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?
In: 19
The extremely simple answer is this:
The heat coming off of the sun does so in the form of countless tiny little bullets. Each bullet delivers a tiny packet of heat to whatever it runs into. Stuff like you or me or planets are really, really big targets that get hit by lots of bullets, so the tiny heat packets from the constant spray of bullets adds up, and rather quickly, too.
Space itself, at least in our neck of the woods, is never *quite* empty. There’s always going to be a stray particle or two or ten wandering around. When people talk about the temperature “of space”, they mean this stuff.
This is an extremely vast and spread out cloud of targets, where each target is so small that it’s in the same order of the size as the sun’s little heat bullets. The sun is effectively machine gun firing bullets at… other bullets. From light-minutes away. As you can imagine, hits aren’t very common purely because the target to hit is so ridiculous.
Even if a hit does happen, the next hit will take so long that the particle struck will probably have ample time to cool off before then. It’s like the universe’s slowest, most inefficient rotisserie.
The end result is that space itself is quite cold, while large things in the same exact spot won’t be. Bigger target = more hits = more heat.
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