Madame Wu

August 14, 2002 2:01 PM

Madame Wu Through the Looking-Glass: If you look into a mirror, you might wonder if that mirror-world is a possible world. This mirror-symmetry possibility is known in physics as parity conservation. Well, 1956 was the year that Parity fell. That's the year that Madame Wu created and performed an experiment that revealed once and for all that the Looking-Glass world is not the same as ours. This is an epochal discovery. Nature distinguishes between left and right. Here's some basics of Madame Wu's revolution. Why isn't she better-known outside of Physics? And why wasn't she awarded the Nobel Prize?
posted by vacapinta (27 comments total)

So what does that say about the True Mirror?

Seriously though, great stuff, vacapinta.
posted by liam at 2:23 PM on August 14, 2002

Three points for posting the most brain-hurty link of the day. Fascinating stuff.

This reminds me of a conundrum I once saw posted on rec.puzzle: You have been captured by aliens and placed in half of a round, featureless chamber. This half-circle chamber is then replicated and mirror-inverted to create a round chamber, complete with a duplicate you on the other side. Everything has been duplicated perfectly -- sub-atomic particle for sub-atomic particle -- and the other you is in the exact same relative position that you occupy. although your "right" is his "left" and vice versa. You start to speak to the other you, but, of course, he speaks at exactly the same time, saying exactly the same words. You approach, he approaches; you back off, he backs off. The question, then: is there anything you can do to "unlock" your actions from those of your doppleganger?
posted by Shadowkeeper at 2:36 PM on August 14, 2002

This is off-topic, but I can't find any information on the web. What happens if you line up a mirror perfectly with another mirror?
posted by agregoli at 2:47 PM on August 14, 2002

Shadowkeeper: I'd start dancing. Ain't no one keep up with me when I get my groove on.
posted by holloway at 3:08 PM on August 14, 2002

Shadowkeeper, I think I have an interesting solution. I'd cut off my left hand and then start to masturbate. By cutting off my left hand, my doppleganger would be forced to cut off his right. And then he would be forced to masturbate with his left hand, which for me and my doppleganger would be a very clunky process vs. my sleek right handed masturbation. It would certainly unlock our actions as we would not finish at the same time. If you have a better solution I'd certainly be game so I wouldn't have to chop off my hand or masturbate in front of my doppleganger.

Great link Vacapinta!!
posted by Mushkelley at 3:22 PM on August 14, 2002

agregoli - just don't stick your hand in there...
posted by kokogiak at 3:22 PM on August 14, 2002

Parity is also the reason lemons and oranges smell different:

Orange and lemon peel both contain a molecule called limonene. However, the limonene molecule in orange peel has a different structure than the limonene in lemon peel. The different structures have different smells. The types of limonene in oranges and lemons are mirror molecules. The molecule in the orange is "left-handed," and the one in the lemon is the "right-handed" version.

Since life as we know it is left-handed, that is, our amino acids are all left-handed molecules rather than their mirror-image right-handed ones, and some scientists believe that life on earth started split evenly between left- and right-handed amino acids, but was nudged to the left by the influx of organic-laden meteorites, does this mean that oranges are from outer space and lemons are terrestrial?

(The above is cribbed from an old blog entry of mine, on a slightly different but related topic. Brilliant post, vacapinta.)
posted by gleuschk at 3:26 PM on August 14, 2002

Is anyone really stumped by the left-right, up-down mirror thing? I've asked 5-year-olds that question and they've understood that the mirror is reflecting, not reversing, an image.

If that link with the pictures of the wire coils accurately describes Wu's experiment, it's no wonder she didn't get much recognition. First-year physics and EE students would know how to apply the right-hand rule to determine the polarization of the apparatus. The author of that page shows the action of the electromagnetic force and ascribes the results to the weak force.

What happens if you line up a mirror perfectly with another mirror?

If your mirrors are finite in size, you will see the image of each mirror in the other, with the reflected image ad infinitum. Pushing the mirrors closer together to eliminate the effects of perspective will only have an effect as the distance between them goes to zero. At that point, no light can enter to cause reflection and nothing will appear in either mirror. Of course, that supposes perfectly reflecting mirrors with no edge effects. It would also be the optical equivalent of a tree falling in the fores
posted by joaquim at 4:13 PM on August 14, 2002

...it's no wonder she didn't get much recognition

Oh, she's received much recognition. I apologize if that was confusing. Physicists know who she is but for some reason she is one of those figures that is almost unknown to outsiders despite the stunning implications of her work - thus the motivation for my post.

Of course, whether she deserved to share the Nobel with Lee and Yang is, I agree, controversial. I think so.
posted by vacapinta at 4:59 PM on August 14, 2002

My head hurts and I'm scared.

Great link. Haven't a clue what they're talking about, but have learnt just enough to sound impressive when at the bar. UNless M.Wu happens to be drinking next to me.
posted by ciderwoman at 5:00 PM on August 14, 2002

If your mirrors are finite in size, you will see the image of each mirror in the other, with the reflected image ad infinitum. Pushing the mirrors closer together to eliminate the effects of perspective will only have an effect as the distance between them goes to zero. At that point, no light can enter to cause reflection and nothing will appear in either mirror. Of course, that supposes perfectly reflecting mirrors with no edge effects.

but if they're perfectly aligned, there is no perspective? I know I'm not that smart scientifically, but I still don't understand. I also don't understand "finite in size."
posted by agregoli at 5:27 PM on August 14, 2002

Fascinating link, I love this stuff.

While I'm loathe to ascribe her lack of Nobel to sexism without a lot more information, I felt this quote about women in US science was priceless:

" ... it is shameful that there are so few women in science... In China there are many, many women in physics. There is a misconception in America that women scientists are all dowdy spinsters. This is the fault of men. In Chinese society, a woman is valued for what she is, and men encourage her to accomplishments --- yet she retains eternally feminine."

It's sad that what was true in the 1950s is, for the most part, still true today.
posted by frykitty at 5:41 PM on August 14, 2002

to ascribe her lack of Nobel to sexism without a lot more information,

Well, what info are you going on right now, frykitty?
posted by holloway at 5:58 PM on August 14, 2002

Okay, how about this one? Imagine a sphere, perfectly round, with a mirrored interior surface. You are floating in the middle of the sphere. What do you see in the mirrored surface? For how I get my brain around the concept, you would somehow see everything everywhere... every direction you look you would see a reflection of the surface directly opposite. I don't know. It would be kewl to try it though.
posted by Jimbob at 7:52 PM on August 14, 2002

"Madame" Wu mused: " ... it is shameful that there are so few [American] women in science... In China there are many, many women in physics."

Interesting choice of words, for an immigrant to America. That wouldn't have anything to do with the brutal proletarian fasco-communist 'cultural revolution' would it?

I wonder if she can see her high horse in the mirror?

Interesting links, thanks, vacapinta.
posted by hama7 at 8:03 PM on August 14, 2002

I don't know. It would be [...] to try it though.

O god please don't use that word.

Your sphere example is fatally flawed: if there were anything in the interior of the sphere, you would see that as if in a concave mirror. If there were not, then there would be nothing to see.
posted by gleuschk at 8:06 PM on August 14, 2002

is there anything you can do to "unlock" your actions from those of your doppleganger?

wait so like you could both drink (really, really strong) lemonade, and because yours would be super sour and your (tesseractly transposed :) doppleganger's would be super orangey, you'd be all puckery and your mirrored self wouldn't!?

wouldn't have anything to do with the [..:] 'cultural revolution' would it?

or the japanese occupation!!..iirc :)
posted by kliuless at 9:33 PM on August 14, 2002

Well, what info are you going on right now, frykitty?

*bites off snarky comment about not reading links*

It's the last link in the post, holloway.
posted by frykitty at 10:32 PM on August 14, 2002

Interesting choice of words, for an immigrant to America.

Why?
posted by lia at 10:46 PM on August 14, 2002

I read the links. I wondered if you had any definitive insights to the nobel commitee's decision-making process around that era. You know, like evidence. Evidence is what keeps people from jumping to lazy conclusions.
posted by holloway at 10:54 PM on August 14, 2002

Interesting choice of words, for an immigrant to America.

Why?

lia: I tried to explain it above.

There was no choice of profession under the communists. Governmental appointees do not equal freedom to choose one's occupation. And why did she choose to flee China if the opportunities were so bubbly and wonderful. I wonder?
posted by hama7 at 11:06 PM on August 14, 2002

The Nobel committee moves in mysterious ways and it is futile to attempt to guess their intentions. Madame Wu, however, is on the short-list of physicists who probably should have gotten a Nobel.

I think the biggest injustice in the Physics Nobel was when Penzias and Wilson (who accidentally discovered the Cosmic Microwave Background) were given the Nobel over Dicke and Peebles who had predicted its existence and were already looking for it. Many are still scratching their head over this one. If you notice, this is almost a mirror (heh) of what happened with Wu and Lee/Yang (except Wu's experiment was no accident).
posted by vacapinta at 12:18 AM on August 15, 2002

but if they're perfectly aligned, there is no perspective? I know I'm not that smart scientifically, but I still don't understand. I also don't understand "finite in size."

I should have used "angle of incidence" rather than "perspective". If two finite mirrors are perfectly aligned (and I'm assuming this means they are offset in only one axis), what you see in each mirror will be the reflections of things whose images have come in past the edges of the mirrors or are in between the mirrors (plus the mirrors themselves). Infinite mirrors would block the images of everything behind them, so the mirrors would only reflect what's between them. If the mirrors are perfectly reflecting, you would not see the mirrors themselves because you could not see those edges out in infinity that define the mirrors
posted by joaquim at 10:22 AM on August 15, 2002

I understand that - I think. However, that's my point. IF this was possible (and I don't think it is), what would the mirrors reflect? I realize no one would ever be able to see what they did reflect, and that's interesting.
posted by agregoli at 10:32 AM on August 15, 2002

I tried to explain it above.

Well, sort of, but rather snarkily. Don't immigrants have the right to criticize their new home? Or are they supposed to shut up and be grateful and not point out disgraceful things, like the serious dearth of women in science and engineering then (and now)? The truth hurts, suck it up.

There was no choice of profession under the communists.

In a way, there was, or at least there was some attempt at gender equality -- at least women like Wu who had the aptitude for the field could get a good education and find work. Can you say the same thing for many other countries at the same time, including the US? My mother and three friends of hers got graduate degrees in the US during the 50s. Three of them were chemical engineers, the other was getting her MBA, two were in Ivy League schools, and each was frequently the only woman in their classes. The thing is, many women going into the sciences today can say the exact same thing (as frykitty pointed out earlier), and that's not just shameful but tragic.

And why did she choose to flee China if the opportunities were so bubbly and wonderful. I wonder?

FYI, none of the links on this page say Madame Wu "fled China" or why she left, so you're reaching.
posted by lia at 10:54 AM on August 15, 2002

The way my professors describe it, the Nobel committee seems ridiculously political. Watson not only did the double-helix thing, but then helped discover the genetic code. But the Nobel mafia ignored the code stuff because he'd become unpopular by yukking up his DNA-boy celebrity too much and pissed off the scientific community.
posted by gsteff at 11:14 AM on August 15, 2002

> Okay, how about this one? Imagine a sphere, perfectly
> round, with a mirrored interior surface. You are floating
> in the middle of the sphere. What do you see in the
> mirrored surface?

You would see yourself turned inside out, with your extremities protruding inward.
posted by jfuller at 3:05 PM on August 15, 2002