Final answer:
The temperature of a distant object's surface can be estimated by its color, with blue indicating higher temperatures and red indicating cooler temperatures, a concept based on Wien's law. The Sun appears slightly yellowish from Earth due to atmospheric effects but would seem white in space. Color as an indicator of temperature is consistent across various distances.
Step-by-step explanation:
Understanding Stellar Temperatures Through Color
How hot the surface area of a distant object depends on the color of light we observe, which is a concept related to Wien's law. For instance, the hottest stars, which can reach temperatures over 40,000 K, emit most of their light at blue wavelengths. Conversely, cooler stars, with temperatures around 2000 K, emit predominantly red light. Our Sun, with a surface temperature of approximately 6000 K, would appear white in space as it emits an almost equal mix of reddish and bluish wavelengths, but from Earth, it appears yellowish due to atmospheric scattering of blue light.
An important aspect of understanding this relationship is that the color of an object, like a star, is indicative of its surface temperature and is not affected by distance. Thus, using color as a 'thermometer,' a blue star would be hotter than a red one. Moreover, as an object's temperature increases, it emits at shorter wavelengths. Consequently, a body increasing in temperature from 1000 K to 1,000,000 K would transition from glowing red to a bright bluish-white.
This thermal emission is a form of blackbody radiation and applies to the infrared spectrum as well. Earth's surface and atmosphere, with typical temperatures around 300 K, emit infrared radiation with a peak wavelength of approximately 10 micrometers, influencing the practice of infrared astronomy.