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Explaining Left and Right to an Alien...

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Simon Bosher
776102.  Sun Jan 16, 2011 10:32 am Reply with quote

Jenny wrote:
Still depends on a physical reference though.


You do not need a physical reference at all to explain left and right only some Nobel prize winning fundamental laws of physics as I shall shortly explain...

Let us accept that it is impossible choose a common coordinate system in which both of us could agree. Nevertheless it would still be extremely easy for us to explain to the aliens which side is left and which side is right with the help of the 1957 Physics Nobel prize winning work of Chen Ning Yang and Tsung-Dao Lee on parity violation of the weak force which occurs in beta decay radioactivity and other subatomic particle interactions involving the weak force such as the decay of Kaons. Their Nobel lectures are downloadable free of charge from the Nobel prize site.

It is a truly amazing fact that the world of subatomic particles can distinguish between left and right via the weak interaction (and this is basically what physicists mean, in layman's language and with some oversimplification, by parity violation) and so all we would have to do is explain an experiment where parity violation occurs. This work is absolutely solid and there has been some formidable talent who have worked in this area including many Nobel prize winners e.g. people like Richard Feynman, Murray Gell-Mann, Abdus Salam, Sheldon Lee Glashow and Steven Weinberg.

There is also a second amazing fact (which is closely related to parity violation) that all neutrinos are left handed and anti-neutrinos are right handed which would give a second easy way to explain left and right to our new alien buddies.

Finally if they do not know any subatomic physics, we might explain to them Fleming's left hand rule or some other physics rule which distinguishes between left and right.

Left and right handedness also occurs frequently in chemistry and biology as Louis Pasteur found, with some biological molecules being only left handed or only right handed in nature. Physics Nobel prize winner Abdus Salam has even suggested this asymmetry of left and right in biology i.e. the preference of molecules of one handedness over the other (even though both forms are clearly possible and even manufacturable in the laboratory) may possibly be due to the weak force. (Go to http://www.springerlink.com/content/kr86w4l65r601655/ but this content is not free of charge).I find all of this really Quite Interesting especially if Stephen were to explain it to us.

I posted this elsewhere instead of here on the QI site. Apologies for this and my late contribution to the debate.

 
Moosh
776372.  Mon Jan 17, 2011 2:54 am Reply with quote

Right, so what you're saying is that we would have to explain to them some experiment which would distinguish between left and right, and then they would have to perform that experiment to see which is left and which is right?

How is that not referring to a physical reference? If you have to do an experiment it's physical reference.

(Though don't take that as a criticism of your post, 'cos what you said was interesting.)

 
aTao
776552.  Mon Jan 17, 2011 1:39 pm Reply with quote

Quote:
Finally if they do not know any subatomic physics, we might explain to them Fleming's left hand rule or some other physics rule which distinguishes between left and right.


Ahh, but.. Fleming's left Hand rule requires the polarity of the magnetic field be defined. Cant do that without pre-defined left and right and electron movement.

The molecule structure is far more interesting since left and right spirals are distinct and dont change handedness with viewing orientation.

But you still need to determine if you are chatting with aliens or anti-aliens?.

 
Simon Bosher
776687.  Mon Jan 17, 2011 8:33 pm Reply with quote

aTao wrote:
Quote:
Finally if they do not know any subatomic physics, we might explain to them Fleming's left hand rule or some other physics rule which distinguishes between left and right.


Ahh, but.. Fleming's left Hand rule requires the polarity of the magnetic field be defined. Cant do that without pre-defined left and right and electron movement.

The molecule structure is far more interesting since left and right spirals are distinct and dont change handedness with viewing orientation.

But you still need to determine if you are chatting with aliens or anti-aliens?.


We would almost certainly be talking with aliens and anti-aliens almost certainly do not exist. Yes I am fully aware of the PCT Theorem. In principle anti-aliens could exist, but this is most likely to be highly intelligent artificial life made out of antimatter which is rather far fetched to say the least! Let us consider the other possibility that some parts of the universe are composed of matter and others of antimatter. Then why have we not seen the frontier regions where matter is eliminating antimatter? If these regions are too far away to be seen, then they will be too far away to communicate with them: after all nothing can go faster than the speed of light.

I respectfully disagree with your point concerning Fleming's Left Hand Rule! One only needs to define a plane facing us with up being force and magnetic field being perpedicular and sidewise (here which way is up and sidewise is quite unimportant so we do not need to specify which is which). Then the current will come towards us. (Of course we must express this as a motor, with a generator we need a right hand rule i.e. the current points away from us). Remember that a motor converts electrical energy into mechanical energy and a generator mechanical converts energy into electrical energy. There is nothing here that requires us to know whether electrons have left or right hand movement. We only need to know whether something is a motor or generator!

But assuming I am wrong both points, I still see you have not refuted my neutrino antineutrino point. I do not see how you can.


Last edited by Simon Bosher on Mon Jan 17, 2011 9:04 pm; edited 1 time in total

 
Simon Bosher
776699.  Mon Jan 17, 2011 8:58 pm Reply with quote

Moosh wrote:
Right, so what you're saying is that we would have to explain to them some experiment which would distinguish between left and right, and then they would have to perform that experiment to see which is left and which is right?

How is that not referring to a physical reference? If you have to do an experiment it's physical reference.

(Though don't take that as a criticism of your post, 'cos what you said was interesting.)


Thank you Moosh for your interesting point.

I disagree that I am referring to a physical reference. Yes I am appealing to the laws of physics but one can easily talk about the laws of physics and the difference between left and right without a physical reference. A physical reference would, for example, be some predefined coordinate system based on the known and commonly agreed facts about the material world. This would be impossible to establish with the aliens (or if it were not so it would be even easier to explain left and right to our alien buddies!).

We could assume that a commonly agreed direction is impossible. But we could define an electron say pointing in an arbitrary and unknown direction and this could be enough, without the aid of reference system, to define left or right. We just need the laws of physics, and, (this is the vital point), we do not need a physical reference to define the laws of physics.

This is most easily seen with the left-handed neutrino and right handed anti-neutrinos as shown here.

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/neutrino3.html

 
aTao
776718.  Tue Jan 18, 2011 12:14 am Reply with quote

Quote:
I respectfully disagree with your point concerning Fleming's Left Hand Rule!


May I suggest that you investigate Fleming's Left Hand Rule with a magnet that some nefarious creature has re-labled so that North and South are reversed.

 
Simon Bosher
776984.  Tue Jan 18, 2011 12:39 pm Reply with quote

aTao wrote:
Quote:
I respectfully disagree with your point concerning Fleming's Left Hand Rule!


May I suggest that you investigate Fleming's Left Hand Rule with a magnet that some nefarious creature has re-labled so that North and South are reversed.


You make an excellent point about the need to explain to the aliens the difference between north and south poles (I think I have a solution to this one but since I did not mention it originally you were absolutely right to bring it up) and I need also to make a correction to a very silly error of my own in the previous post.

1) Before carrying on, I shall need to make some assumptions about our alien

(i) we are talking to an alien and not an anti-alien i.e. our buddy is made of matter not antimatter. To me this assumption is not controversial, but to you it is.

(ii) knows at least as much about the laws of nature as we do and our new friend is an excellent theoretical physicist. This is very likely but by no means certain.

(iii) and has a rudimentary knowledge of English (but still does not know which is left or right) and totally agree with everyone that my assumption here is extremely far fetched. My only defence is that I am trying to ascertain whether, in principle, we could explain left and right without a physical reference frame.

(iv) and finally our alien is really kind being and there is nothing nefarious about him or her or it. (To be fair to you, you were making the excellent point, one that even a nonnefarious alien would make, what is magnetic north and what is magnetic south but it is just that much harder to explain things to nefarious aliens who always want to stitch us up, they are just like that!)

2) Magnetic monopoles, single charges of magnetic charge i.e. with just a north pole without a south pole (or vice versa), may or may not exist. We know (from Paul Dirac no less) what properties these magnetic monopoles should (must?) have. I am not therefore in the slightest bit worried if these things actually exist or not, they can still be used to explain magnetic north and south, using just theoretical physics. I now refer you to wikipedia

http://en.wikipedia.org/wiki/Magnetic_monopole

From which we obtain magnetic monopole quantization condition

q_e q_m/h = Z

where q_e is the electric charge, q_m is a magnetic charge, h is Planck's constant and Z is any integer. Choose q_e to be the electron charge and Z to be +1 or -1 and calculate q_m. One of these will be a north monopole and the other a south one (I do not know off hand which is which). I hope you will agree that I can explain to an alien which is north and which is south (once I have worked out which is which!). So much for my attempt to avoid subatomic physics in my original post in giving an example outside subatomic physics. I have obviously failed to do that, but my main aim was to qibble with this QI program in question.

3) Next I must make an apology. I incorrectly stated that

"here which way is up and sidewise is quite unimportant so we do not need to specify which is which"

This is obviously complete tosh. We are going to have to do a lot better than I did in that post and we shall do so.

4) Our next task is to define up. This is most easily done by explaining up as the direction going away from the planet and down as going towards a planet. This is the direction of the force or thrust. We can even make it a hypothetical planet if you like.

5) We next need to explain away and towards (this one is very easy) and let the current comes towards us.

6) Now we need to define the direction of the magnetic field going from north to south. Thanks to our magnetic monopoles our alien buddy already knows what is north and south (that is assuming the alien is smarter than me which would almost certainly be the case). Now if we have a motor the field goes left and if it is a generator it goes to the right.

See

http://en.wikipedia.org/wiki/Fleming%27s_left_hand_rule_for_motors

http://en.wikipedia.org/wiki/Fleming%27s_right_hand_rule

Yes it is very hard to do, explain left and right to alien, but I hope that I have shown that it is possible with the laws of physics and without the need to a reference to the physical world. Remember we can formulate the laws of physics without such a reference. This is a subtle but important point.


Last edited by Simon Bosher on Tue Jan 18, 2011 8:11 pm; edited 1 time in total

 
Ainee
777096.  Tue Jan 18, 2011 5:43 pm Reply with quote

gerontius grumpus wrote:
Couldn't left and right be explained in relation to electron spin in atoms or the most common arrangement of asymmetrical molecules and their effect on polarised light?


Lol, not be me it couldn't be.

I shall get my teenage sons to find out how. Young minds are better at this sort of thing.

Honestly, the things that you people talk about on here....

All best wishes, Ainee


Last edited by Ainee on Tue Jan 18, 2011 5:45 pm; edited 1 time in total

 
Ainee
777097.  Tue Jan 18, 2011 5:44 pm Reply with quote

I can't even get the quoting arrangement sorted yet.

Pffff

Aha! Fixed it!

Ainee

 
Simon Bosher
777149.  Tue Jan 18, 2011 7:48 pm Reply with quote

Moosh wrote:
Right, so what you're saying is that we would have to explain to them some experiment which would distinguish between left and right, and then they would have to perform that experiment to see which is left and which is right?

How is that not referring to a physical reference? If you have to do an experiment it's physical reference.

(Though don't take that as a criticism of your post, 'cos what you said was interesting.)


I am sorry very my post was not clear. The aliens do not have to do the experiment in order to distinguish between left and right. If they are as smart as I think they are, their scientists would have done these experiments ages ago, so they need only look up their textbooks. These remarkable asymmetries between left and right in the subatomic world are very well known to us and they probably would be to our alien buddy. The only problem I could see if our buddy was made out of antimatter, i.e. we have an anti-alien, but I would think this scenario would be very unlikely.

See, if still interested,

http://nobelprize.org/nobel_prizes/physics/laureates/1957/yang-lecture.pdf

http://nobelprize.org/nobel_prizes/physics/laureates/1957/lee-lecture.pdf

 
Simon Bosher
777157.  Tue Jan 18, 2011 8:02 pm Reply with quote

aTao wrote:
Quote:
Finally if they do not know any subatomic physics, we might explain to them Fleming's left hand rule or some other physics rule which distinguishes between left and right.


Ahh, but.. Fleming's left Hand rule requires the polarity of the magnetic field be defined. Cant do that without pre-defined left and right and electron movement.

The molecule structure is far more interesting since left and right spirals are distinct and dont change handedness with viewing orientation.

But you still need to determine if you are chatting with aliens or anti-aliens?.


I am relaxed about the possibility of anti-aliens (or perhaps not, we might be missing some physics related to CP violation), but if they do exist, I agree with wikipedia

http://en.wikipedia.org/wiki/Baryon_asymmetry

that they are just too far away.

 
Jumper
777165.  Tue Jan 18, 2011 8:15 pm Reply with quote

Over such a vast distance it would probably be best to send the aliens an e-mail.. All you then need to do is the following...

Quote:


As you look at this message


<<That way is LEFT and that way is RIGHT>>


Last edited by Jumper on Wed Jan 19, 2011 2:06 am; edited 2 times in total

 
oudist
777209.  Wed Jan 19, 2011 1:49 am Reply with quote

But for aliens to understand any demonstration of the concepts 'left' and 'right', don't they have to possess first a concept of space?

 
staticstar
779289.  Sun Jan 23, 2011 5:56 pm Reply with quote

I explained left and right in a psychology paper when explaining why left and right is reversed in a mirror but up and down aren't, it's quite simply that left and right are subjective where as up and down are definite.
In terms of explaining this to aliens over a radio making the assumptions that A) We are speaking the same language and therefore B) both have an understanding of the word north (after all, surely all planets have a north)
the explanation quite simply

Whilst facing North the world and objects to the west of you are your left and the world and objects east of you are your right, this turns with you so that when you are facing South the world and objects to the west is now your right and the world and objects to the East is now your left

does that make sense? and I'm sorry but I completly was clueless when reading the previous comments, I'm sure your arguments are much more logical than mine but there's a reason I am studying a "soft" science

 
samivel
779341.  Mon Jan 24, 2011 1:11 am Reply with quote

You're still using a physical reference.

 

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