A graphic interior look at a tiny black-hole entering and exiting a star
Astrophysicists are examining the possibility for a rather dramatic explanation for the enigmatic Dark Matter thought to comprise a significant fraction of the mass of the universe. While the leading idea for Dark Matter is a WIMP – Weakly Interacting Massive Particle – the particles being sought here make WIMPS look like sissy’s:
These collisions would not destroy the black hole or the star. Although their characteristics are uncertain, Kesden and Hanasoge’s simulations posit that primordial black holes could have masses of 1018 kilograms (a million trillion kilograms, about the mass of a largish asteroid), which is too small to destroy a star as they pass through. “The black hole is like a very dense bullet passing through the Sun, which is like a fluffy feather pillow,” says Kesden.
Would a black hole with the mass of a mountain moving through the earth (Or a human body) be noticeable? I have no idea, but it sure seems like it should.
>1018 kilograms
Copy & paste error. 10^18 or 10e18 kilograms
I assume, without having clicked on the link yet, that 1018 is supposed to be 10^18.
So what is the theoretically smallest mass of a quantum black hole? I though that Hawking’s hypothesis predicted at some point, the mass would become small enough that the black hole would explode , or whatever the term would be the sudden ‘evaporation’ when the mass reached a too small critical state.
Apparently, I need to do some reading on the latest ideas. Got any recommendations for a lay person with a decent math background (I’m an engineer, so I can understand basic Diff Eqs.)?
The link (at sissy’s) is broken, DarkSyde.
I guess it would depend on your definition of a “black hole”. From what I’ve read, they aren’t all supermassive collapsed stars; they just require an insane density. Which means, yes, there might be quantum black holes; amalgams of mass, incredibly dense, but still subatomic. Something like that would indeed pass through you without you noticing; neutrinos do it all the time. And at the scales we’re talking about, the gravitation from one of them wouldn’t affect a human. Even at atomic scales, the gravitation from one of them would be negligible.
@Fastlane: IIRC, the predicted instability of quantum-sized black holes is a result of their surface area to volume ratio being large enough that the Hawking radiation they emit at their event horizon is able to vaporize them in a timespan that’s less than the lifetime of the Universe, making it an event we could potentially observe.
And… I dunno, you’d think that something the size of a mountain but smaller than an atom would still do something to you when it flew through you, but for some reason I’ve got a feeling that it might not. The Lorax is probably right, because even if it did just happen to collide with a subatomic particle it’s not like it’d explode, right? The particle would just vanish into it. I’m pretty sure we wouldn’t notice a half dozen electrons suddenly gone missing from our bodies.
Larry Niven, in a short story, suggested that a black hole’s passage through you could be fatal due to tidal forces disrupting a line of tissue along its trajectory, much larger than the actual circumference of the hole itself.
I think your SISSY link is 404’d, by the way.
Escape velocity of a body of mass M:
v_e = SQRT(2GM/r)
G = 6.67 x 10^-11 [m^3 kg^-1 s^-2]
M = 10^ 18 kg
set v_e to the speed of light and we get r of:
1.49 x 10^-8 m
This is approximately 100 times the diameter of a hydrogen atom (1.58 x 10^10 m).
So it seems that this would be significantly more interactive than a neutrino.
Oops. small typo. The atomic dia. is 1.58 x 10^-10 m.
Here’s the borked link (hopefully)
Thanks Kevin, been happening lately, the site dupes the quotes in the tag for some reason.
@ fastlane:
Indeed, I was halfway through that calculation when I scrolled down. Even more interesting, I solved for the distance at which a 10^18 kg black hole has 1 g (~10 m/s^2) gravity:
a_grav = MG/r^2
a_grav = 10 m/s^2
M = 10^18 kg
G = 6.67*10^-11 m^3/s^2kg
r = 8.16*10^3 m
Significantly more interactive than a neutrino, yes. If that hit Earth, the planet would be basically okay, from a structural perspective, but humans would be borked. Expect show-stopping earthquakes. At the entry and exit points, destruction tantamount to a nuke, and no point taking cover: gravity goes through walls. A human, if hit directly, would be a widely dispersed cloud of organic steam. A star, otoh, would burp and go on with its life.
The Tunguska Event was at one point thought to be the impact of a singularity of similar size (it wasn’t, but it was similar to what the effect of one would be). So, yes, the destruction cause by a quantum singularity impacting the Earth would be enormous, but not disastrous for the planet as a whole.