The KugelBlitz, or:

[CptRichardson]

What in the Jeb does it take to make a Black Hole entirely out of light?

It seems counter-intuitive at first to think that a black hole might be made out of light. Then again, given that E= mc^2, why can't the equation be reversed? And the very concept is rather terrifying in an even more lovecraftian way than a normal black hole, given how wrong things supposedly get even before you get a singularity point of light built up. But, this might explain how galactic core supermassive black holes get made, perhaps.

 

[Bill Phil]

Mass and matter are properties of energy. So you can get mass where you thought none was.

[PB666]

3 hours ago, CptRichardson said:

What in the Jeb does it take to make a Black Hole entirely out of light?

It seems counter-intuitive at first to think that a black hole might be made out of light. Then again, given that E= mc^2, why can't the equation be reversed? And the very concept is rather terrifying in an even more lovecraftian way than a normal black hole, given how wrong things supposedly get even before you get a singularity point of light built up. But, this might explain how galactic core supermassive black holes get made, perhaps.

 

Don't forget however that light travels as a wave function that does not age in and of itself as it travels. It woukd be excessive difficult to have a high enough density of wave function energy in one space to create a schwartzfield radius. 

The geometry of quantum space time maybe important, the geometry of such a light black hole might have a shape like a dandelion, but since much of the mass of the dandelion is more in the peripheri than the center the dandelion would have to have  many more hairs to have sufficient enough mass to form, with some photons being captured and others diffracted. 

We did the calculation here once chach the files. To make a black hole large enough to create a drive you would have tobstart using intensely ineregetic lasers in a sphere 200 or more light years across aiming at something about the sizebof an atom. Practically speaking it is not possible to do. 

[Snark]

Several problems you're going to run into, which revolve around the fact that you need really insane densities to get a black hole to form, and that's a very hard thing to do with light.

Start with the fact that light has wavelength of a finite size, and can't be focused smaller than that.  (That's why we have to use electron microscopes to see details on objects smaller than a few microns in size.  Light is just too big.)  So you can't, for example, use visible light to form a black hole  only (say) one nanometer across, because light has a wavelength of several hundred nanometers.

Therefore, that puts an effective minimum size for the black hole of, say, around one micron across.  Let's say a Schwartzchild radius of 500 nanometers.  If I'm doing my math correctly, that would translate to a mass of around 3.3e20 kilograms, i.e. 330 quadrillion metric tons.

As pure energy, in the form of light.  Focused into a pulse  that would have to be no more than about 1.7e-15 seconds in duration, i.e. one 600,000th of a nanosecond.  The needed power would be 1.8e52 watts.

Just to put things into perspective:  The total energy output of our sun is, IIRC, around 3.8e26 watts.

So all you're asking is to generate an energy pulse equivalent to 48 trillion trillion times the power output of our sun-- or, if you prefer, 3.6 quadrillion times the combined power output of the entire Milky Way galaxy.

Or, put another way:  imagine you had a magic capacitor in which you could store up all the energy you want, then release it instantaneously.  Charging up that capacitor with enough energy to create one of these micron-sized black holes would require capturing the entire energy output of our sun for over 2500 years, in order to release it in one 600,000th of a nanosecond.

That seems like... ah, how to put this kindly ... a bit of a tall order.

So I wouldn't hold your breath.

[YNM]

Theoretically, it can be done. But let's be honest - it's hard to contain light within a place so much that they would start to orbit themselves (which, clasically, might be how a light-based blackhole is). I mean, the energy in each photons are small yet they move fast, so you need to act fast as well, either instantaneously producing so much light at the same time (which is hard) or to ensure in a volume you have some light that comparatively leaves the site slow enough - you'd need light-minutes or something. And just many enough light.

Yeah, better to sip water off every object in a galaxy and collect them in one place - instant supermassive blackhole !

(I know that's insanely hard but the point is the thing would be harder than something insanely hard.)

Edited July 18, 2016 by YNM

[PB666]

20 minutes ago, Snark said:

Several problems you're going to run into, which revolve around the fact that you need really insane densities to get a black hole to form, and that's a very hard thing to do with light.

Start with the fact that light has wavelength of a finite size, and can't be focused smaller than that.  (That's why we have to use electron microscopes to see details on objects smaller than a few microns in size.  Light is just too big.)  So you can't, for example, use visible light to form a black hole  only (say) one nanometer across, because light has a wavelength of several hundred nanometers.

Therefore, that puts an effective minimum size for the black hole of, say, around one micron across.  Let's say a Schwartzchild radius of 500 nanometers.  If I'm doing my math correctly, that would translate to a mass of around 3.3e20 kilograms, i.e. 330 quadrillion metric tons.

As pure energy, in the form of light.  Focused into a pulse  that would have to be no more than about 1.7e-15 seconds in duration, i.e. one 600,000th of a nanosecond.  The needed power would be 1.8e52 watts.

Just to put things into perspective:  The total energy output of our sun is, IIRC, around 3.8e26 watts.

So all you're asking is to generate an energy pulse equivalent to 48 trillion trillion times the power output of our sun-- or, if you prefer, 3.6 quadrillion times the combined power output of the entire Milky Way galaxy.

Or, put another way:  imagine you had a magic capacitor in which you could store up all the energy you want, then release it instantaneously.  Charging up that capacitor with enough energy to create one of these micron-sized black holes would require capturing the entire energy output of our sun for over 2500 years, in order to release it in one 600,000th of a nanosecond.

That seems like... ah, how to put this kindly ... a bit of a tall order.

So I wouldn't hold your breath.

Or to place it otherwise, imagine if you were using solar panels to do this and you had them around stars collecting energy you would need to use a significant number of stars in the visible universe to collect enough one power in one moment to send the pulse.

Imagine if the total amount of laser power you can produce in a moment is GW per meter/2  then you would need 1.8e43 meters cubed. 4piR^2 is the surface area of a sphere = 1.8e43 r=  (5.65 e43)^1/2  

r = 7.5e+21

in light years (9.461e15) = 782169

This is to state that if you had batteries sufficient to power 1 GW/sq.meter lasers at a wavelentgh of visible light for a second, then you would need a shell of lasers pointing at a center with a radius of ~800,000 light years.

That is approximately many times the volume of the milky way galaxy. If we ignore the power requirements and only look at the space requirements and only look at the space-time requirements, and the power density. There is no point in the known universe where this could be done. It would be silly, it would be like building a bridge to the moon to get a better view of an anthill on the other side of the earth. It would take time, at least 1.6 million years to do, and it would take the technology (or something comparable) that one was attempting to build to create a foundation to complete the task. The laser power density is generous. The current energy production of the earth is about 2500 GW which means for the Earth surface (6400 r). The earths current electrical output is 1/51,550,000,000 th of what it would need to be to be a power source. Alternatively you would need a battery capable of storing 51552611369 seconds of power to produce on Gj, againt batteries cannot be counted on to deliver as sizable amount of power in 1/600,000th of a second so the battering would have to be many 100s of times more powerful.

The short answer, its impossible, theoretically plausible but technically impossible.