Space is a cold place. It’s also very cold. In fact, there is no such thing as the temperature of empty space. We can only talk about the temperature of an object if it is there. According to science, heat is a measure of how mobile objects are. Hot objects move fast, cold objects move very slowly. If atoms reach a final rest, they are at absolute zero (-273,15°C).
The transfer of heat is possible in three ways. If you heat one end of a metal rod, the other end will also start to heat up. This happens as a result of the iron being able to transfer heat from one end to the other. Air can also transfer heat from one place to another. This is the second method. On Earth, energy transfer occurs when atoms in your body collide with air or water atoms. Nature requires that all atoms move at the same speed; it wants the temperature to equalize. Since there is no air or water in space, heat is transmitted only by radiation. We owe this to photons.
Heating occurs when the energy of photons is absorbed by objects. If an object can absorb more of the photon it emits, it heats up. Otherwise, it will cool. For example, the metals used on the International Space Station are protected by special coatings because the sun’s rays can heat them up to 260 degrees. But when the sun’s rays do not fall on them, they can cool down to -100 degrees.
The farther you get from the sun, the greater the decrease in temperature. Pluto’s surface is -240 degrees. If we go a little further, we will encounter temperatures between 10 and 20 degrees above absolute zero. However, if we were to reach one of the most distant and empty regions of the universe, away from all celestial bodies, the lowest value we could encounter would be -270,45°C. Because this value is the value caused by the radiation spreading to the entire universe from the cosmic microwave background radiation. But it is also very difficult to come across. The coldest place to be identified so far is the Boomerang Nebula with a record -272°C.
So why can’t the sun’s rays heat the space? Because space is not in a structure to trap and hold heat. On the other hand, there is an atmosphere on Earth, so the sun’s rays can be absorbed by the air at a certain rate.