Comment by isoprophlex

4 days ago

Commenting to reinforce this idea: I'd love an AR approach where I can pin a black hole with a given radius into my living room, and walk around it!

The geosharing augmented reality thing mentioned by the parent comment is very very cool too, I'd pay a few bucks for that! Maybe make it social by letting black holes that people drop somewhere IRL merge, etc...

Reach out to me if you eventually would like to spin up a cheap bit of infrastructure to host the data of where people dropped their black holes, and need some help with that!

It would be neat to also get stats about the black hole depending on where you are in relation to it (obviously this breaks physics as a micro black hole would immediately fall into the earth). Everything is based on the hawking radiation calculator: https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati...

Example: Set mass of black hole to 1e12 metric tons, or about 100,000 great pyramids.

This has a schwarzschild radius of 1485 femtometers (1 femtometer is around size of a proton).

Nominal luminosity is 356 watts. You could power your computer! Lifetime is 1e12 gigayears.

An interesting thing comes with gravity. Gravity at the schwarzschild radius for this mass is 3e28 m/s^2, but this is at a smaller-than-an-atom radius.

If you put your hand within a foot of it, gravity would be 700,000 m/s^2.

You would need to be at a distance of 270ft to experience gravity from it that compares to earth (9.8 m/s^2).

  • That is 356 watts of luminosity from something so small?! Whoa! It says the peak of the radiation has an energy of 41 keV though, so better not look at it directly (:

    I tried plugging in some other numbers and, at first confusingly, found that the luminosity goes up at lower masses?! But of course it radiates from it's outer shell, not the entire volume.

    Wonderful tool, imagine playing with those parameters in AR

    • Yes, this is one of the wonderful crazy properties of black holes: they get hotter as they evaporate! (More precisely, the Hawking temperature is inversely proportional to the mass!)

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