Black Hole Drive Could Power Future Starships

by Ryan Anderson on November 19, 2009

Image credit: NASA

Image credit: NASA



What would happen if humans could deliberately create a blackhole? Well, for starters we might just unlock the ultimate energy source to create the ultimate spacecraft engine — a potential  “black hole-drive” –  to propel ships to the stars.

It turns out black holes are not black at all; they give off “Hawking radiation” that causes them to lose energy (and therefore mass) over time. For large black holes, the amount of radiation produced is miniscule, but very small black holes rapidly turn their mass into a huge amount of energy.

This fact prompted Lois Crane and Shawn Westmoreland of Kansas State University to calculate what it would take to create a small black hole and harness the energy to propel a starship. They found that there is a “sweet spot” for black holes that are small enough to be artificially created and to produce enormous amounts of energy, but are large enough that they don’t immediately evaporate in a burst of particles. Their ideal black hole would have a mass of about a million metric tons and would be about one one-thousandth the size of a proton.

To create such a black hole, Crane and Westmoreland envision a massive spherical gamma-ray laser in space, powered by thousands of square kilometers of solar panels. After charging for a few years, this laser would release the pent-up energy equivalent to a million metric tons of mass in a converging spherical shell of photons. As the shell collapses in on itself, the energy becomes so dense that its own gravity focuses it down to a single point and a black hole is born.

The black hole would immediately begin to disgorge all the energy that was compressed to form it. To harness that energy and propel a starship, the black hole would be placed at the center of a parabolic electron-gas mirror that would reflect all the energy radiated from the black hole out the back of the ship, propelling the ship forward. Particle beams attached to the ship behind the black hole would be used to simultaneously feed the black hole and propel it along with the ship.

Such a black hole drive could easily accelerate to near the speed of light, opening up the cosmos to human travelers, but that’s just the beginning. The micro-black hole could also be used as a power generator capable of transforming any matter directly into energy. This energy could be used to create new black holes and new power generators. Obviously, creating and harnessing black holes is not an easy undertaking, but Crane and Westmoreland point out that the black hole drive has a significant advantage over more speculative technologies like warp drives and wormholes: it is physically possible. And, they believe, worth pursuing “because it allows a completely different and vastly wider destiny for the human race. We should not underestimate the ingenuity of the engineers of the future.”

Article available on ArXiv.
Nod to: io9

Tagged as: black hole, spaceship

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  • dpig69

    This reminds me of the movie “Quest for Fire” and the parallels between humans creating and harnessing fire in the past, to similar challenges for humans creating and harnessing black holes in the future. The last paragraph of this article touched on the possibility of micro-black holes creating new black holes, similar to how early humans kept a “pilot light” going once they first captured fire. On an evolutionary scale, chemical rockets are only a slight variant of man’s early burning log. So we’ve got a long way to go.

  • Olaf

    Hmm I wonder, this ship should also accelerate that million metric tons black hole. It might be tiny but it still weighs that much do can enough energy be created to accelerate the ship and the black hole?

  • Sili

    Sligt problem as I see it.

    Now you don’t just have to accelerate your payload effectively. You’re also carrying “about a million metric tons” of dead weight.

  • http://martianchronicles.wordpress.com Ryan Anderson

    Olaf: Yes, the black hole produces enough energy to accelerate both the ship and itself to relativistic speeds. Check out the ArXiv paper for more info (linked at the bottom of the post).

  • Sili

    D’oh. Shoulda updated. Now I look like a rip-off.

  • Lawrence B. Crowell

    I actually read Crane’s paper on this. There is a bit of a rub with the idea. You can’t focus light rays onto a point with a temperature higher than the source. This is Fermat’s theorem, and it has to do with the conservation of phase space volume for systems in classical mechanics. From a wave mechanics perspective, it means you can’t concentrate an energy flux larger than c*hbar/wavelength. Here c = speed of light, hbar = Planck unit of action.

    Now their scheme involves taking light energy from enormous solar panels and concentrating it into gamma rays. That is possible, but you still run into the same limitation. Those gamma photons would have to have an energy in the TeV range, or equivalently the pulse need a temperature of about 10^20K. Anything less will concentrate photons with too large a wavelength to do the trick. This means the shell which produces gamma rays would have to be a nearly continuous distribution of LHC energy scale lasers! In fact at a million metric tons, which would be the mass-energy of this grand pulse of gamma rays, this would require over a million billion billion times the beam flux (or imploding wave flux) of gamma rays than what the LHC delivers. This would be one hell of a machine!

    Besides the solar arrays being large, consider the size of the energy storage system. it would have to hold a million metric tons in mass equivalent of energy. Clearly the storage system would be many orders of magnitude larger in mass. Then to pulse it right that energy would have to charge up a Marx bank or something. That would have to be utterly huge to prevent the collosal charge stored up from tearing it apart. Imagine the enormous size of this system! This thing would be the size of Ceres, or something comparable.

    Oh well, I suppose it is not completely out of line with ideas of space elevators. Congress is not going to authorize funding for either any time in the near future.

    LC

  • Don Alexander

    LBC, good points.

    This sounds like classical mega-scale engineering.

    I assume making a BH a lot smaller (a few kg, say) and then somehow trying to feed it directly with matter would probably not work. It would irradiate much faster than you would be able to send stuff over the miniscule event horizon.

  • Spaceriuss

    [I]This reminds me of the movie “Quest for Fire”[/I]

    Well, the ship Event Horizon (1997) had black hole drive :)

  • http://martianchronicles.wordpress.com Ryan Anderson

    LBC: Do you mean Fermi? I don’t think the complaint about filling the phase space applies in this case because photons are bosons; there’s not a problem with them occupying the same quantum state. Also, this is definitely not a “classical” system since black holes are involved.

    The rest of your comments are right on though; this would require engineering on a huge scale!

    Don: Yes, a small black hole would evaporate too fast. There is also the concern with even the
    “sweet spot” black holes that they might be too small to feed! An attometer is a pretty small target for the “feeding beam”. In that case you could still use them for the starship drive, but you would have to just discard them at the end (and get away before they explode!).

  • Bariman43

    The instant I read the title, I thought of the movie Event Horizon. That thought alone almost makes me NOT want a black hole powered ship engine. Almost.

    *remembers the violent and bloody Video Log scene*

    ….Yeah, good luck.

  • ND

    The Romulan birds of prey had something called “artificial quantum singularity.”

  • Lawrence B. Crowell

    Ryan Anderson: No this does not involve Fermi-Dirac statistics, which indicates by the anti-symmetry of the fractional spin state one can put on particle in one state. This is about packing photons not in Hilbert state space, but in configuration space (ordinary space).

    BTW, with the Bose Einstein case of generating a black hole, that is a huge scale up of a problem I have been picking at for a while with fusion. The idea is much the same, but to get tritium nuclei to transition into He by these means. A much more modest idea, but damnedably tough to figure out.

    LC

  • Greg

    The old addage states that you can’t get something for nothing. I think the article oversimplifies the undertaking to produce such a thing by many orders of magnitude. You would need an enormous amount of mass and energy to create this thing and it would need to be precisely coordinated. All the black hole would amount to is simply the concentration of all of this matter into a confined and therfore portable and useable state. The good news is that this is doable. The bad news is that all that exists of the U.S. would be archaeological relics by the time the human race the technology and industrial capablility to scale this up to produce a space shipyard with this propulsion capability.
    On the ligher side it looks like the Romulan propulsion design is going to win out over the Federation Warp drive in the future. Just when we thought the Romulans were a bunch of hapless, feckless thugs.

  • http://www.spaceward.org CrazyEddieBlogger

    Lawrence – I must of course respond to the Space Elevator comment…

    A goos sized SE weighs several thousands tons, and is powered by maybe a Megawatt-class laser beam – hardly a “mega project”.

    Feasible or not – this remains to be seen, but if it is, the launched weight will be less than the ISS.

    Ben

  • http://crowlspace.com/ qraal

    Hi Ryan

    One issue with the drive is whether black holes decay to zero mass or “choke” themselves due to quantum back-reaction, thus only converting about 10% of their mass to energy. Tony Rothman has analysed this possibility recently and there’s nothing astrophysically to preclude the possibility. We’ll need a lot more study of black holes generated by successors of the LHC to tell if this occurs.

    Even so 10% conversion efficiency is nothing to sneeze at and we avoid the “Hawking Explosion” during the last second of a decaying hole.

  • DrFlimmer

    As far as I know, the warp drive is physically possible. The only problem is (but that is a problem for engineers ;) ) that you need to pack 30 solar masses into the Enterprise. I guess this needs to be a black hole ;)

  • Lawrence B. Crowell

    @CrazyEddieBlogger. A space elevator weighing in at a few thousand tons? Given geosychronous orbit is 37,000 km out that would mean an average of about 100kg per kilometer. That is about the mass of two cargo sacks of potatoes. BTW, a few days ago I volunteered at a food bank (very busy these days!) and hauled a whole bunch of them around

    @ Dr Flimmer: The Alcubierre warp drive is a solution to the Einstein field equation. There are a fewf problems though. The solution violates the weak energy condition that the momentum energy component T^{00} >= 0. This means the quantum field which is the source of the solution is not bounded below with a discrete energy spectrum. This is a disaster for physics. Another problem is that any such configuration of spacetime would permit one to enter a black hole, acquire information about its interior and then return to the outside. This would violate the second law of thermodynamics for black holes. Finally, such configurations can be converted to solutions with closed timelike curves, or in other words time machines. There you have causality issues and properly define Cauchy spatial surfaces of data.

    @Graff: There are issues along these lines. The questions are open because metric back reactions are a classical response to a quantum process. Hawking radiation is derived in a semi-classical setting, where the black hole is classical. In what I am working on gravity is not really quantized as such, so as the BH becomes smaller there its radiative processing departs from what might be expected. It is possible that it actually slows down as it reaches the 10^6 Planck units of mass and leaves behinds a remnant which is a topological “knot” in spacetime.

    LC

  • Torbjorn Larsson OM

    What a fascinating idea!

    This is Fermat’s theorem, and it has to do with the conservation of phase space volume for systems in classical mechanics.

    Even if it is one of Fermi’s theorems, it doesn’t say much as a reference.

    More to the point here, BH’s are outside of classical mechanics, so AFAIU all bets are off. What will happen at the transit between classical to BH regime?

    This would violate the second law of thermodynamics for black holes.

    Sorry to pick on the comments, but I don’t get the idea here. Black holes will eventually give back their information to the universe, so why would a worm hole or similar information channel be a problem for them? Wouldn’t they just diminish in surface area (volume) faster?

    This doesn’t save Alcubierre’s drive though. Famously, it depends on the solution (and it’s confined transit volume) being already transiting at supra-light speed at it’s creation. As we can’t get from here to there without the drive, we can’t get from here to there to make the drive! (o.O)

    Causality can be a bitch.

    in other words time machines. There you have causality issues

    Worse; as Scott Aaronson points out time machines would also implode the algorithmic tower of complexity. (Physics with time travel becomes unboundedly algorithmically powerful, or conversely everything is equally easy.) As this isn’t so, they can’t exist.

    Which of course means that FTL drives and communication can’t exist either. No loop holes.

  • http://www.plasmaresources.com/ davesmith_au

    I sure hope Crane and Westmoreland didn’t use taxpayer funds for this trip down fantasy lane…

  • Dark Gnat

    How would you contain the black hole?

    Also, traveling near the speed of light, what happens if you hit a dust particle? (Answer = Boom!)

    Also, wouldn’t radiation thats coming from space in front of you be blue shifted to higher energies?

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