If incandescent lightbulbs have a vacuum inside, why do they get so hot on the outside?

Epic2112@lemmy.world to No Stupid Questions@lemmy.world – 112 points –

Shouldn't the vacuum insulate the glass from the heat of the burning filament?

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Why does the sun heat the Earth if space is a vacuum?

Because of me. Whenever I look up at the sun, I think about the inevitable supernova which the sun sooner or later will turn into. This in turn gives me anxiety and makes me sweat a lot, which heats the earth.

Correct me if I'm wrong but isn't the sun too small to turn into a supernova? and basically will just die a boring death after swallowing all the planets in the solar system and fade into nothingness

A new worry has been unlocked: We're all going to die but not in a cool way and all the other solar systems will think we're lame.

Now I'm worrying even more, and glabal warming will become even worse!

Don't worry, it has zero effect on global warming. These are timescales so vast, humanity will have either wiped itself out or evolved into something unrecognisable long before the sun starts expanding.

Global warming is something that operates on the order of decades or centuries.

If we manage to stop global warming and maintain or better yet repair the state of our climate afterwards, it will take roughly a billion years for the sun to get 10% hotter and boil off our oceans regardless of what we do and longer yet for it to start its red giant phase.

To put that in perspective, a billion years ago life on Earth was all single celled.

Not sure if you're serious, or expanding further on the running joke.

Thank you for the explanation, but outside of the joke I am fully aware of the time scales and origin and consequences of global warming. :)

global warming is definitely something it makes sense to worry about and which there's still some chance to mitigate the worst effects of.

The sun expanding - or even the much earlier effects before that happens, as the sun gets hotter - will happen on such long time scales that there simply won't be any humans at all; most species only last about a million years or so, vastly less time than we're talking about.

We might well make the planet nigh uninhabitable in considerably less than one-millionth of the sun-being-a-major-problem time. It's like worrying about the bridge maybe rusting dangerously a few decades from now, while not paying attention to the truck that has just veered onto your side of the road and will surely hit you in the next few seconds. You need to take evasive maneuvers, not worry about the bridge.

The vast majority of solar systems have significantly smaller suns with equally lame or lamer endings.

That said, because the sun is slowly getting hotter over the ages the older it gets, the Earth's oceans will have boiled off before the sun starts expanding.

basically will just die a boring death after swallowing all the planets in the solar system

Not all the planets, no. Mercury and Venus, sure. The earth's orbit will move somewhat further out when the sun expands, and probably won't be swallowed but it will at least be well baked.

Not quite that large. At the peak of its red giant phase, the sun's size will reach just about Earth's current orbit. Quite possibly the Earth will remain just slightly outside the sun due to the orbit becoming larger to compensate for the sun's decreasing mass, but the Earth's oceans will have boiled off before the sun even enters its red giant phase, because between now and then the sun will get progressively hotter over the millenia (well, technically this slow increase in average sun temperature has been going on for ages already, it's just really slow and masked by several cycles).