Currently we are doing environmental physics in Physic HL and mainly talking about the energy received by Earth, for example, from the Sun.
σ is the Stefan-Boltzmann constant, which is approximately 5.68×10-8
ɛ is the emissivity of the object’s surface
Freeman also talked albedo (e), and after doing some research online, I found that there is a difference between these two terms.
ɛ (emissivity) is the emissivity of the object’s surface
e (albedo) is the percentage of light energy being reflected away
So if the body is not transparent, ɛ+e should equal to 100% or 1.0.