# The Naked Scientists Forum

### Author Topic: Energy problem? What energy problem?  (Read 9434 times)

#### edward2007

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##### Energy problem? What energy problem?
« on: 20/06/2007 11:55:52 »
Find a mini black hole and orbit a satellite around it.
Then you shoot α-particles at the black hole at a rate of 1 per second.
As the particle gets sucked into the BH, lots of high power X-rays radiation results.
Catch that enery your tame BH throws at you, convert it into micro waves and beam to wherever you need it.

What energy problem?

Now you may shoot holes in my theory.

#### daveshorts

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##### Energy problem? What energy problem?
« Reply #1 on: 20/06/2007 12:10:06 »
Most of the problem with this idea would be manufacturing and controlling your mini-black hole. Black holes evaporate. The time it takes a black hole to evaporate is proportional to 1/mass5 which means that below a certain mass they are very unstable, and you would need lots of energy to create one. which you could have used to power your playstation in the first place.

#### DoctorBeaver

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##### Energy problem? What energy problem?
« Reply #2 on: 20/06/2007 12:48:22 »
Plus the energy needed to shoot the α-particles at the BH.

#### Batroost

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##### Energy problem? What energy problem?
« Reply #3 on: 20/06/2007 19:06:20 »
Then there's the problem of how many alpha-particles you're going to need.

For comparison a 1200MW nuclear power station fissions around 1020 atoms of Uranium per second. As you're not converting the alpha particles wholly to x-rays I'm guessing that the energy yields may be comparable.

Oh... and there's the point that only a fraction of the x-rays are going to be captured.

And... what efficiency are you assuming in converting the x-ray energy to microwaves?

#### lightarrow

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##### Energy problem? What energy problem?
« Reply #4 on: 20/06/2007 22:32:54 »
Find a mini black hole and orbit a satellite around it.
Then you shoot α-particles at the black hole at a rate of 1 per second.
As the particle gets sucked into the BH, lots of high power X-rays radiation results.
Catch that enery your tame BH throws at you, convert it into micro waves and beam to wherever you need it.
What energy problem?
Now you may shoot holes in my theory.

Why α particles? We should use it to get rid of garbage and radioactive wastes!

#### Soul Surfer

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##### Energy problem? What energy problem?
« Reply #5 on: 20/06/2007 23:49:29 »
This has been used as source material for several sci fi stories.  You dont have to do that  all you need is the mini black hole!  if you chose on the right size you can get millions of years of energy from it as it evaportates naturally

http://xaonon.dyndns.org/hawking/  This website will give you the correct size for the hole.   The big problem is creating a small black hole!  it takes all the gravitiational enegy in a collapsing star many times the size of the sun to compress material into a stellar mass black hole and the smaller the mass of the hole the higher the energy density you need to create it.  the best way would probably to accelerate a lot of neatly shaped smallish asteroids at near light velocities and get them to collide at a single point in a dynamically balanced collision.  A bit beyond current technology.

#### another_someone

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##### Energy problem? What energy problem?
« Reply #6 on: 21/06/2007 01:17:50 »
This has been used as source material for several sci fi stories.  You dont have to do that  all you need is the mini black hole!  if you chose on the right size you can get millions of years of energy from it as it evaportates naturally

http://xaonon.dyndns.org/hawking/  This website will give you the correct size for the hole.   The big problem is creating a small black hole!  it takes all the gravitiational enegy in a collapsing star many times the size of the sun to compress material into a stellar mass black hole and the smaller the mass of the hole the higher the energy density you need to create it.  the best way would probably to accelerate a lot of neatly shaped smallish asteroids at near light velocities and get them to collide at a single point in a dynamically balanced collision.  A bit beyond current technology.

Assuming that small black holes can persist for any significant period of time, and assuming that black hole can evaporate (in some circumstances, at a rate faster than they are accruing fresh matter), then would one actually need to create a mini-black hole at all - could one not simply wait until a large black hole naturally decays down to the level of a mini black hole (OK, I am not suggesting that the average human being will live long enough to be able to wait out such an event; but maybe we could search for such an event to have taken place in the past, and then go and pick up the residue of such an event).

Yes, I can see lots of problems with this idea (such as, for a black hole not to have accrued more matter, it must be situated far away from any existing matter, including planet Earth, so we might have to travel quite a distance to locate such a relic; and how would we be able to detect such an isolated black hole; and how then would we constrain such a black hole to bring it back home - but then is this really that much more technically challenging than the alternative scenarios?).

#### ukmicky

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##### Energy problem? What energy problem?
« Reply #7 on: 21/06/2007 01:40:04 »
Sorry Edward
Can i apologise, it seems rather than shooting your theory they seem to have blown it to smithereens, bloody scientists. :)

#### Soul Surfer

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##### Energy problem? What energy problem?
« Reply #8 on: 21/06/2007 10:00:20 »
The big problem is that most people do not have the remotest idea of the true scale of things involved with black holes.

The starting conditions for the model I have given above show a "convenient" power generating black hole  with a mass of a thousand million metric tons and Hawking radiation a power output of 300 Megawattts and a working life of more than two thousand million years   It is however about the size of an atomic nucleus!

It is diffcult to realize how cold black holes of any significant size are,  and how long they live before they evaporate in a cold environment.  In a warm environment they just get bigger by absorbing the background radiation.

For a black hole to have a temeperature about equal to the microwave background  ie it is just starting to loose energy and warm up  It weighs about one hundredth the mass of the earth  is about the size of a grain of dust and will last for around 100,000,000,000,000,000,000,000,000,000,000,000 thousand million years before it evaporates if space was totally cold around it.

A solar mass black hole is has a diameter of about three miles a temperature of 6x10^-8 kelvin  and lasts  1x10^67 years.

Also people do not realise how weak they on an astronomical scale are when they evaporate.  A black hole with the brilliance of the sun (not a desperately bright star) only lasts a few nanoseconds.  In the last few seconds or so of their lives they only radiate about as brightly as the faintest stars that we can detect

#### edward2007

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##### Energy problem? What energy problem?
« Reply #9 on: 21/06/2007 13:51:11 »
Sorry Edward
Can i apologise, it seems rather than shooting your theory they seem to have blown it to smithereens, bloody scientists. :)

Yeah, all talk and no imagination.
No wonder their papers are always too flipping boring to read... ;-)

What is the difference between a writer and a scientist?
Both use words, but the scientist just to show off.
The writer really reaches his audience.
« Last Edit: 21/06/2007 14:10:49 by edward2007 »

#### ukmicky

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##### Energy problem? What energy problem?
« Reply #10 on: 21/06/2007 15:10:26 »
Black holes might not exist
Quote
Black holes might not exist – or at least not as scientists have imagined, cloaked by an impenetrable "event horizon". A controversial new calculation could abolish the horizon, and so solve a troubling paradox in physics.

The event horizon is supposed to mark a boundary beyond which nothing can escape a black hole's gravity. According to the general theory of relativity, even light is trapped inside the horizon, and no information about what fell into the hole can ever escape. Information seems to have fallen out of the universe.

That contradicts the equations of quantum mechanics, which always preserve information. How to resolve this conflict?
http://space.newscientist.com/article/dn12089-do-black-holes-really-exist.html

YOU NEED TO READ THE FUL ARTICLE FOR IT TO MAKE SENSE
« Last Edit: 21/06/2007 15:25:34 by ukmicky »

#### DoctorBeaver

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##### Energy problem? What energy problem?
« Reply #11 on: 21/06/2007 15:36:14 »
Interesting article, Micky.

#### ukmicky

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##### Energy problem? What energy problem?
« Reply #12 on: 21/06/2007 15:39:18 »
If it were true i would imagine their would be a lot of astrophysicists looking for something new in their lives :)

#### DoctorBeaver

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##### Energy problem? What energy problem?
« Reply #13 on: 21/06/2007 15:50:39 »
If it were true i would imagine their would be a lot of astrophysicists looking for something new in their lives :)

Like a job, for instance?

#### edward2007

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##### Energy problem? What energy problem?
« Reply #14 on: 22/06/2007 12:10:23 »
Okay, got some spare time to shoot back. (I never said I wouldn't, did I?)

Daveshorts:
<manufacturing and controlling your mini-black hole.>
No need to make a black hole:
In a podcast from NARO I heard an astronomer mention the high probability of the existence of micro black holes, perhaps no further away than just beyond the Oort cloud. They are still looking though, we may have to wait a few years...

<Black holes evaporate.>
Let me see if I understand it:
A black hole is the ultimate miser, it lets out nothing, neither particles nor EM radiation.
Evaporation is the escape of particles to where there is lower entropy.

To me, these two propositions are mutually exclusive.
Either something escapes and it is not a black hole, or nothing escapes and it is a black hole.

DoctorBeaver:
<Plus the energy needed to shoot the α-particles at the BH.>
With the enormous atraction of a BH, I don't think the problem is the expense of energy to shoot the particles. All you need to do is release them, the speed they have emerging from their radioactive matrix should be enough.

Batroost:
<Then there's the problem of how many alpha-particles you're going to need.>
Some sources of α's, I guess a mass of 1 kilo would last a pretty long time...
I am more concerned about (most of) this stuff being strong poisons besides being a little radioactive.
* Americium
* Uranium
* Plutonium-238
* Plutonium-239
* Polonium

<For comparison a 1200MW nuclear power station fissions around 1020 atoms of Uranium per second.>
I think this is irrelevant, I am not talking fission nor atoms.

<As you're not converting the alpha particles wholly to x-rays I'm guessing that the energy yields may be comparable.>
I was unable (up to now) to find the exact amount of that conversion. Most sourses just mention γ and X-rays without quantificatin. Still, in view of the tremendously destructive  forces at play, I think I can safely assume plenty enough energy for us to play with and not mope about a few megawatts getting lost in the process.

<Oh... and there's the point that only a fraction of the x-rays are going to be captured.>
True, but so is Solar energy...

<And... what efficiency are you assuming in converting the x-ray energy to microwaves?>
I have not the foggiest, but that is for you Boffins to improve on. After all, it's all in th EM spectrum so what about those X-ray satellite? Their detectors convert X-rays into ultimately an AC voltage which received here on earth gives the pretty pictures.
As Radio Amateur, I never went into giga and micro territory, because the efficiency of affordable IC's was around 4-10%. (For a schoolboy, forking out £ 300 or more was a big no-no.) Things have improved and I would guess that efficiency rating is now up to 50-60%.
Again, I cannot find data on X-ray satellites.

Lightarrow:
<We should use it to get rid of garbage and radioactive wastes!>
The sun is closer.

Well, so far my return shots. Just one itsie-bitsie-little-tiny sting at the end as revenge:

If scientists are supposed to be very areful and accurate persons, how come you lanch into a debate on the creation of a BH, when I said Find?

« Last Edit: 22/06/2007 12:34:17 by edward2007 »

#### Soul Surfer

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##### Energy problem? What energy problem?
« Reply #15 on: 22/06/2007 16:37:28 »
How then do you propose to find a small black hole?

A power generating one may just be detectable at a few million miles distance but a slightly bigger cold one would be virtually undetectable.  the gravititional effect of the earth is only detectable in the motions of other bodies over a few million miles over a long period of time.

#### Batroost

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##### Energy problem? What energy problem?
« Reply #16 on: 22/06/2007 17:26:39 »

Quote
<Black holes evaporate.>
Let me see if I understand it:
A black hole is the ultimate miser, it lets out nothing, neither particles nor EM radiation.
Evaporation is the escape of particles to where there is lower entropy.

To me, these two propositions are mutually exclusive.
Either something escapes and it is not a black hole, or nothing escapes and it is a black hole.

I think the theory relies on the continuous creation of short-lived virtual particle pairs - something predicted by quantum mechanics. When pairs are produced close to a Black-Hole's event horizon occasionally one of the pair will fall-in and one escape. I believe the theory suggests that these orphaned virtual particles then survive at the expense of the Black-Hole's Energy/Mass. Perhaps evaporation isn't the most helpful name for the mechanism...?

Quote
<Then there's the problem of how many alpha-particles you're going to need.>
Some sources of α's, I guess a mass of 1 kilo would last a pretty long time...
I am more concerned about (most of) this stuff being strong poisons besides being a little radioactive.
* Americium
* Uranium
* Plutonium-238
* Plutonium-239
* Polonium

<For comparison a 1200MW nuclear power station fissions around 1020 atoms of Uranium per second.>
I think this is irrelevant, I am not talking fission nor atoms.

No - think a bit more carefully about this. The numbers matter here. 1kg of the materials you mention is of the order of 1024 atoms i.e. a few Moles at most. But it's the half life (for alpha decay) that determines how many alpha particles you are going to get in a unit of time. Ignoring the fact that you've included Pu-238 (where do you get that from...?) let's take Pu-239 as an example. It has a half-life of 24,000 years so in a second (i.e. 10-12 of a half-life) you're only going to see (very roughly) about 1012 alphas from 1kg of Pu-239 - incidentally in random directions. The mass equivalent of an alpha particle is about 3700 MeV or roughly 20 times the energy you get from one Uranium fission (200MeV), if the alpha was completely converted to energy - and that seems optimistic. The upshot is that if you converted all the alphas from 1kg of Pu-239 completely to energy you'd be generating (on average) 240 Watts!!! Enough for a couple of light bulbs...

Of course you could use an alpha emitter with a shorter half-life - but how much energy are you going to use in producing it?

Quote
have not the foggiest, but that is for you Boffins to improve on. After all, it's all in th EM spectrum so what about those X-ray satellite? Their detectors convert X-rays into ultimately an AC voltage which received here on earth gives the pretty pictures.
As Radio Amateur, I never went into giga and micro territory, because the efficiency of affordable IC's was around 4-10%. (For a schoolboy, forking out £ 300 or more was a big no-no.) Things have improved and I would guess that efficiency rating is now up to 50-60%.
Again, I cannot find data on X-ray satellites.

You're first problem here is directionality. Unless you completely surround the black hole with your capturing medium you are only going to capture that fraction of your x-rays entering the 'solid-angle' your medium does occupy. And some of your X-rays will go straight through.

Secondly I can't think of any material that converts EM radiation into electricity at an efficiency greater than say 30% - perhaps someone else knows of one.

Quote
Lightarrow:
<We should use it to get rid of garbage and radioactive wastes!>
The sun is closer.

Yes it is. But first you'll have to convince people it is safe to put this radioactive waste on a rocket.

Have fun,

Batroost

#### edward2007

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##### Energy problem? What energy problem?
« Reply #17 on: 23/06/2007 11:41:19 »
<I believe the theory suggests that these orphaned virtual particles then survive at the expense of the Black-Hole's Energy/Mass.>
You just lost me there but I'll accept it as only theory. Seems theory and real world don't meet for a non physisist... ;-)

I thought I had. Simple thinking, perhaps too simple...  I am trying to understand the calculation but my field is medical chemistry. Physics was way back when...

<The upshot is that if you converted all the alphas from 1kg of Pu-239 completely to energy you'd be generating (on average) 240 Watts!!! Enough for a couple of light bulbs...>
But I', not converting the alphas, I want to shoot them at a BH and then catch the resultant flare energy. I could trow rockes at the sucker, but that would result in enormous flares of X-ray energy, if I hear astronomers talking? Too dangerous then.

#### jolly

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##### Energy problem? What energy problem?
« Reply #18 on: 23/06/2007 21:28:47 »
<I believe the theory suggests that these orphaned virtual particles then survive at the expense of the Black-Hole's Energy/Mass.>
You just lost me there but I'll accept it as only theory. Seems theory and real world don't meet for a non physisist... ;-)

I thought I had. Simple thinking, perhaps too simple...  I am trying to understand the calculation but my field is medical chemistry. Physics was way back when...

<The upshot is that if you converted all the alphas from 1kg of Pu-239 completely to energy you'd be generating (on average) 240 Watts!!! Enough for a couple of light bulbs...>
But I', not converting the alphas, I want to shoot them at a BH and then catch the resultant flare energy. I could trow rockes at the sucker, but that would result in enormous flares of X-ray energy, if I hear astronomers talking? Too dangerous then.

Yeah its very dangerous. Your not making one 4 starters! So you´ll have to find one then go there with all the equipment to do it, and hope you dont get sucked in setting it up. Then you have to consider if your particals will affect the BH- You dont know is the answer.

#### Soul Surfer

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##### Energy problem? What energy problem?
« Reply #19 on: 23/06/2007 23:41:26 »
You have your physics all wrong. If you were to shoot individual particles into a black hole they would vanish without a trace.  There is no reason for any flare of energy however if you were to throw a lage chunk of matter at quite a big black hole It would probably go into orbit around it get disrupted by the tidal forces and then get extremely hot before it fell in the hole.  This is probably what is happening with quasars and active galactic nucleii.

It is an interesting thought about what a small cool black hole would do for example using the black hole properties model in

http://xaonon.dyndns.org/hawking/

a room temperature (300deg K) black hole  is around 600 nanometeres across  and weighs around one ten thousanth of the mass of the earth  one earth mass has a 1g gravitiational field  at a diameter of 10,000km  so for one ten thousanth the vmass it would be one hundredthy the distance so it would have a 1 g field around 100 km away..

The hot hole that was the size of a neucleus I mentioned earlier would have a 1g field about 10 metres away from itslf

#### Batroost

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##### Energy problem? What energy problem?
« Reply #20 on: 25/06/2007 19:47:38 »
Quote
You have your physics all wrong. If you were to shoot individual particles into a black hole they would vanish without a trace.

Bremsstrahlung?

#### Soul Surfer

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##### Energy problem? What energy problem?
« Reply #21 on: 26/06/2007 00:02:46 »
Bremsstrahlung  implies the presence of other material if there is a vacuum around the hole and you sling particles there a few at a time nothing much happens.  you have to have a lot of material rubbing against each other and trying to loose angular momentum to get into the hole to get any significant output

#### syhprum

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##### Energy problem? What energy problem?
« Reply #22 on: 26/06/2007 10:28:13 »
Although I agree that multiple collisions between particles rotating around a black hole will produce heating and consequent radiation this is not what I understand as Bremsstrahlung radiation.
Surely this is radiation produced when particles move thru a medium at a greater speed than the speed of light in that medium ( a sort of sound barrier breaking type phenomena ).

« Last Edit: 29/06/2007 11:33:29 by syhprum »

#### edward2007

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##### Energy problem? What energy problem?
« Reply #23 on: 26/06/2007 11:17:01 »
<You have your physics all wrong.>
Granted, but I am a writer, not a physisist. I have to go by the info you boffins publish, like:

http://3quarksdaily.blogs.com/3quarksdaily/2005/04/physicists_coul.html

http://cerncourier.com/cws/article/cern/29199

So, if I misinterpreted it, maybe it was not clearly enough explained for the layman?

<If you were to shoot individual particles into a black hole they would vanish without a trace.>
Oh, and those pics that show giant jets of gas being expelled then?
http://www.space.com/scienceastronomy/astronomy/our_black_hole_000920.html (scroll down a bit)

#### Batroost

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##### Energy problem? What energy problem?
« Reply #24 on: 26/06/2007 20:06:54 »
Quote
Although I agree that multiple collisions between particles rotating around a black hole will produce heating and consequent radiation this is not what I understand as Bremsstrahlung radiation.
Surely this is radiation produced when particles move thru a medium at a greater speed than the speed of light in that medium ( a sort of sound breaking breaking type phenomena ).