was considered equal to the temperature of the Sun… (after a bit of calculations). For the heat (the amount of energy radiated), we could place a 1 square meter of “heat receptor” exactly pointing at the sun. Since 1 sq m is just a portion of a sphere 150,000,000 km in diameter, multiply the amount of heat received by the ratio, and you get the total amount of HE
