In the vacuum of space, heat transfer occurs primarily through radiation, as there is no air or matter to transfer heat through conduction or convection as we experience on Earth. The temperature in space, away from any significant sources of radiation, is extremely low, approaching absolute zero (-273.15 degrees Celsius or -459.67 degrees Fahrenheit).
If we consider a hypothetical scenario where the ambient temperature in space is the same as Earth's atmosphere at sea level (around 15 degrees Celsius or 59 degrees Fahrenheit), we need to understand that this would require a substantial source of heat to maintain that temperature. In space, without any insulation or protection, objects exposed to sunlight can reach extremely high temperatures due to the intense solar radiation.
However, even if we assume an equilibrium where the temperature is maintained at 15 degrees Celsius, the heat loss through radiation would be significant. Objects in space would radiate heat away, causing their temperature to drop rapidly. The lack of matter to conduct or convect heat would make it challenging to sustain such a temperature.
In summary, in the absence of significant heat sources or insulation, the ambient temperature in space would rapidly approach the extremely low temperatures near absolute zero, regardless of the hypothetical atmospheric composition matching Earth's sea-level conditions.