answersseptember

09-10-01 I need a new mouse, mine keeps double clicking on it's own, it makes resizing and moving stuff a huge hassle. Anyway, the sky is a pretty nice thing. I think you should go all go for a 20 minute walk today, during the day though.
      Okay, the first September questions comes to us courtesy of Tim. Tim asks:
"How does the act of observing change the observed?"
     Nice. Oh, you should get a Feb. 2001 issue of Scientific American (I know that I constantly tell people to get sci. am. issues, but I'm not getting paid for it or anything) since the forthcoming explanation is heavily based on an article by Tegmark and Wheeler found in that issue. .
    Ok, say you've got a card with a finely polished edge. Say you put it up on its edge, according to quantum mechanics (shrodinger's wave function, to be precise), it will fall both to the right and left; a superposition. Now we can't have a card that's both face and and face down, or a cat that's both dead and alive, so what's going on here?
     In the 1920s, Bohr and Heisenberg discuss this whole superposition mess, and what results from these discussions is called the Copenhagen Interpretation. They said that as long as the card is unobserved, it's wave function's evolution is unitary (smooth and continuous), and it does fall both to the left and right; but, as soon as you observe it, the wave function collapses, and you see it in one distinct state (on the left or right). According to the copenhagen interpretation, nature randomly selects which state you will observe (face up/down), with the probabilities determined by the wave function. Now, the Copenhagen interpretation was fine to work with and use in calculations, and it provided accurate results that matched experimental outcomes, fine, but it didn't tell us anything about when or how the wave collapses.
     We move forward to Princeton University, in the 1950s, to see what Hugh Everett III was up to. Everett comes up with something called the Relative-State Formulation. He says that if the present state of the entire universe is described by a wave function, then what if the time-evolution of the entire universe is unitary?   Basically, he said that the wave function never collapses, instead, not only does the card exist in a superposition, but so does the observer, so she exists in two different "worlds" where she sees the card fall to the left in one and to the right in the other. So you end up with all these parallel perception of reality that are all equally real.
     Then, in the 1970s, H. Dieter Zeh of the University of Heidelberg comes up with decoherence. It was called decoherence because an ideal state of superposition was said to be coherent. Zeh and his buddy Zurek worked decoherence out in great detail. Lets say you have some mechanism to put a card up on its edge inside a box or something, so that when it falls, nobody can see if it fell face up or face down. According to what's been said in the preceding paragraphs, it's actually lying both face up and face down. As far as you know, it's both face up and face down, but lets say I'm hanging out with you, and decide to peek in the box. Now, I saw it as being either face up or face down and collapsed the wave function, so I destroyed the superposition, and now when you look at it, you'll see what I saw. Ok, what Zeh and Zurek suggested is that you don't need me to look at it, I can be replaced by air molecules, photons, etc. and you don't even need a wave-function collapse.
    Ok, lets say we get rid of the enviornment then, and leave only the observer and the object. Say you do your card thing in a dark vacuum chamber at absolute zero. You've got no pesky air molecules or photons or anything else to mess with your card and destroy the superposition, it's just you and the card. What happens? Well, you've still got to observe and perceive, so little neurons in your brain fire, and then decoherence occurs.
    Ok tim, start paying attention here. Here's the quick run down it all. "Our brains are inextricably interwoven with the enviornment, and decoherence of our firing neurons is unavoidable and essentialy instantaneous" - Wheeler and Tegmark. So as long as you're there to observe the object, you're gonna "change" it.
    Speaking of cards and stuff, that Davind Blaine is one cool cat.

We also have this from Mike:
"Some crazy stuff's been happening lately, what do you think?
'an eye for an eye leaves everyone blind' -Gandhi"
      ...What do I think? I think that Jackie is great and that soda is good. About the "crazy stuff", I don't know. I feel very detached from it all; like you'd feel when reading about an event in a history book. I think about 7,000 people die in America everyday...but even from that perspective, watching 5,000 people die being replayed over and over is still strange and intense. I don't care much about the dead people, death isn't a big deal for the dead, I'm more concerned about those they left behind. I haven't thought about my feelings on this issue that much, so excuse these disjointed little statements.    I was glad to see everyone helping everyone else, maybe now all those conrad freaks will stop all that "inherent darkness blah blah" crap, since most of the helping did seem to be instinctive.
     Also, I think the taliban are evil and need to be replaced, and I would've though this even if the events of the 11th hadn't occured. The US should really support the United Front, and I hope when victorious, they will carry out the late Mr. Massoud's plans for a democratic afghanistan. I've been seeing a lot of knee-jerk-reactions in these past few weeks; whether it's the "kill em all" mentality, the pseudo-anti-american-midnless-naom-chomskites running around with their prewritten babble about foreign policy "mistakes" from many decades ago, or people urging us to "choose the peaceful solution" without ever providing one. It seems as though most people view the events and think "how can I fit them into my pre-existant beliefs and opinions" rather than "how does this affect my beliefs and opinions".
       I also see the word "WAR" everywhere I look, as if it's some new phenomenon. The majority of people throughout history have experienced war, it isn't anything new.
       All in all, I think that this is a good opportunity to get rid of the taliban and bin laden (who's basically a megalomaniac with too much time and money), but we must first have a very clear objective and methodical plan to follow.
      I don't like talking about this.
     Oh, a gandhi quote, eh? Gandhi was an interesting fellow, his family (wife and kids) almost died once because they were poisoned and he refused to let them take the antedote. Gandhi brings the Baghavad Gita to mind, which is strange, since he was a pacifist and the whole Gita was pretty much Krishna telling Arujna to fight. I liked it's message though, about how it's not killing people, it's letting go of your selfish concerns with the outcome of your actions. Interesting book, check it out, Mike. On an irrelevant side-note to an irrelevant side-note, Dharma, in sanskrit, means "truth, nature and duty" (note that is it "truth, nature and duty" not {"truth", "nature", and "duty}). Basically, it means that peronal truth and one's duty depend on one's nature. I think they classified people into 4 types, those who care only about themselves and the present, those who care about their family and friends and their entire lifetime, those who care for all humanity and all history/time, and those who care only about the infinite/spiritual. So whereas Arjuna's nature was of the 3rd type, it was his duty to fight, eventhough he said he "would rather die than kill another human being". This whole darhma thing is kind of like my own concept of social irresponsibility, where we are only responsible for our own expectations. Anyway, enough of this. Have a good day.

ok, Andrew Schran is back with another question:
"How does the amount of mass in the universe affect whether it will (a) keep expanding forever, (b) collapse and then explode again (Big Crunch and then another Big Bang), or (c) go static (expand to a certain size and then stay that big forever)? This assumes that the only outward force pushing galaxies away from each other is that remnant from the Big Bang, and the only inward force making the universe come back together is gravity."
Ok, lets take a look at Newton's law of gravitation: every particle of matter attracts every other particle with a force directly proportional to the product of their masses and inversely proportional to the square of their distance...or something like that. We can ignore that second part and just look at the thing about the force being directly proportional to the product of their masses (more mass=greater gravitational effect). So, the more mass in the universe, the harder it pulls on itself (every particle pulls on every other particle). A and B are pretty straight-forward, if there's more mass then needed to create a gravitational force that will overcome the initial force of the big-bang, then B will happen, if there's less, than A will...I don't know the numbers off the top of my head so I can't tell you how much mass would be needed (I could look in my stack of nerd-magazines, but they're too far away). As for C, it gets tricky; a static universe would need a cosmological constant or something of that nature. For now, scientists think that we don't have enough mass for B, so our universe will probably expand forever...and since stars are dying much quicker than they are "being born", it might end up very empty.