If a microscopic black hole with a mass of about 500 billion kilograms and a horizon the size of an atomic nucleus were dropped onto the surface of the Earth what would happen?
Assuming the hole would orbit inside the planet and consume said planet as it went along its merry way how long would the earth last?
Any conjectures about what other kinds of wierd things might happen
Anyone remember the name of the Sci Fi book that was written about this very subject?
IANAPhysicist,but i believe I’ve heard several times that a black hole becomes less dense with relation to it’s mass. I’m not sure how unreasonable your mass to size ratio is, considering i’m not sure how large a solar mass is in kilograms, but it’s probably a little off. Anyways,I don’t know how you would get a black-hole inside the planet without tearing it open… but i’m sure if you did it would implode and comense on sucking up the rest of the solar system.
The story (not book) you’re looking for is “The Hole Man”, by Larry Niven, and it’s Mars that gets eaten, not the Earth. If nowhere else, you can find it in The Hugo Winners, volume (I think) 3.
The important thing about a small black hole is not its density, but its temperature: Without doing the calculations, I’d say that one that small would probably evaporate completely before it hit the surface. The net result would be a huge explosion, releasing 500 billion kilograms of energy. Again, I don’t know the exact numbers, but I imagine that that’s enough to destroy the Earth.
Now, supposing that it didn’t evaporate (like in Niven’s story; Hawking radiation wasn’t known at the time), then it’d eventually eat the Earth, and in the meanwhile, cause a hell of a lot of damage via tidal forces. After it had eaten the entire planet, it would just continue to orbit in the Earth’s prior orbit, and not eat anything more than the stray space dust which happens to hit it. Gravitationally, at distances much over a few meters (the Schwartzschild radius of a hole of that mass), it’d behave just like any other mass equal to the Earth plus half a billion tons. Things wouldn’t get sucked into it any more than they would be into the Earth.
Actually, Chronos, he’s looking for Earth, by David Brin. Tiny singularities and gravity lasers. Good stuff.
Some synopses (Amazon’s sucked):
http://www.phys.tcu.edu/~dingram/books/rev05.html
http://www.babesinspace.net/book/reviews/38.html
http://www.catch22.com/~espana/SFAuthors/SFB/Brin,David.php3
http://www.ludd.luth.se/~doomdark/brin.html
The book Hyperion also features a singularity escaping and digesting earth over a period of about 50 years.
Kip Thorne says in “Black Holes and Time Warps” by pg. 447 that a hole this size “should have evaporated away by now and BHs a few times heavier than this should still be evaporating strongly”
So he seems to be implying that primordial holes of this size can last a pretty long time. Although I’m not sure how massive the hole would have been 15 billion years ago.
Thanks for the book references, and I’ll probably buy them, but they weren’t the one I was thinking about.
In the one I read the hole orbited through the center of the earth and due to the earth’s rotation it would pop through the surface at a different place each time poking (eating?) holes in whatever it encountered. The hole was deliberately planted by some advanced alien race, and the earthlings encountered some kind of strange creature that had no way of ingesting food or eliminating waste. Unfortunately that’s all I remember.
But wait, I seem to also remember that some other alien race showed up to rescue some of the earth’s population.
Ring:
It wasn’t a black hole, it was neutronium, and the book was The Forge of God by Greg Bear IIRC.
I know nobody’s asked about it, and it certainly isn’t the story the OP asked for, but you should look up Tony Rothman’s The World is Round. Black Holes deliberately placed at the center of a planet for industrial purposes. Also one of the few sf novels written by a physics grad student (or at least one of the few that got published).
Scylla
I think that’s it. The title sounds very familiar.
Thanks
WRT the mini black hole Thorne says the Hawking radiation would be gamma rays which are extremely high energy particles (ionizing radiation.) I would guess this would zap a lot of people except I have no idea how to calculate the power that would be radiated.
I’m not physics major,nor have I even had physics yet, but I"ll go by some of the many I’ve seen on the lovely Discovery Channel :). If the black were within the earth, let’s forget about how it got there, it would mostlikely suck the mass of the earth into it rapidly, not saying how rapidly, but enough to implode. I’d say that the implosion might do something like a small supernova or something along the lines of that.
Mr Strange, I think you would be surprised by how much energy a supernova releases, even a so-called “small” one. If such an explosion occured in the region of space formerly 
occupied by the Earth, I am certain it would take out the entire Solar system. There is quite a bit of difference between planetary phenomena (even those involving an entire planet) and stellar phenomena. Indeed, supernovae can exceed the energy output of an entire galaxy.
Here’s a site with some info.
Here’s another site with some info. The author concludes:
Wouldn’t a black hole with an event horizon the size of an atomic nucleus just slip through the molecules of earth’s crust?
Hmmmm… A tiny black hole orbiting through the Earth… The book I was thinking of though of was The Doomsday Effect by Thomas Wren. IIRC, it was pretty lousy, but I was about 15 when I read it.
… and when someone who doesn’t know how to type says a book is pretty lousy, then stay away from it.
[sub]note to self: use preview button