The sun warms up our planet but space is cold. If I lit a candle and stood 20 feet away, I could see the light but not feel the warmth. So, why do we feel warmth from the sun but space isn’t warmed by it?
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Space is (mostly) empty, so the sun can’t heat it up because there’s nothing to heat up. If you put an object in space, that object is going to have some heat (all objects do) and it’s going to radiate heat to space. If that object can also evaporate (like moisture on exposed skin could), it will also lose heat by evaporation. That’s why when it comes to exposing living things to space, space is most often thought of as freezing.
However, if the object in space is also being lit by the sun, it’s going to receive heat from the sun’s radiation. So something like a satellite in orbit (or the surface of the moon) is going to get extremely hot on the sun side and extremely cold on the shade side. Managing this heating and cooling is a big part of spacecraft design (and why things sent to space are often either shiny or white – it’s to reflect the sunlight).
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