Sunday, October 5, 2008



  1. Che bello!!!! bella la foto (questa non l'avevo mai vista) e bella la musica.

  2. Grazie, ma non mi piace come la foto e' venuta fuori. in realta' non sono riuscito a togliere il bordino chiaro quindi mi sa che la rimuovo... o ne metto un'altra!

  3. A me piace!!! è particolare :)(lo sai che ti copierò spudoratamente il cosino con la musica vero? :P)

  4. adesso riprovo... te ne ho mandate 3 di mail all'indirizzo che hai scritto! Diavolo, per una volta che ho l'ispirazione... (niente di che eh, però...) ;)

  5. Reading this Italian is almost as nice as looking at the photos! I have no idea what the words mean but when I try to pronounce them, it's like eating chocolate.

  6. @ kristin: :-D mmmmhhhh... chocolate... my favorite drug!

  7. AC I know this is off topic from "Interlude" but seeing that you are into physics I wonder what you think about the super Hadron collider? Do you think there is any risk?

  8. @ kristin: No, kristin, there is no risk whatsoever. And I know the system, believe me.
    Even if I am not directly involved into any of the experiment there (my main expertise is into gravitational physics) all the fuss about LHC is mainly due to the cultural distance between common thinking and a science whose advances are far too complicated to be explained in simple terms.
    The fear of a black hole destroying the planet is not dissimilar to that of the end of the world in the year 1000 and 2000. LCH is just a (very) complicated machine aimed to reproduce conditions in matter and energy similar to those we think were present in the first instant of the universe. It's a great experiment, whose discoveries will take decades (if not centuries) to be fully implemented into our society.
    Still, energy/matter conditions targeted in LCH aren't so unlikely in everyday life. Earth is hit several times/day by cosmic rays, whose energy is far greater than that achievable by LCH.
    Micro-black holes, provided they exist, may be part of our life already. Usually a micro black hole evaporates in a very short time (they don't just "suck in matter") with a rather cumbersome mechanism related to quantum mechanics (which hasn't been directly observed yet, though).
    Even if this evaporation didn't take place, such a black hole would suck around 100 proton/year, by swinging through the earth back and forth. From its point of view, solid matter is almost completely empty. 100 protons/year means it would take a time comparable to the age of the universe to "eat" 1 milligram of matter.
    I think you can sleep safe and sound.
    I gladly sacrifice 1 mg of my love handles to the deadly black hole... ;-)

  9. Thanks for your answer, I find that stuff fascinating. Just thinking about extra dimensions and black holes and strings....what a crazy world.

  10. Very interesting stuff, -a-c-. Thank you for sharing knowledge and perspective. I love your ending.

  11. aaahh...that photo is a perfect metaphor for the 'waters of march'.

    i could have used that fantastic primer on the LHC about a month ago...the boys were quite curious!

  12. @ kristin: you're right. this stuff is fascinating (I have devoted most of my life to it!). Extra dimensions are very much related to the ability of "producing" black holes. All this expectation about black holes is due to the fact that the probability to make them is related to the number of extra dimensions in our universe. Should they be "only" 4, we wouldn't have any chance to produce BH at the energies LHC should be running. But...should these dimensions be more than 4 (11 for instance) then we would have a greater likelihood to end up with a micro BH, among other particles.
    The ground for this behavior is to be found in the relative weakness of gravitational force with respect to the other fundamental forces in nature (electromagnetic, weak and strong nuclear force). I hope I am not driving you all crazy.... when I start talking about physics I tend to be logorrheic... sorry!

    @ judith: hehe... I wish one milligram were enough!

    @ qualcosa di bello: thank you so much for your comment. As for your boys, I like to say to my students: "ask, and thou shalt be answered..."

  13. Oh I JUST saw your answer today! You are not boring when you talk about physics, I find it fascinating. I tried reading some "pop" physics books. It stumps me but I love thinking about that stuff. Even a microscopic black hole can swallow a lot, though, if I'm not mistaken.

  14. @ kristin: I'm glad you are interested in these topics. Actually BH aren't "all swallowing and no spitting". They also emits particles and radiation in a very special form, theorized by S. Hawking, thereby slowly evaporating. More details on this can be found here:
    This process is very inefficient for stellar size object and therefore balance is much in favor for sucking matter and energy around, whereas for very tiny BHs the situation is reversed, leading to a very quick evaporation in a burst of energy and elementary particles.
    Unfortunately no one has ever closely observed a BH and it is not even clear whether micro BH can exists, let alone be artificially created in a lab.
    Even if the evaporation process turned out to be wrong, a BH that size wouldn't pose any threat at all, an we may well be living among them already without our direct knowledge, as they would be created by the constant cosmic ray shower.
    The radius of a BH increases very very slowly with respect to the "eaten mass". A BH made up with the earth would have a radius of approx 9mm (3/8 "), and to increase its radius of some more mm, it should take up another earth. For this reason, a BH made up of a bunch of protons alone, is too small to even imagine by human standards.
    Truly, given infinite time and no evaporation process, it may end up eating considerable mass, but our solar system would be gone already in a couple of billions of years.


  15. Thanks for your in-depth physics answers! Intersting how someone can be very artistic and very scientific all at once. I think some of those physics attributes you speak of would be very interesting fodder for a "science-fiction" book, especially delving into the quantum and black hole and string realm where it's all just hypothesis anyway. I'll have to think about that....