If the Sun is able to keep Earth warm while being millions of miles away, shouldn’t it get warmer and warmer the closer you get to it (like when you go to space)? Like how it would get warmer if you were to approach a burning house for example?
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Temperature measures heat energy in matter. No matter means no temperature.
The sun radiates energy as light. When radiated light interacts with opaque matter, the matter converts light into heat (infra-red light) itself begins to radiate energy.
The closer an object is to a radiant energy source, the more of the source’s energy interacts with the object. This is why fires feel hotter as you aporoach them. But the radiant energy doesn’t heat anything until it interacts with something, like your face.
Air is transparent to light, but relatively opaque to infra-red. The sun’s light transits the atmosphere and heats the ground. The ground then radiates infra-red which heats the air.
The space between the Sun and Earth contains no meaningful matter, thus temperature doesn’t really mean anything there. So it’s not that the space is cold. Just that temperature is meaningless.
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