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Now this is what I call engineering. They talk about 160 Petawatts in an off-hand, nonchalant way (and that is from one black hole).

For comparison, that's only slightly less than the total sunlight incident on the Earth (174 Petawatts, about 90 Petawatts hits the surface). 174 Petawatts is equivalent to less than 2kg mass - two bags of sugar, for over 100 times the world energy use in 2008 (15 Terawatts).

And yet we have people talking about wind turbines as a viable source of power. That's pitiful.

If you are getting depressed about the way the world is going, spend a little time at nextbigfuture.com, if you don't find something there to make you go wow!, then you're already dead! :)

Are Black Hole Starships Possible? (20 page pdf) By Louis Crane and Shawn Westmoreland, Kansas State University (H/T Crowlspace)

 

The purpose of this paper is to investigate whether it is possible to build artificial Black holes of the appropriate size, and to employ them in powerplants and starships. The conclusion we reach is that it is just on the edge of possibility to do so, but that quantum gravity effects, as yet unknown, could change the picture either way.

We discuss designs for a family of machines which would in combination realize our program. The machines are far beyond current technological capabilities. The Black hole generator would be a gamma ray laser with a lasing mass of order one billion tonnes.

Other than black hole radiation, which we study below, the only process we
know of which is sufficiently energetic is matter-antimatter annihilation. This
has been proposed, but there are two severe obstacles.

The first is that the efficiency of antimatter production in current accelerators is well below 10^−7 (very few collisions produce a trappable antiparticle). Thus, making enough antimatter to propel a starship would use up ten million times as much energy as our proposal. The most optimistic projections of antimatter enthusiasts do not produce an efficiency above 10^−4, so that at best our proposal is still ten thousand times more efficient.

Make the Right Black Hole

 

List of criteria: We need a black hole which

1. has a long enough lifespan to be useful,
2. is powerful enough to accelerate itself up to a reasonable fraction of the speed
of light in a reasonable amount of time,
3. is small enough that we can access the energy to make it,
4. is large enough that we can focus the energy to make it,
5. has mass comparable to a starship.

A black hole with a radius of a few attometers at least roughly meets the list of criteria. Such BHs would have mass of the order of 1,000,000 tonnes, and lifetimes ranging from decades to centuries. A high-efficiency square solar panel a few hundred km on each side, in a circular orbit about the sun at a distance of 1,000,000 km, would absorb enough energy in a year to produce one such BH. The family of BH solutions has a “sweet spot.”

Four Machines for Implementation

These devices are far beyond current technology, but we think they are possibly capable of being implemented ultimately if a future industrial society were determined to do so.

1. The black hole generator

A SBH (Schwarzschild Black Hole in a quiescent steady state) could be artificially created by firing a huge number of gamma rays from a spherically converging laser. The idea is to pack so much energy into such a small space that a BH will form. An advantage of using photons is that, since they are bosons, there is no Pauli exclusion principle to worry about. Although a laserpowered black hole generator presents huge engineering challenges, the concept appears to be physically sound according to classical general relativity.

A nuclear laser can convert on the order of 10^−3 of its rest mass to radiation, we would need a lasing mass of order one billion to produce the pulse. This should correspond to a mass of order 10 billion tonnes for the whole structure (the size of a small asteroid). Such a structure would be assembled in space near the sun by an army of robots and built out of space-based materials.

2. The drive

For a SBH to drive a starship. We need to accomplish 3 things.
Design requirements for a BH starship
1. use the Hawking radiation to drive the vessel
2. drive the BH at the same acceleration
3. feed the BH to maintain its temperature

Item 3 is not absolutely necessary. We could manufacture a SBH, use it to drive a ship one way, and release the remnant at the destination. However this would limit us greatly as to performance, and be very disappointing in the powerplant application discussed below.

The most optimistic approach is to solve requirements 2 and 3 together by attaching particle beams to the body of the ship behind the BH and beaming in matter. This would both accelerate the SBH, since BHs “move when you push them” and add mass to the SBH, extending the lifetime.

3. The powerplant
This has already been proposed by Hawking. We simply surround the SBH with a spherical shield, and use it to drive heat engines. (Or possibly use gamma ray solar cells, if such things be.) This would have an enormous advantage over solar electric power in that the energy would be dense and hence cheaper to accumulate.

The 3 machines here really form a tool set. Without the drive, getting the powerplant near Earth where we need it would be very difficult. Without the generator, it would require the good fortune to find a primordial SBH to implement the proposal.

4. The self-driven generator

The industry formed by our first 3 machines would not yet be really mature. To fully tap the possibilities we would need a fourth machine, a generator coupled to a family of SBHs which could be used to charge its laser. Assuming we can feed a SBH as discussed above, we would then have a perpetual source of SBHs, which could run indefinitely on water or dust or whatever matter was most convenient.

A civilization equipped with our four machine tool set would be almost unimaginably energy rich. It could settle the galaxy at will.

What BHs are long-lived enough and powerful enough for interstellar
travel?

SBHs of radii less than 1 attometer are incredibly powerful. Note however that the life expectancy of a BH with a radius of 0.16 attometers is less than about 2 weeks. In order for such a BH to last significantly longer than that, an external agent must force-feed it mass-energy at a rate of many kilograms per second. As we have emphasized throughout the text, It is unknown whether SBHs, since they are so very small, can feed on anything at all, let alone many kilograms per second. If SBHs with radii on the order of 0.1 attometers could be force-fed at sufficiently high rates, by using a feeding system whose mass is small compared to the mass of the SBH, then it is not hard to believe that such SBHs could be very useful as power sources for starship propulsion systems - if their power can be harnessed efficiently. In the following however, we will assume that SBHs cannot be fed. Even in this “worst case scenario,” it turns out that SBHs could still turn out to be useful for interstellar travel.

We note that guiding a BH is less difficult than feeding it, because it is only necessary to scatter radiation off the BH to impart momentum to it. If even this is impossible, it is hard to see how to build any drive at all. About the fastest type of interstellar voyage that human beings could physically tolerate would be a one-way trip from Earth to Alpha Centauri (a distance of just over 4 light years) which accelerates at a proper acceleration of 1 g for the first half of the voyage and decelerates at 1 g for the second half. In this way, the travelers arrive at Alpha Centauri with zero relative speed. The trip would only take about 3.5 years from the perspective of the travelers (thanks to Special Relativity).

A BH with a life expectancy of about 3.5 years has a radius of about 0.9 attometers. Unless SBH lifetimes can be significantly extended via feeding, a manned interstellar vehicle powered by an on-board SBH requires SBHs of at least this initial size (and most likely quite larger). Conceivably, unfed SBHs of radii less than 0.9 attometers, having less than 3.5 year life expectancies, could be used to rapidly accelerate interstellar robotic probes to relativistic speeds. Robotic probes do not necessarily need to “stop” and could tolerate much larger accelerations than humans. The problem of navigating such objects could be difficult however.

The SBH would have to be ejected (or otherwise escaped from) before it explodes.

A SBH with a radius of 0.9 attometers has a mass of about 606,000 tonnes and a power output of about 160 petawatts. Over a period of only 20 days a 160 petawatt power source emits enough energy to accelerate 606,000 tonnes up to about 10% the speed of light. Of course, it is unrealistic to suppose that the emitted energy can be converted into kinetic energy with 100% efficiency, but even if the conversion occurs with an efficiency of only 10%, it only takes 10 times longer to deliver the requisite kinetic energy.

 

Decontamination, rain and the passage of time have washed off much of the radioactive grime that coated Chernobyl, though plutonium has a half-life of 25,000 years. What didn't blow away has sunk into the soil, been absorbed by plants, in turn eaten by animals, and moved on up the food chain to be part of the biological continuum.

Yet this most blighted part of the planet is so very far from a dead zone these days. With humans withdrawing, animals roam at will and the plant life is more dramatic, even if some trees have sprung strangely. As one researcher put it: "Those trees have a terrible time knowing which way is up."

Few predicted this kind of resurgence in so short a span of time. It's all still contaminated but it's abundant in the absence of human habitation, reinforcing the belief that the greatest threat to nature is man. Left to its own devices, nature finds a way to survive and thrive.

A fascinating return to the scene of the worst nuclear disaster in history: the Chernobyl "Exclusion Zone". And there's been a surprising resurgence of wildlife and green stuff even amongst the radioactive contamination. Like kooky old Jeff Goldblum said in Jurassic Park: "Life, uh, finds a way..."

People think differently under controlled conditions.

Clumsy Solutions for a Complex World is a powerful and original statement on why well-intended attempts to alleviate pressing social ills too often derail, and how effective, efficient and broadly acceptable solutions to social problems can be found. It takes its cue from the idea that our endlessly changing and complex social worlds consist of ceaseless interactions between organizing, justifying and perceiving social relations. Each time one of these perspectives is excluded from collective decision-making, governance failure inevitably results. Successful solutions are therefore creative combinations of four opposing ways of organizing and thinking. This book, jointly written by leading political scientists, anthropologists, economists, lawyers, sociologists, a geographer and an engineer, shows the force of these theoretically sophisticated, yet simple and practical ideas for a number of pressing issues from around the globe.

Why the FUCK is the book £56.00? To keep the plebs from reading it? Twats.

First in a series of factual booklets describing nuclear power issues for the layman. The author, Dr Colin Keay, is a retired physicist, who advocates a scientific approach to the issues of nuclear power and endorses nuclear energy to save the environment.

Second in a series of factual booklets describing nuclear power issues for the layman. The author, Dr Colin Keay, is a retired physicist, who advocates a scientific approach to the issues of nuclear power and endorses nuclear energy to save the environment.