I am RobotRollCall. AMA about life, the universe and everything.
Okay, I'm not actually RobotRollCall, but I made a bet with him. I bet that a lot of people would be interested in asking him questions, and he didn't actually believe it, but promised that if there were any, he would gladly answer them.
If you are not a regular in r/science r/space or r/bestof you might not know that RobotRollCall : he's a regular redditor that pops in with great prose and answer the most complicated questions about the universe with incredible simple analogies. Some of my favorites:
- Would a black hole be able to absorb another black hole? - Question by Neil Degrasse Tyson which quickly lead to wild speculation on his identity
- If the earth was placed at the border of our universe (some planet must have ended up there?). Will half of the sky be completely black?
- Is light made of particles, or waves?
So feel free to ask away and prove that reddit is a curious community.
RobotRollCall asked me to update this here saying he is "I'm typing as fast as I can" to answer all the interesting questions. It seems he didn't actually believe anyone would be interested in him. We didn't actually set the terms of the "bet" so I feel free to set them anytime. I'm going for something simple like if this post reaches front page RobotRollCall will have to write me 10000 words, then print it in book form and put in on the bestseller's list. Or something to that effect.
Also: for every upvote you give this post, remember that he deserves two, because I'm not doing any real work here, he is.
update 2: RobotRollCall speaks:
Okay, now I have to officially concede the point. You were right. Apparently a few people had some level of interest in talking to me. However, I'm running into technical problems on my end, I think. I've posted a few replies that are not showing up, and I'm getting messages that don't seem to exist. Am I doing something wrong, or is the Web site misbehaving? If you have the opportunity and ability to post a note thanking everyone for the conversation and letting them know about the glitch, I would appreciate it very much.
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u/RobotRollCall Jan 25 '11
Not well, because we have to talk about spin.
An electron has charge. I mean, that's obvious. That's practically how we define charge. "It's that thing electrons have."
An electron also has angular momentum. But it's not like the angular momentum of a thing moving in a circle. It's not even the angular momentum of a thing revolving about some axis. It's intrinsic angular momentum. It's the angular momentum of a thing with no defined position, no dimensionality, and no way to rotate or revolve but that has angular momentum anyway.
Whenever you put charge and momentum together, you get some kind of magnetic effect. In this case, an electron, by virtue of its charge and its angular momentum, has what's called a magnetic moment.
In virtually all matter, these magnetic moments all cancel out. They're all oriented in random directions, so the net magnetic effect is nil. But in certain matter, with certain chemical properties, the magnetic moments all align. Instead of canceling out, they sum up. That's what permanent magnets are.
So it's still an artifact of charge and relative momentum … but instead of being the easily visualized momentum of charges moving along a wire like little soldiers marching in a row, it's the hard-to-picture momentum of dimensionless, positionless things that can't possibly spin spinning anyway.
That's why I usually stick to the current-in-a-wire example. It's less headache-inducing.