Sep 22, 2012

Debunking the Black Hole Interstellar Drive

Posted by in categories: business, engineering, fun, physics, policy, space

Louis Crane and Shawn Westmoreland co-authored the paper Are Black Hole Starships Possible? ( that suggested that one could use Small Black Holes to propel starships close to the velocity of light for interstellar travel. To give them credit, they stated that this is at the “edge of possibility” and would only be possible in the very distant future:

“The purpose of this paper is to investigate whether it is possible to build artificial BHs 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… Many questions which arise in this program lead to calculations in general relativity which have not been done. Whatever the other merits of our proposal, we are confident it will pose many interesting problems for classical and quantum relativity.”

Note, BH = Black Holes

That is it. Crane & Westmoreland were presenting an academic exercise to pose “many interesting problems for classical and quantum relativity”.

However, others like James Messig and Paul Gilster and Marcus Chown have taken this to mean a real engineering problem that can be solved . . . Read their articles.

I only found out about Marcus Chown because Paul Gilster says “Chown does a good job with this material” quotes him, and I reproduce here,

“The resulting million-tonne black hole would be about the size of an atomic nucleus. The next step would be to manoeuvre it into the focal range of a parabolic mirror attached to the back of the crew quarters of a starship. Hawking radiation consists of all sorts of species of subatomic particles, but the most common will be gamma ray photons. Collimated into a parallel beam by the parabolic mirror, these would be the starship’s exhaust and would push it forward.”

What a parabolic mirror … with black holes in the same paragraph? This I must see. I traced Marcus Chown comments to his article Riding a black hole to reach the stars. Chown actually states this paragraph above.

Here are the problems with Marcus Chown statement & Paul Gilster’s unquestioning nod of authority to Chown’s statement.

1. How do you control a black how?
Small Black Hole radius = 0.6 × 10-18 m, in comparison assuming a spherical shape (Illinois University), the typical space between particles in the gas is 2×10-9 m, and the average distance between two bonded atoms in water is 2X10-10 m, and generally speaking the space between two bonded atoms is around 10-10 m. That is one can fit 108 or 100 million Small Black Holes between two atoms in an average chemical compound.

So how does one control a 1,000,000 ton black hole that is more than million times smaller than an atom?

James Messig had suggested “Now imagine that a 1,000 metric ton rest mass ship could be coupled to the black hole via electrically charging the black hole or otherwise setting up a coupling field between the ship and the black hole”

Funny, James Messig contradicts Crane & Westmoreland. Crane & Westmoreland write “Note that if an isolated SBH is initially endowed with an electric charge, then it will quickly, and almost completely, radiate this charge away”.

But wait, there is another problem. Even if you could somehow electrify this black hole contraption the electric field breaks down into a discharge in air at 3kV/mm or about 1kV/mm in vacuum. So you cannot hold an black hole in a container with an electric field.

If you try, one whiff of the electron cloud on the atom and the electron cloud is gone. Another whiff. Another whiff… and before you know it there are millions of naked nuclei without their electron clouds, and an electric force based explosion, because the black hole (BH) of this size could whiz past matter striking down electron clouds in its path without ‘colliding’ with their nuclei.

Crane & Westmoreland write “As to confinement, a BH confines itself. We would need to avoid colliding with it or losing it, but it won’t explode.” They weren’t thinking about massively ionized matter because they had already stated “need to avoid colliding with it”. In their paper they were comparing black hole with antimatter.

Never mind the naked nuclei explosion that is a small matter. The real problem is that the black hole gets lost (because it is 0.6 × 10-18 m small) and it sucks out the air or the Earth, maybe the Sun. Don’t forget black holes love a good meal and will consume anything in their path and get bigger, and bigger … Need a black hole in our neighborhood? No thanks.

2. How do you maneuver the spacecraft?
Remember you are lugging around at least 1,000,000 tons of black hole matter to your 1 ton. Oops, I misspoke, the laws of physics require that it is actually the other way around. 1 ton of spacecraft is lugged around by 1,000,000 tons of black hole matter.

So how does one alter the direction of the Hawking Radiation that this 1,000,000 ton black hole is producing? Archimedes is reported to have said that if you give him a fulcrum long enough he could move the Earth. So what would be the equivalent of a “large enough fulcrum”? Hmmm. I know! Another black hole!

3. How do you collimated gamma rays with a parabolic mirror?
Really? Gamma radiation passes through everything we know of, if the material is not thick enough. Maybe Chown was reporting science fiction? Remember this was 2009. What do you think?

In all fairness I think the gamma ray problem is a more realistic problem than the black hole control & maneuvering problem.

No wonder, Prof. Adam Franks stated in his July 24, 2012 New York Times Op-Ed, Alone in the Void, “Short of a scientific miracle of the kind that has never occurred, our future history for millenniums will be played out on Earth”.

Done. Black hole interstellar drive debunked.

The next blog post in this debunking series.


Benjamin T Solomon is the author & principal investigator of the 12-year study into the theoretical & technological feasibility of gravitation modification, titled An Introduction to Gravity Modification, to achieve interstellar travel in our lifetimes. For more information visit iSETI LLC, Interstellar Space Exploration Technology Initiative.

Solomon is inviting all serious participants to his LinkedIn Group Interstellar Travel & Gravity Modification.


Comments — comments are now closed.

  1. Tom Kerwick says:

    Not a thorough debunk by any stretch of the imagination. I would dispute that a BH may not hold its charge, though a requirement for regular accretion to sustain radiation rates would relegate this to an interplanetary travel fuel concept. Can discuss during the week if interested.

  2. Tom Kerwick. Totally debunked.

    One of my astrophysicist friends who does extensive research into the theoretical physics of cosmology said it was a “great” article.

    Totaly debunked.

  3. I just had a hilarious thought:

    Spaceship owner tells spaceship mechanic, “I lost my black hole. Can you help me find it?”

    Spaceship mechanic asks, “Where? You didn’t lose it around here, did you?”

    Spaceship owner replies, “I’m not sure, the black hole warning light came on a minutes ago, and I thought I’d come straight over to ask you help me find it.”


  4. Tom Kerwick says:

    Perhaps your astrophysicist friend was just being nice to you ;-) What I can say is that carrying the full payload for the journey — regardless of the enormous mass involved — would not work as the rate of HR would not be linear… you would get far less HR at the start of the journey, and it could come to a rather explosive end in the latter stages. Hence one would need to keep feeding the BH to keep it in the sweet spot.

    As for your comments that no-one would want a BH in their neighborhood, I refer you to our good friends at CERN who attempt to create MBH on Earth…

    The main point is whether or not the BH can sustain its charge — so it can be contained. If one debunks that a BH can hold its charge (I don’t believe your casual remarks in above comments are sufficient re electric field breaks down into a discharge) then one debunks BH as a usable form of fuel — regardless of all the other complications involved.

  5. Tom, my astrophysicist friend has decades of experience in theoretical work. Very sharp and not someone to be “nice” when it is incorrect. Maybe your friends are like that, definitely not mine. My friends and I are progressing away from hypothetical conjecture to real engineering feasible solutions.

    If he says it is a “great” article, then it is.

    You contradict Crane & Westmore. They explicitly say “Note that if an isolated SBH is initially endowed with an electric charge, then it will quickly, and almost completely, radiate this charge away”. Note the word ‘quickly’.

    Yes, black hole interstellar drives are totally, totally, debunked.

    CERN’s black hole? Just because some scientists want to do apparently foolish things that does not mean we need to cheer them on.

    And think about the logic of trying to hold at the very least 1,000,000 ton black hole? With what a 1,000,000,000 ton contraption? Really? Or are you suggesting that something on the order of 1 ton will suffice. Think conservation of momentum.

    Assuming you could build a real contraption (not a hypothetical model) think about the energy required. That is like saying we can do interstellar travel with conventional rockets but don’t tell anyone that it will eventually cost $240 trillion or 3.4x World GDP.

    As an academic exercise, I quote Crane & Westmore “we are confident it will pose many interesting problems for classical and quantum relativity”, but as an “engineering feasible” solution the term to use is “on your bike”.

  6. Matthew Ervin says:

    If you are going to “debunk” someone, could you at least give them the courtesy of getting their name right? It’s ‘Westmoreland’.

    And your initial quote from Chown regarding a parabolic mirror is actually an idea put forward by Crane and Westmoreland, except they suggest a parabolic reflector made out of an electron gas.

    I don’t take this work as anything but what it is, speculative. But speculation tends to spur progress.…

  7. Thanks,Mathew Ervin for pointing out the misspelling of Westmoreland. I have fixed it.

    If you read my blog carefully you would notice that I was not debuking Crane & Westmoreland’s academic exercise. I was debunking the possibility that it was somehow engineering feasible. And that is a big difference.

  8. Tom Kerwick says:

    Benjamin — back to your citation that BH quickly radiate their charge, you should note that the Frolov & Novikov paper referred to dates back to 1998, and more recent papers on BH theory — most notably the CERN LHC safety report of 2008 — which was endorsed by the American Physical Society — suggests that BH are likely to hold their charge (though they do some risk assessment on uncharged BH also)…

    I would also suggest you are debunking just a preliminary study and doing so with dubious motivation (to push your book). Such studies should not be kicked to touch in their infancy, regardless of being only on the edge of possibility — after all, all designs of interstellar travel are at best only on the edge of possibility. Best of luck with yours.

  9. Tom Kerwick, if you read my blog carefully you would notice that I was not debuking Crane & Westmoreland’s academic exercise. I was debunking the possibility that it was somehow engineering feasible. And that is a big difference.

  10. And you place intentions in other people’s work that are not there.

    If I was pushing my book I would not have announced Dr. Takaaki Musha and Prof. Mario J. Pinheiro book “Physics of the Zero Point Field and its Applications to Advanced Technology”.

  11. And I might add, even if the published hypothetical conjecture (that is what it is) turns out to be experimentaly verifiable, how would you maneuver a 1,000,000 ton object with a 1 ton craft?

    This defies the laws of physics unless the 1 ton craft is somehow moving a 1,000,000 times faster than the black hole.

    Therefore, debunked.

  12. Tom Kerwick says:

    Benjamin — I have suggested that a TRUE design would be much less than 1,000,000 tons. Note my point regarding maintaining a fairly constant rate of HR for such a craft — its mass would require to be initially smaller and topped up from time to time to remain approx same mass to keep it in the ‘sweet spot’. Also note that it is the BH and not the 1 ton payload that would be the source of energy for the acceleration, so the relative mass is irrelevant.

  13. GaryChurch says:

    Stop feeding the troll Tom

  14. Tom Kerwick says:

    Gary — after writing a couple of papers on BH theory earlier this year ( ) and being on the particle physics and engineering boards here, I feel it is more apt to weigh in my opinion than not. Though don’t be concerned — I do not intend to engage in cyclical debate.