Currently we are doing environmental physics in Physic HL and mainly talking about the energy received by Earth, for example, from the Sun.

Power radiating from an object is calculated by
$P=\sigma \varepsilon AT^{4}$

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.