[Carl]

http://news.bbc.co.uk/1/hi/sci/tech/4357613.stm

[Andreas]

So then, it will slowly suck Earth into it, growing bigger and then finally consuming everything in our solar system? Great.

[aldo_14]

I'm somewhat amused that they're not sure - "What do you mean, you think you have a black hole in your office?!"

[übermetroid]

sounds like something humans would do.

[Night Hammer]

did they shut it off?

[karajorma]

It lasted billionth of a second and then disappeared again. As long as you're careful with them quantum black holes are actually quite a good energy source. Feed them matter and they spit out gamma rays. Much better than anti-matter because you only need one black hole. No need to go through a produce-destroy cycle (Which suffers from the fact that it takes more energy to make anti-matter than we get out of it anyway).

[vyper]

Look at it this way, if they ever screw up and we end up in a black hole we'll never know.

[Carl]

kara, that may be true, but it's a good way of storing and transporting energy from one place to another.

[Janos]

How wide must a black hole's event horizon be for it being a threat? I have a feeling that small black holes vanish pretty quickly.

[Bobboau]

it's not about volume, it's about mass (although the two are directly linked) it needs to have enough mass to have gravity suficent to pull in nearby matter at a rate faster than it evaporates, a black hole with the mass of one atom isn't going to last very long.

[karajorma]

Yep. This thing is tiny. The world isn't going to go spinning into oblivion from it any time soon.

[Ashrak]

wohoooooooot everlasting power source ... if we get to make a bigger PS just feed it matter and you get powah as long as you can contain the PS

[Bobboau]

now if we start getting into makeing mini black holes we realy need to be doing it on the moon or something, so we don't end up with our planet crushed into a marble sized speck.

[Ashrak]

bob .... if we make a big blob .... it wont matter if its on jupiter since it will still anahilate earth with it massive gravimetric shear

[Carl]

Originally posted by Janos
How wide must a black hole's event horizon be for it being a threat?

anything greater than zero. what really matters is how much matter is nearby (and how close it is) during it's lifetime.

a black hole with the mass of a bowling ball will have the same gravity as a bowling ball: not much. however, the difference is that since the black hole is a point source of gravity, if you put your hand inside the radius of a bowling ball away from it, instead of the gravity pull your hand outward like a bowling ball would if you put your hand in it, the black hole's effect will increase exponentially as your hand gets closer to the center. If it gets close enough, it'll gobble it up. of course, your whole hand won't be able to fit in such a tiny space, but the atoms in your hand that are close enough will. this then increases the mass, which increases the gravity, which increases the effective range, which means it'll eat more, which increases the mass, ad infinitum.

[Ashrak]

oh dont foget the temporal displacement

[Bobboau]

Originally posted by Ashrak
bob .... if we make a big blob .... it wont matter if its on jupiter since it will still anahilate earth with it massive gravimetric shear

yes becase it'll magicly make more mass than the moon has

[kasperl]

Bob is right, if we do it on the moon, we might loose the moon and have a black hole with the moons mass in its place, but the only true effect is that it looks like the moon is gone.

[karajorma]

Yep. Wouldn't even change things like the tides etc most likely.

[Ashrak]

pardon my stupidity ... but dont black holes .... like move?