The extremely low temperature o outer space can be explained as?

The extremely low temperature of outer space, typically around 2.7 Kelvin (-270.45 degrees Celsius), is primarily due to the vast emptiness and lack of matter in the universe. This temperature corresponds to the residual heat from the Big Bang, known as the cosmic microwave background radiation, which permeates space. In the absence of significant thermal energy sources, space cannot maintain heat, leading to its frigid conditions. Additionally, the expansion of the universe contributes to the cooling of space over time.