Post a Comment On: Backreaction

This post refers to three articles I read today about Micro Black Holes at the LHC. The articles are in German I am afraid, but I'll briefly try to summarize them.

The first article is rather short and uninspired, and appeared in an online magazine called astronews.com

Schwarze Löcher im Labor? (Black Holes in The Laboratory?)

The second article, which is actually very nicely written, contains a lot of information and also cool pictures, and appeared at heise.de

Experimente mit Schwarzen Löchern (Experiments with Black Holes)

As Andi informed me, both apparently go back to a publication at the University of Frankfurt by Marcus Bleicher und Horst Stöcker:

Schwarze Löcher im Labor? Auf der Suche nach einer experimentellen Bestaetigung der String Theorie (Black holes in the Laboratory? The search for an experimental verification of string theory)

If you look at the above pdf-file, last page, bottom right in the box 'about the authors', you'll find the sentence '[...] work closely together with Dr. Sabine Hossenfelder and Dr. Stefan Hofmann (both at Perimeter Institute, Waterloo, Canada) [...]'.

I am very relieved this piece of information did not make it into the both articles, because a considerable part of the content is complete nonsense. What we reliably know about micro black holes you find in my earlier post, or - for more information - look up this brief summary paper.

Firstly, I should point out that the possible production of mini black holes relies on a scenario with large compactified extra dimensions, without these, nothing will happen. So far, there is absolutely no evidence for the existence of these extra dimensions. (See also Lisa Randall's book Warped Passages). Nevertheless, the possibility that quantum gravitational effects could potentially be observable at the LHC next year is just fascinating, and has been explored during the last years. I too have worked on predictions for the LHC.

Especially the production of micro black holes is a topic that I've found very exciting, because it is one of the most general expectations that we have. When gravity gets too strong, one makes black holes. This is fairly independent of the exact details. The precise properties of the black hole's decay however will be model dependent, especially in the late (Planckian) stages. Some argue that there might not even be a final decay, but that a 'black hole relic' remains: a thermodynamically stable black hole of about Planck mass that does not evaporate. For the case of LHC, these relics would have mass of the order TeV (about 1000 times a proton mass), or a diameter of the order 1/1000 fm. (In case you don't know what a fm is, this is really tiny.) Nobody knows whether black hole relics exists. Most don't think so, me included.

The three articles above feature an 'idea' by Horst to use black hole relics to convert mass into energy. You find this mentioned in hep-ph/0607165, section 6. The idea is roughly that one pushes matter into the relics. Thereby their mass increases, which means they are able again to evaporate. They evaporate back down to their original mass, thereby releasing the matter that was pushed into them in form of energy. Thus, one has converted mass into energy.

The astronew article closes with

"Should the production of stable relics at CERN in the next years be successful, then the energy consumption of the whole earth could be provided with only ten tons of arbitrary material in these converters. The search for the micro black holes therefore is a profitable matter."

Well, unfortunately this idea is very far from being realistic. Since I know both Horst and Marcus, I really don't like to do this, but I just feel that I have to point out this is scientifically complete nonsense: The black hole relics are very small, and have an extremely tiny cross-section. This does not only mean it's impossible to store them (when they are uncharged), this also means you can't feed them. This exactly being the argument why the black holes don't grow and eat up the earth.

Even if you'd run the whole LHC for each atom of the matter that you want to 'push' into the relics of size 10-18 m, you'd have very little chances of success. To put it boldly, if you want to convert your empty coke cans into energy, you'll have to push them into the relic of the size 1/1000 of a proton's diameter.

But let's leave aside the coke cans. What do you think how profitable it would be to run the LHC to convert even a single proton into gamma rays? And even if, then what? Use it to heat water by cooling the detector? And notice that you can't put these relics together to get a larger one (even if you could store them) because they would merge, evaporate and leave you with only one relic.

Look, I really am a friend of speculative ideas, but for scientists it is irresponsible to distribute gross misinformation like this. I've talked again and again to Horst, and I like to think that he is aware of this issue.

However, I can also tell you in how far this is profitable: getting research funding for theoretical physics is tough, in the USA as well as in Germany. Media attention helps. And recently, by a new decision, each patent hold increases grants...

One might want to blame the notoriously problematic financial support for this. One might also want to blame the journalists for not being skeptical enough, or - more importantly - the referees and editors who accepted papers that contained this nonsense.

But eventually the responsibility goes back to the scientist. I think it it ethically unacceptable to publicly spread this scientifically unjustified idea. I neither think this is cool, nor fun, and I want to strongly distance myself from this 'patent'.

If you avoid the part with the energy conversion, I can recommend the article at heise.de.