Observing the stars, we notice that some have different colors; many appear white, but there are also stars with a reddish or bluish tint. The difference in the colors of the stars is a crucial clue for measuring their temperature.
Heat Radiation (Blackbody Radiation)
In the mid-19th century, numerous attempts were made to find the connection between the temperature of dense bodies and the heat radiation they emit. This radiation is also called “blackbody radiation,” but we will refer to it as “heat radiation” for simplicity. These experiments were conducted using a device called a spectrometer.
