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How would you detect something like that? A primordial black hole the mass of a small asteroid with a tiny absolute magnitude? If such a thing existed, there
by Roboprog 7y ago
How would you detect something like that? A primordial black hole the mass of a small asteroid with a tiny absolute magnitude?
If such a thing existed, there would likely be more than 1. How long would it take such an object to consume a star like our sun if it grazed or hit the star, vs a harmless hyperbolic flyby?
- sbierwagen 7y agoHere's a Hawking radiation calculator that you can use to get an idea of some of the numbers involved: https://www.vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati... Using this calculator, we find that a black hole with the mass of 433 Eros, 6.687E15 kg, would be quite hot, some 18 million kelvin, but emitting just 8 watts of power, and be 0.009 nanometres in radius. Pretty hard to find. Let's try something smaller. 162173 Ryugu, the rock that Hayabusa2 landed on, is only 4.5E11 kg. This gives you a much brighter hole: 1758 megawatts at 2.72657E11 kelvin. Interestingly, this may make it harder to detect! Its blackbody emission peak is at 9,211 KeV, and the Chandra X-Ray observatory only goes up to 10 KeV. (Focusing very-high-energy photons is not easy) You'd have to detect it from the fraction of total power it emits lower down in the spectrum.