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Excuse me if this is a silly questions, but you got my imagination going. >A tennis ball mass black hole would go right through the Earth without too much fuss

Excuse me if this is a silly questions, but you got my imagination going. >A tennis ball mass black hole would go right through the Earth without too much fuss. The black hole's radius would be too small (smaller than an electron) to cause any damage. Is it possible that tiny black holes of this size could be travelling through the earth at a regular basis? Do we have the means to reliably detect black holes that small?

spartanatreyu 4y ago
Well there's two factors preventing that: 1. The smaller the black hole, the brighter and shorter lived it is. To get the black hole to live for any decent amount of time, it'd have to be travelling close to the speed of light for the effects of time dilation to extend it's life time from our perspective. 2. Detecting gravitational effects on a small scale is stupidly hard because of how weak gravity appears to be (compared to the other 3 forces: strong nuclear, weak nuclear, electromagnetic). If you were to shine a laser and the tennis ball massed black hole travelled through the path of the laser, you wouldn't see any light missing because the wavelength of light would be larger than the black hole. If you stopped the black hole (so it's not moving close to the speed of light), and tried to shine the laser at it for a greater effect: not only would you not see less light, you would actually see light shooting out of it so bright it'd be like putting your eye against many many atomic bombs because the Hawking Radiation would be so strong. (It'd also destroy itself in a blink of an eye) You can increase the mass of the black hole to make it cooler and live longer. A 1,000 metric tonne black hole would live for around 46 seconds shedding radiation at an ever increasing amount before exploding into nothingness again. Assuming you could filter out the light coming from the black hole, you might see the phase of the laser light shift, but it'd all still end up at it's destination. The greater problem would be trying to figure out how to shield the Earth from the amount of light shooting out of it.
- k1ll3r 4y ago
  Can we build a Black Hole Bomb?
  - spartanatreyu 4y ago
    Yeah we could shoot a black hole at the right mass (this is tunable) so that it evaporates on the target. There's some other approaches too: - Move a larger black hole into the target planet (this would require so much energy that other approaches would be better). - Send a device to the target planet that generates a black hole massive enough to live long enough to oscillate through the planet back and forth, consuming the planet from the inside. It would take 600 quadrillion metric tonnes of mass to form a black hole 1 nanometer across, so this could be difficult to start. - Create a black hole to power a ship's thrusters (Kugleblitz drive) to smash into a target at speeds approaching the speed of light.
- simiones 4y ago
  Note that, without a consistent theory of quantum gravity, we don't know if black holes of such sizes can actually exist; and unless we happen to detect some, we don't actually know if Hawking radiation exists - it's not something that can be observed for a stellar-mass black hole in realistic time frames (a stellar mass black hole is predicted by the theory to evaporate after ~10^64 years - so the evaporation is far too slow to be observable; further, in the current age of the universe, the temperature of the cosmic microwave background is too high compared to the temperature of the Hawking radiation emitted by a stellar mass black hole for it to be observable, even theoretically).

spartanatreyu 4y ago

Well there's two factors preventing that: 1. The smaller the black hole, the brighter and shorter lived it is. To get the black hole to live for any decent amount of time, it'd have to be travelling close to the speed of light for the effects of time dilation to extend it's life time from our perspective. 2. Detecting gravitational effects on a small scale is stupidly hard because of how weak gravity appears to be (compared to the other 3 forces: strong nuclear, weak nuclear, electromagnetic). If you were to shine a laser and the tennis ball massed black hole travelled through the path of the laser, you wouldn't see any light missing because the wavelength of light would be larger than the black hole. If you stopped the black hole (so it's not moving close to the speed of light), and tried to shine the laser at it for a greater effect: not only would you not see less light, you would actually see light shooting out of it so bright it'd be like putting your eye against many many atomic bombs because the Hawking Radiation would be so strong. (It'd also destroy itself in a blink of an eye) You can increase the mass of the black hole to make it cooler and live longer. A 1,000 metric tonne black hole would live for around 46 seconds shedding radiation at an ever increasing amount before exploding into nothingness again. Assuming you could filter out the light coming from the black hole, you might see the phase of the laser light shift, but it'd all still end up at it's destination. The greater problem would be trying to figure out how to shield the Earth from the amount of light shooting out of it.

k1ll3r 4y ago
Can we build a Black Hole Bomb?
- spartanatreyu 4y ago
  Yeah we could shoot a black hole at the right mass (this is tunable) so that it evaporates on the target. There's some other approaches too: - Move a larger black hole into the target planet (this would require so much energy that other approaches would be better). - Send a device to the target planet that generates a black hole massive enough to live long enough to oscillate through the planet back and forth, consuming the planet from the inside. It would take 600 quadrillion metric tonnes of mass to form a black hole 1 nanometer across, so this could be difficult to start. - Create a black hole to power a ship's thrusters (Kugleblitz drive) to smash into a target at speeds approaching the speed of light.
simiones 4y ago
Note that, without a consistent theory of quantum gravity, we don't know if black holes of such sizes can actually exist; and unless we happen to detect some, we don't actually know if Hawking radiation exists - it's not something that can be observed for a stellar-mass black hole in realistic time frames (a stellar mass black hole is predicted by the theory to evaporate after ~10^64 years - so the evaporation is far too slow to be observable; further, in the current age of the universe, the temperature of the cosmic microwave background is too high compared to the temperature of the Hawking radiation emitted by a stellar mass black hole for it to be observable, even theoretically).