Tuesday, May 02, 2006

Honest Questions

I volunteered!

I volunteered to bring a question to our gravity lunch next Friday. Now I am wondering what to ask the brainy guys. How about: why are there hundreds of postdocs discussing the existence, properties and numerical investigation of black holes, black branes, black strings, black rings, or short: black things? (Though I have been told the technical term is black THINGIES.) Black thingies may be boosted, rotating, magnetic, deformed, bumpy or bumpier, potentially unstable, but mostly extreme, and certainly in extra dimensions.

Other questions that currently puzzle me is what a particle is, or why women plug out their eyebrows and then paint them back on. But I figure none of these interesting questions is really appropriate.

Besides this I am preparing a seminar I have to give next week here at UCSB. Since the unwritten law is that questions I can answer won't be asked, I currently wonder what a quantum algebra is (don't ask) -- not that it has anything to do with the seminar.

However, thinking about questions, I wasted time classifying the type of questions I have encountered in multiple seminars and parallel sessions:

1. The commenting question

Starts most often with the words: "It is more a comment than a question..." and serves to prove that the person asking knows something about something, most likely his/her own work. This is the most comfortable question to encounter, and can actually be very interesting, even if it has nothing to do with your talk.

2. The completely irrelevant question

Is the most common question, and one that you might want to practice when you like to draw attention to yourself. To give an example, I have been asked once how many pions a black hole emits (couldn't care less). Here are some very universally applicable members of this family

  • What about the Cosmological Constant?
    (Yeah, what about it?)
  • Can you couple a massive scalar field to your model?
    (Sure, but why would I?)
  • Does that work in an arbitrary number of extra dimensions?
    (Some particular number? 10 or 11 by any chance?)
  • Can you say something about chiral symmetry?
    (Plenty, but that's got nothing to do with my talk)
  • Is there any relation to the recent work by XYZ?
    (No idea, never heard of them.)

3. The never-ending question

Starts most often as an interruption -- say on slide 2 -- and has the answer: I will come to that later -- say on slide 34. Not satisfied with this answer, the person asking will insist on further and further details, thereby completely destroying the structure of your talk which you have been thinking about for the last weeks. If the chair person fails to pull the pump-gun, my advise is to simply ignore the questions.

Another kind of never-ending question is asked in the end of your talk, and requires you to remember every detail of every calculation, parameters of the numerical investigation, factors 4 Pi, references to people whose names you can't pronounce, starting dates of experiments you can't remember, rotation directions in complex planes, and will make you ask yourself why the fu*k you did this work at all. Maybe we can discuss that in the coffee break.

4. The stupid question

Requires very much politeness, since we don't want to embarrass anybody, do we? Stupid questions are frequently asked by those who missed the beginning of your talk. Like: what is d, when you have been talking about the number of extra dimensions for 1 hour.

5. The dangerous question

Is most often asked by senior scientists and frequently comes with an attempt to appear harmless, like "It is probably a stupid question, but..." or "I must have missed something, but..." In case you encounter such a question, consider faking a heart attack on stage.

6. The honest question

And then there are the occasional honest questions from people who genuinely try to understand your work. Honest questions have made me realize many times what direction to look for further insights, and have brought up viewpoints I might have completely missed on my own.

See also: my new poem Honest Questions.


  1. Does the Equivalence Principle (EP) have a parity violation? Do local left and right hands vacuum free fall identically? Newton and Einstein say "yes; the EP is parity-even." Cartan, Weitzenböck, and heterotic string theory say "no; the EP can be parity-odd." Somebody should look.

    All composition EP tests have exactly nulled,


    Hyper-bound, hyper-spinning, hyper-magnetized, superconducting neutronium (binary pulsars) orbit to General Relativity spec within experimental error, including orbital decay from gravitational radiation. What else is there to test?


    There is only *one* EP violation between 10^(-10) and 10^(-13) difference/average consistent with gravitation theory and 420+ years of observation - a geometric parity violation. Spacetime then has a demonstrated chiral pseudoscalar vacuum background.


    Does a single crystal solid sphere of parity space group P3(1)21 quartz (right-handed screw axes) vacuum free fall identically to a macroscopically and compositionally identical single crystal solid sphere of parity space group P3(2)21 quartz (left-handed screw axes)?


    Somebody should perform the parity Eötvös experiment and find out.

  2. There is the opposite problem as well: You sit in the audience and want to ask a question. Or you are the chair and nobody asks a question therefore politeness dictates you have to ask a question. What do you ask?

    In my time at DESY, I learned that at least at least if the abstract of the talk contained "next to leading order (NLO)" or even "next to next to leading order (NNLO)" there is always a sure bet: You just ask "Which scheme did you use?". Or in case the speaker had already stated he/she uses scheme XYZ, you ask "why did you use XYZ and not ABC?". And I promise, if you don't ask that question, somebody else surely will.

  3. Thats a very good question - reminds me of an obscure reference to...

    Opps, did I miss the point of your blog entry? Were you actually asking for questions? ;o)


  4. Dear Bee,

    that's an intersting idea, this question thing for lunch. How is it supposed to work? Someone - you this Friday - has to come up with a maybe naive question, but one that is deep and difficult to answer? Questions that usually are not discussed? What, for example, have been typical questions in the past?

    Your general classification of questions really hits the mark! Questions of type 1 and type 6, I have usually taken them quite seriously, thinking about them long after the talk. When compiling my thesis, I was thinking several times, about this or that issue, there was once this good question, maybe I should comment about this point in more detail... I guess it has in general improved the text, but also inflated it ;-)

    Best, Stefan.

  5. What, for example, have been typical questions in the past?

    You mean besides those about black THINGIES?

    Well, the problem is there are too little questions. That's why Don was asking for volunteers. I think the question should better not be too deep and difficult to answer, I don't want the lunch meeting to last until dinner ;-)

  6. How about these:

    Did Hawking really need all that math stuff to show that information is never lost in a black thingie? When he could have simply said that as a particle approaches a singularity the uncertainty principle allows the particle to scatter in some random direction away from the singularity, re-emerging at some point on the event horizon in the future?

    Or what about this:

    Does Godel's Incompleteness theorem gaurantee that it is impossible to find a grand unified theory of all thingies black or otherwise coloured?

    and this:

    How is it that we live in a universe that allows for more degrees of intellectual freedom than nessecary? I mean why isn't the universe constrained so that we could simply deduce the laws of the universe by you know going 'so we have numbers 1,2,3... thus everything else follows by deduction'?

    Oh and your poem reads very well while listening to 'I can't wait' by the White Stripes, who I think I've been listening to too much lately.

    Good Luck!


  7. I mean why isn't the universe constrained so that we could simply deduce the laws of the universe by you know going 'so we have numbers 1,2,3... thus everything else follows by deduction'?

    maybe it is, we just haven't figured out how to do that. would be rather boring though.

  8. Sounds scary, but you forgot question repeater. you know, the questions that get asked and asked and asked, and the asker usualy only changes the sentance structure and isnt actualy listening to your answers?

  9. you forgot question repeater

    Ah, thanks for pointing that out :-) I would say, it's a subclass of the never-ending question. An eternal bounce.

  10. Random question:

    Wick rotation

    It works, and is needed in many calculations -- does it mean anything physically? Does it relate Riemmannian and Lorentzian spacetime, or is it just a calculational trick?

  11. And the meaning of life is 42, but we don't yet know the question.

    I too can recite the geek catechism.

    Now where did I put that towel...


  12. Garrett said: Wick rotation

    It works, and is needed in many calculations -- does it mean anything physically? Does it relate Riemmannian and Lorentzian spacetime, or is it just a calculational trick?

    It means something. The dolphins told me.

  13. Wick Rotations? I don't understand what do spinning Druids have to do with anything?

  14. Not Wicca rotations, Wick rotations!

    With my luck, the earth will be destroyed before this question is clarified.

    There was actually a pod of spinner dolphins out this morning where I was surfing. I asked them about Wick rotations, but they said I should go consult the spinor dolphins.

  15. So, what was your question, then?
    And was it answered in a satisfactory way?


  16. The question was "Why do we live in 3+1 dimensions?". I would have been very surprised if someone had been able to answer it. Will write more about it soon, have to get my seminar slides done now.

  17. Oh, that...
    Well, if you can stomach anthropic arguments:

  18. Garrett, I was about to write a post about our gravity lunch last Friday. Thanks for the link, the funny thing is, thats were the discussion ended at. As Don put it: Well, if you wanted to go anthropic, we could have gone there directly! ;-)


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