Stardrives and Spinoza by Louis Crane

Louis Crane

Essay Abstract

We discuss a proposal to make small artificial black holes (ABH's) using a huge laser. Because of Hawking radiation, they would be extremely powerful energy sources. We investigate the technical problems of using them to make power plants and starships. The first suggestion is due to Hawking. Next, we consider what challenges the ABH proposal would pose for a future quantum theory of gravity. The form of a theory which would allow us to compute the necessary corrections to classical theory is considered. It is widely believed that every black hole produces a new baby universe on the other side of its singularity. If this is true, ABH technology will involve future humanity in the creation process of universes. Finally, we ponder the effects that the ABH proposal would have on the culture of a future society, particularly if the baby universe theory is correct. The changes in our economic life and understanding of our role in the cosmos would be so profound as to have a "spiritual" aspect.

Author Bio

Louis Crane completed a PhD in Mathematics at the University of Chicago, did a postdoc at the Institute for Advanced Study in Princeton, and was an Assistant Professor at Yale University. He then joined the Mathematics department at Kansas State University, where he has remained to this day, except for visits to Nottingham University, Universite de Paris VII (Diderot), The University of Western Ontario and Instituto Superior Tecnico in Lisboa, Portugal. His research is on quantum gravity.

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[deleted]

A mere 1 kg mass equivalent of photons is 21.48 megatons. A 1 kg black hole has a lifetime of 2.80x10^(-17) seconds, m^3/3K, K = (hc^4)/(30720)(pi)^2G^2.. What modality can usefully manipulate an object over 30 attoseconds? Given typically less than 10% laser efficency plug to emitter, yer gonna need minimum ~250 megaton input and 100% utilization efficiency, 5X the Tsar Bomba. This raises a question of removing waste heat to spare your manipulation modality. The National Ignition Facility operates at 0.5% efficiency. It would require 4.3 gigatons energy input at 100% utilization efficiency of laser photons into the black hole. The efficiency of energy transfer from electron beam kinetic energy to photon output is between 0.1 to a few percent for free electron lasers. The best technology has to offer is not nearly good enough to support a hallucination

Said black hole cannot be stabilized by feeding it mass. Light propagates 9 nm over the time interval, conservation of angular momentum will swirl not swallow, a cosmic blast of Hawking radiation will push away anything approaching. If you made it in a diamond and we suspended all laws of physics other than gravitation, it would swallow at most 840,000 carbon atoms for a mass increment of 1.667x10^(-18) grams, extending the black hole's lifetime not a whit. If it instantaneously swallowed a gram of diamond it would live another 0.03 attoseconds.

"lasing mass of order 10^9 tonnes to produce the pulse." No... you need a **100% population inverted** superradiant 10^9 tonne lasing mass with 100% efficiency output conversion to the black hole. Now double it - for half the emission will be in the wrong direction and you do not have orthogonal incidence gamma ray mirrors - no beam steering or focusing, either. "Das ist nicht nur nicht richtig, es ist nicht einmal."

[deleted]

I have some basic problems in understanding the short but essential section "The black hole generator" [p. 4]. Maybe the author can address these.

1. "An advantage of using photons is that, since they are bosons,

there is no Pauli exclusion principle to worry about."

Interesting assertion, but wouldn't for the energies provided by the laser vacuum fluctuations (e.g., pair creation) take over making the Pauli principle absolutely necessary?

2. This question raises another concern ("Since photons have null stress energy just like null dust, a black hole should

form if a large aggregate of photons interacts classically with the gravitational field.") as strong vacuum fluctuations would likely not interact classically with the background gravitational field; at least, due to these fluctuations, there would be an effective energy-stress tensor components vastly different from "null dust".

3. I do not understand the algebra in the third paragraph of the section.

Thanks!

[deleted]

My essay also proposes a Hole generator to create holes in space-time (not black holes). We can create holes in space-time using simple processes like decays, annihilations and inelastic scattering. No nuclear lasers are needed. To prove experimentally the existence of holes I need two atomic clocks: holes are accompanied always by time dilation and length contraction effects. The detection of time dilation effect near the atomic station or collider will be the experimental proof for the vacuum holes. Holes in space-time also can be used for hole teleportation and stardrive technologies.

Leshan

Florin Moldoveanu

Dear Professor Crane,

I see two insurmountable problems to your proposal.

First is the issue of control: it has to be real time with not tolerance for error and even if this is possible in principle, it will never be achieved in practice because there is no room to experiment with different ideas. The main reason Wright brothers were the first to achieve controlled flight is because they found a way to tinker with flying machines in a safe way and did not get killed like so many of the prior people attempting it. If the room for mistakes is zero, then there is no way anyone will get it perfect the very first time just by chance.

Second, you cannot accelerate both the ABH and the spaceship in the same direction because of the conservation of momentum. Maybe you can use an Earth bound laser to accelerate the ABH and the ABH radiation to accelerate the starship. But this does not work on interstellar distances.

[deleted]

Mr. Crane,

Thank you for an interesting essay!

I have a question which is but tangentially related to the ABH topic: could you be so kind as to provide a reference to any paper(s) which would provide an update on your current thinking regarding quantum cosmology, a topic which is of considerable interest to me. Lee Smolin briefly discussed some of his collaboration with you, Carlo Rovelli, Fotini Markopoulou, Chris Isham, and others in 'Three Roads to Quantum Gravity' (pp. 46-48) and in 'The Life of the Cosmos' (pp. 270-275). He has referred to the work as "relational quantum theory" and "topological quantum field theories. " If there are more recent reports on the status of this work I've not seen them. Thank you for any available references.

A successful quantum cosmology hopefully would go far toward resolving some of the deeper issues which you've raised in your current essay. Thanks again.

jcns

Helmut Hansen

Dear Mr. Crane,

the most central problem of making starships is surely the unsolved question

How can we overcome the lightbarrier?

By investigating the question How do Space and Time have to be organized in the case of an invisible ether I came across a geometrical structure which was of archetypal design. I looked very much like a MANDALA. This very beautiful geometrical structure can in fact be read as an extension of the Minkowski diagram.

The space-time-structure related to this archetypal space-time-picture has actually a special feature: The speed of 1/SQRT 2 (0.707 c) seems to be a bifurcation point. At this point the relativistic function splits into two branches. The first part of these two branches is the well-known relativistic function with the speed of light as the ultimate limiting speed. But the second part of the function leads into a branch which is still unknown. Its limiting speed is infinite. I am calling this second branch GOEDELs TRENCH.

If this second branch would really exist then the speed of 1/SQRT 2 (0.707 c) could possibly be a GATE to the stars, because it allows us to reach superluminal speeds.

Further information can be found in the attachment Do Space and Time have an Archetypal Design? See Taming of the One, own post of September 18, 2009

H. Hansen

[deleted]

Mr. Crane,

As an addendum to my previous post, I'm aware of the very brief update to the status of relational quantum theories which Smolin presents in 'The Trouble With Physics' (pp. 317-318), but am looking for other, possibly more detailed, updates if such are available.

It also has not escaped my attention that your current essay here at FQXi is a shorter version of your August 2009 paper, 'Are Black Hole Starships Possible?' ( http://arxiv.org/pdf/0908.1803v1 ). Still, a very interesting essay. Thanks!

jcns

Louis Crane

Uncle Al is correct that the energy involved in our proposal completely dwarfs any hydrogen bomb. This is necessary because the energy requirements for starflight are so huge. He is also correct that a 1 kilogram BH would not last long enough to be useful. In fact, it would be too small to produce anyhow.

He is also correct that the proposal is far betond current technology. However, I do not see a fundamental barrier to doing it in a more advanced technological future.

The only BH's I can see how to make at all are the ones I suggest, with energy contents billions of times greater than a hydrogen bomb. They would be stable for centuries.

But, dear uncle, "fantasy" is such an unkind work. I could live with "dream".

It is an enormously difficult technical program, but it is the only path to the stars. If it can be done at all, it is worth the massive sustained effort of technical development to create it.

Dear Andy,

Moving on, I would like to thank Andy for a thoughtful comment. As far as quantum field theoretic effects are concerned, I agree they would need to be included in a more careful calculation. However, as the concentric shell of gamma radiation shrank, the low lying electron and positron states would become occupied, so further pair creation would be suppressed. The creation operators in the Feynman vertex would have zero eigenvalues.So I dont expect a pressure barrier to form.

My companion paper (reference 1) is only a first exploration. Much more analysis is needed. You raise important questions. By the way, there isnt any algebra in my essay. I interpreted "popular essay" as "no calculations". See

reference 1 for details.

Dear Florin,

I agree tinkering is much nicer. However the plan is to build the hypersonic waverider aircraft from supercomputer calculations, since it is impossible to make a wind tunnel powerful enough. If we can do this now, why not in the far future?

As far as momentum conservation is concerned, the ship would be emitting a very powerful beam of collimated radiation backwards, driving the ship and BH forwards. Its like a photon rocket. Radiation pushes ship, ship pushes BH.

I do not feel up to replying to all contributions. I hope this blog doesnt get overcrowded.

[deleted]

Dr. Crane, Thank you for your quick reply. I like your essay!

[deleted]

Dear Professor Crane,

I have to admit, I made a mistake in the momentum conservation comment and accelerating both the BH and the ship at the same time in the same direction can be done.

Take a classic rocket. The fuel explodes in the exhaust, the gasses come out one way, the rocket and the fuel goes the other. But the fuel is attached to the rocket. This is what you cannot have with an ABH: you cannot touch the BH.

So consider now an ABH and a starship. The BH emits lots of radiation, but it is stationary because it is spherically symmetric. A starship can accelerate being pushed away by this radiation but the BH does not move with the starship because it is not attached to it. How can the starship make the ABH move? By capturing the radiation pushing away the starship and sending it back from behind to the ABH. I was thinking that whatever momentum the starship gained in the capturing process is lost in the reversed process of accelerating the ABH and you get a moving ABH and a stationary starship. But I did not consider the case that only a part of the captured radiation can be used for this purpose and we can manage a synchronous acceleration of both ABH and starship.

Louis Crane

Dear Mr. Smith,

My more recent work in quantum gravity has been focussed on the situation of an isolated region viewed by an external classical observer. The notion of relational geometry then becomes relative to what the observer can see. This is motivated by the Bekenstein bound, but also by the thought that we will need to compute quantum corrections some day for experiments like the one I am proposing. My last few papers on gr-qc are on these lines.

The point Florin made is well taken. If we cant compute things in advance the experiment is unimaginable. The Hawking radiation is from transplanckian modes which are redshifted in exiting, so we are in a region where quantum corrections are important.

Im glad you like the essay.

Louis

Louis Crane

Im a bit sorry if I sounded overwhelmed in my first response. The volume of posts is really not excessive and I think on reflection that a Q&AQ format could be a good thing.

Louis

Louis Crane

I have a few new comments on my proposal.

It seems that Arthur Clarke proposed something similar in his novel "Imperial Earth" ( The description of his drive is vague, and seems to have the Physics wrong). Considering that Clarke predicted communications satellites, the internet, lasers and aquaculture, its some indication the idea has possibilities.

Also, it might be easier to charge the laser with fusion reactors instead of solar power. This was suggested by Malcolm Crowley to me.

As far as heat dissipation goes. there is no reason to think of the laser as solid. It could be a large radially oriented lattice.

Calculations due to Schwinger et. al. indicate the infalling spherical wave wo0uld not emit particle antiparticle pairs until very near the point of gravitational collapse. So that is not much of a worry.

The design I propose is really only an exploration of the concept. If the generator is eventually built, it will surely be much more complex.

Terry Padden

Louis

A well written and for me a very welcome essay that, as opposed to the ultimately pessimistic, nihilistic "Dreams of a Final Theory" and TOE nonsense, you provide us with "Dreams of a New Technology" based on possible new physics. Your dream has, as you make clear, a very optimistic message. Moreover, again unlike the TOE stuff, advocates of new technology based on new not quite solid science have often succeeded.

I do think your conclusion is more than optimistic. You have gone over the rainbow and left human nature behind. Only in OZ does your sociology work in a nice way. In particular you write

1. "If the meduso-anthropic hypothesis turns out to be valid, the builders would understand their work as part of the eternal recreation of the universe ..." No way. A few dreamers may think like that; most of us will understand it as a great way to pay the bills and bring up a family.

2. and "So possibly the quantum theory of gravity will give us the tools to reach the stars, solve our energy problem forever, teach us we really have purpose in the cosmos, and COMPEL US to organize ourselves around a common purpose which extends beyond ourselves." Somehow whenever people dream of a Utopia the word COMPEL often seems to come up - My Utopia for everyone, whether they want it or not. There is not much difference between monolithic Utopias and Gulag Archipelagos - except maybe topologically.

Of course I think BH's are mathematical delusions (see my comment and the quote from Abhay Ashtekar on the Jacobson & Sotiriou essay page). My essay has a lot more to say about irrational physics and delusional maths. A mathematicians's comments would be most welcome, even if you have lapsed and sold your soul to QG and fallen into the clutches of Category Theorists..

Jayakar Joseph

Dear Louis Crane,

BH is a mathematical and observational representation in that there is no information receivable by the observer, whereas the observer can receive information from outside of it from event horizon onwards when the observer is out of it. In this context I think, ABM is only an observational representation of artificially created temporal events and have no practical importance. Anyhow the Screening and Antiscreening behavior in QED described by asymptotic freedom on gauge theories is the representation of micro BH in quantum level that I would like to call it as QBH. As BH is the space of void, the asymptotic freedom in QCD is representational for quantum gravity and from this QBH we can start our trip to stars. If we are lucky enough we can reach a star path spontaneously, whereas the source QBH collate with the destination BH, via collation with smaller BH, bigger BH, massive BH and so on. But we cannot drive through selective paths and thereby 'stardrive' is not possible. For selective path drive, the temporal collation events of nature to be interrupted and to be on selective sequential paths starting from quantum level to continuum up to the target and that may need enormous energy in each event of selective collation; is it possible?.

As the energy requirement for this selective path leaps are negative energies, the 'stardrive' cannot be explainable in a Coherent-dynamic cluster-matter universe model, in that the cyclic cluster-matters have only positive energy for their cyclic action. Thereby the 'stardrive' is not possible in this model as it violates the cyclic coherency architecture of it.

With best wishes,

Jayakar

Louis Crane

Dear Terry,

I dont think history bears out your attitude to social behavior at all. Most of history is dominated by religion and religious conflict. People are all too ready to drop immediate practical purposes for some higher goal. Its a fundamental human need. I mentioned the pyramids and the cathedrals.

I think you are confusing necessity with human compulsion. Everything we have ever created we have been driven to by nature and necessity. If I am correct, this is the only way to the stars, and achieving the creation of the ABH technology will be a watershed for the human future. We can go on paying the bills without it, but it will get harder and harder for future generations as Earth resources progressively degrade. It is in our genes to care about the future.

Notice that you are not even able to insult quantum gravity without lapsing into religious metaphors yourself. "Selling ones soul" only has meaning in a worldview with a transcendental struggle and purpose at its core.

By the way, you catch more flies with honey.

Terry Padden

Louis

Re your final points: It seems, once again, humour does not travel well - especially electronically. No insult was intended. I obviously misread you. My apologies. Perhaps you could loosen up just a little.

Here is not really the place for us to argue interpretations of history and sociology, but a brief response to your response.

1. RE 1st Para: I agree that most of history is dominated by conflict, but I consider it simplistic and naive to blame it on religion. People are ready for conflict anywhere anytime. Read the newspaper (or reflect on our interaction). Most conflicts stem from extremely low principled goals; not high ones like a faith in something. Mostly they are about coveting thy neighbours ox, or disagreeing with his opinion, or not liking his behaviour - especially the look on his face. Not to mention sex. The big ones are about power.

There are all kinds of belief systems. Which ones are considered religious and which one are not is subjective. My own approach is to distinguish belief systems from power structures. Sometimes they interact and are superposed in some individuals, but usually it is the Power factor that is determinant, not the Faith one.

The American Civil War was the first one in which modern technology was effectively deployed, and the scale of slaughter compared to all previous conflicts was unparalleled. What was the role of Religion in that conflict, or the major ones of the 20th Century ? They were conflicts over power structures, e.g. a Union v a Confederacy. The desire for Power over others (an OCD ?) is the hidden variable you overlook. That is something rooted in human nature, not particular religions. Even some irreligious - but power crazed - people/groups have caused the odd bit of damage in history. Using the distinction one can have a productive discussion about history. You don't use it.

2. RE 2nd Para: You missed my point, as your use of the Pyramids as an example shows. Do you think those building them enjoyed being slaves ? That example is straight out of "Brave New World", another Utopia. The USSR created lots of things (Sputniks etc.). Is that the kind of "we" you envisage ? It was a Power Structure (not a religion) in which necessity derived from compulsion. There are others equally heinous that we all know about. Your key words are "IF I am correct ..." I hope you have loosened up enough to understand the Power of "IF".

Have a nice day ! (I hope that travels well)

PS It is a good essay; but have you seen "Some like it Hot" ?. Remember the closing shot ?

Jayakar Joseph

Dear Louis Crane,

There is a descriptive error in my posting on, Oct. 13, 2009 @ 13:49 GMT:

'Anyhow the Screening and Antiscreening behavior in QED described by asymptotic freedom on gauge theories is the representation of micro BH in quantum level that I would like to call it as QBH', is to be as:

'Anyhow the Screening and Antiscreening behavior in QED, described from asymptotic freedom in QCD on gauge theories is the representation of micro BH in quantum level that I would like to call it as QBH'.

Regretting for the inconvenience.

Yours jayakar

[deleted]

Congratulation to the winner.

Admittedly, it was the judgment of jury that made me curious. When I read only the abstract some time ago, I looked in vain for the word Spinoza. Having read the essay now, I am disappointed that Spinoza is does mention Spinoza just once and not at all for any of his may very prudent insights but for his pantheism.

Spinoza was certainly correct when he denied atomism and indivisibles in mathematics. He declared it absurd to claim that bodies are composed from areas, areas are composed from lines, and lines are composed from points.

As Spinoza objected to the act of creation, he would perhaps object to the idea of a single big bang.

I do not consider sensational and even religiously colored wild speculations genuine contributions to foundational questions. Maybe, they are nonetheless valuable because they challenge us to ask for hidden flaws in the most basic logic behind possible fallacies. My favorite focus is on the notion singularity.

If I am correct, then the function 1/(x-1), i.e. with a pole, has the value -oo for x=0.999..., which means the limit from the left to x=1, and the value +oo for x-->1 from x>1 with x in IR.

The basis for this remedy is my insight that a number dos not denote a single point and also not the unquantifiable sauce of uncountably much of rather than infinitely many points, but it denotes a measure alias two points on a line. Simply speaking numbers denote the distance between two points with respect to a given unit one. Is there really a measure exactly at x=1? No. There are two different measures, one from the left and one from the right. Buridan's donkey cannot suffer starvation if we use prudent mathematics.

Sorry for killing fireplace romantics.

Eckard