Probably a stupid question, but will we ever have something like a microwave to make things cold? Is there a reason this can't exist?

Melatonin@lemmy.dbzer0.com to Asklemmy@lemmy.ml – 486 points –
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You can dump energy into something by blasting photons at it, because photons carry energy. You can't do the reverse because you'd need to use particles with negative energy. Either that, or you'd need to suck photons out of the food, but it doesn't work that way; things radiate photons at a specific frequency and intensity (called blackbody radiation) depending on how hot they are, and you can't make them emit more energy except by getting them hotter.

Allow me to introduce you to this

https://en.m.wikipedia.org/wiki/Laser_cooling

Can I get an ELI5 of this principle? I read the Doppler cooling part but I can't connect the dots.

Heat energy is the amount of particle wiggling. With precisely tuned and oriented lasers you can clamp a particle in space, thus prevent it from wiggling.

No wiggling -> very cold.

It's like slowing cars by crashing another car into them. But it's photons instead from the exact opposite direction.

A common misconception. Take the so called "light bulb" for instance. People think they emit light. They do not. They ingest darkness. They are dark suckers. They pull in all the darkness around them, but objects get in the way, and that's why there are shadows. And when they're full, they stop working. That's why they have a brown spot when they stop working, they are full of dark.

Don't fall for the light emitting conspiracy. LONG LIVE THE DARK SUCKERS!!!

For a second I didn't think this was a meme, and I was like "I'm pretty sure that's not how it works."

It was a risk not adding /s especially since I tried really hard to not be too absurd as to be obvious. I will take your unease as a compliment :)

Considering room pressure and temperature, things are not cooling at their fastest possible rate. Blackbody radiation isn't the only way things cool down. You are forgetting conduction and convection. Liquid nitrogen can cool things down super quickly.

I'm not forgetting them: they're just but relevant to the way I interpreted the question. I'm assuming OP wants something that works on a similar physical principle to a microwave, not just a fast way to chill things.

Ah sure, yeah, if they want it to actually use radiation, it's not possible.