I start with quoting from Wikipedia:
Peggy Annette Whitson (born February 9, 1960) is an American biochemistry researcher, NASA astronaut, and former NASA Chief Astronaut. Her first space mission was in 2002, with an extended stay aboard the International Space Station as a member of Expedition 5. Her second mission launched October 10, 2007, as the first woman commander of the ISS with Expedition 16. She is currently in space on her third long-duration space flight and is the current commander of the International Space Station.
Two weeks ago we could see live how “Kimbrough and Flight Engineer Peggy Whitson of NASA reconnect cables and electrical connections on PMA-3 at its new home on top Harmony”
That is surely fascinating, but what we are particularly interested in the spinning top in zero gravity experiments on the board of ISS in 2013
At 0:42 in this video Peggy tells us that:
“Conservation of angular momentum keeps the top axis pointed in the same direction”
We look at it, and we compare with the other video featuring the Dzhanibekov effect
The same effect I have modeled with Mathematica:
is even better visible here:
There is also conservation of angular momentum there, but the axis of rotation evidently is not being kept all the time in the same direction. Once in while, quasi-periodically, it flips.
What’s going on?
The answer is: it is, as Chris Hadfield sings, a Space Odity
Can you hear me, Major Tom?
Can you “Here am I floating ’round my tin can
Far above the moon
Planet Earth is blue
And there’s nothing I can do
Indeed, there are laws of physics and sometimes they are odd. Major Tom can do nothing about it except of just watching:
But no, not exactly. We can do something about it. We can try to figure it out, why things happen the way they happen. Mathematics will help us when physical intuition does not suffice.
And that is our plan for the future. As P.A.M. Dirac wrote it on the blackboard during his lecture in Moscow in 1956:
Physical law should have mathematical beauty and we are watching this beauty while playing with geodesics of left-invariant metrics on Lie groups.
We will be looking into the spinning top – but relativistic one. These relativistic tops fly somewhere in space, but they are not yet mass-produced in factories in China. But soon….
It is all about “attitude”. Mathematically the attitude matrix satisfies nonlinear differential equations, and they have their odities. And, as Chris Hadfield explains it in his book “An Astronaut’s Guide to Live on Earth”:
In space flight, “attitude” refers to orientation: which direction your vehicle is pointing relative to the Sun, Earth and other spacecraft. If you lose control of your attitude, two things happen: the vehicle starts to tumble and spin, disorienting everyone on board, and it also strays from its course, which, if you’re short on time or fuel, could mean the difference between life and death. In the Soyuz, for example, we use every cue from every available source—periscope, multiple sensors, the horizon—to monitor our attitude constantly and adjust if necessary. We never want to lose attitude, since maintaining attitude is fundamental to success.
In my experience, something similar is true on Earth. Ultimately, I don’t determine whether I arrive at the desired professional destination. Too many variables are out of my control. There’s really just one thing I can control: my attitude during the journey, which is what keeps me feeling steady and stable, and what keeps me headed in the right direction. So I consciously monitor and correct, if necessary, because losing attitude would be far worse than not achieving my goal.
3 thoughts on “Spinning Top – Space Odity”
Cool clip. Better than original.
What is the probably cause of the Dzhanibekov effect? Outside the mathematical explonations. After this whole series if you would say with simple language, what stay behind Dzhanibekov effect or what you think behind it, what would you say?
“What is the probably cause of the Dzhanibekov effect?”
Laws of physics like conservation of energy and conservation of angular momentum. Without experience and without mathematics it can be counter intuitive, but it is like learning to ride the bicycle, you can’t learn it relying on your intuition :)
But laws of physics are often misunderstood. Even the standard textbooks have errors. Famous physicists make errors, these errors are sometimes propagated by others.
Nowadays we have internet. It is easier than ever before to spread errors. But it is also easier than ever before to point them out to those who are searching for the truth.
Hmm… a miałem nadzieję, że może coś tu jeszcze “fiknie”, no i… :)
Dziękuję, bardzo ciekawe to było, chociaż ze spraw “technicznych”, czysto matematycznych, nie wszystko mi się udało zrozumieć – mam duże braki, też czasu (w skali makro i mikro), na to, żeby porządnie w to wejść.
Z pozdrowieniami (i nadzieją na następny fajny temat),