Absolutely Top

How many of us keep the memory of throwing a top with a string wound around?
It would just land on the ground on its tip and keep spinning upright, in front of our marvelled eyes until it eventually started to wobble and finally lie down like an inebriated thing in its erratic path, to be quickly picked up before it rolled away.

The best throwers sometimes raised their spinning tops from the ground on one hand and proudly showed their address around, twisting the hand in an angle so we could see for the thousandth time that the spinning top still kept its original vertical orientation, as if that fact was due to a personal skill.

And we would do it again and again, as the sight of those spinning objects was something fascinating.

Girls also, played this game of throwing toy tops spinning.
But their manner was rather different from boy's.
Having duly coiled the string around the top's belly, girls would half squat bending their knees gracefully and throw it almost parallel to the ground, leaving it spinning at the end of the uncoiled string.
Whereas boys threw it from a standing position in an almost vertical up-down motion.

Results were similar anyway and in the end, everyone had its top spinning.

As we went to school, eventually to some of us the memory of those spinning tops came back under the form of gyroscopes.

Amazing ! When I was a kid I had a toy named gyroscope...

And I've learned a few things at school about my toy top.

It's always a strange feeling when someone desiccates things about which you had a stabilized vision you were happy about. Someone that tells you that your toy has a name. And it has properties.

And it plays a very important role in humanity.
People who do that, they better teach you something you can assimilate and recognize. Otherwise it is preferable to leave you at your basic concepts.
They are called teachers.

I had the chance of meeting people who taught me things I easily recognized and accepted.

Well, finally I was convinced that it was important to know that a symmetric mass spinning around its symmetry axis, tends to keep that axis pointing to a sidereal point, completely independent of any earthly referential.
That is called the rigidity property of the gyroscope. Meaning that whatever orientation it has when it starts spinning it will keep that same orientation if not disturbed.

Far out !
My top would have an extra-terrestrial referential any time I threw it spinning...
And keep the absolute orientation of its axis independently of earth's rotation...
And if you mount it in a two gimbal system, you find out it can stand at any angle as long as it is spinning.
Amazing. (I say this honestly. Not only to punctuate this paragraph).
Once the movement weakens off, it becomes more and more subject to terrestrial laws. And gravity ends by taking the top (so to say) and it wobbles and falls.

And it's the same with mother earth. We're born, live and die on a gyroscope.
The ballerina on the stage... when she spins, she is a gyroscope. hehehe. For some privileged moments, she points to an absolute referential. That should be a thrill for the male dancer whose hands catch her waist.
He stops her absolute moment and rescues her to real life. hehehe.
And electrons spinning, they are gyroscopes too. Well we could keep on this delirium for a while...

But there is at least a second property that goes by the name of precession.
That means that when the gyroscope's spinning axis is pushed in some direction, it responds by moving at a 90° angle from the orientation of the push in the sense of its spin.

Which gives us the possibility of playing with its axis with adjusted forces in alternate directions so as to keep it pointing at a precise point we defined, like North, for instance.
Raughly, this was the kind of top I played with when I was a sailor.

I've been throwing tops all my life one way or another.
So, to borrow the expression from Michel Tournier (a French writer), I had the absolute in my pocket each time I was carrying my top around.