@wonderofscience

ALT TEXT (this is all off the cuff and I'm typing this on my phone; no ChatGPT, no Google, no nothing; please correct anything I may have wrong here, or worded funny, etc.):

The video shows by demonstration a really cool behavior of objects in motion, understood to the study of physics according to intermediate axis theorem—also called tennis racket theorem, or the Dzhanibekov effect. We see an astronaut spin a T shaped handle that is attached to a control panel, and it unscrews from the panel, as one would expect. Curiously, the handle—which is, unsurpisingly, floating due to this happening in space—continues to spin while facing the same way with respect to the panel as it did initially, only briefly; it then flips around 180° in said direction, such that the horizontal section where it's meant to be grabbed in order to use it, is then facing towards the panel instead of away from it. This orientation then reverses again, and then reverses again, and so on and so forth, repeatedly. Like that weren't enough, it just keeps spinning the same way it was already spun by the astronaut, while doing the other thing that was just described (taken into account that it turns itself around going the other way whenever it does, of course). The reason why this is called intermediate axis theorem is because all objects with mass, while in motion, will always rotate upon whichever axis provides the highest moment of inertia no matter what, unless otherwise acted upon by an outside force; this axis is, of course, the intermediate axis. The reason why this is also called tennis racket theorem is because it is observed while fully affected by gravity, by throwing a tennis racket end-over-end directly upwards: it is physically impossible for it to rotate upon said axis without also rotating upon the axis 90° perpendicular, and it will have already rotated upon the latter to such extent by the time whoever threw it has had a chance to catch it by the handle again, that the net will no longer be facing in quite the same direction it was when it was thrown. The author of this alt text assumes that Dzhanibekov is most likely who first discovered this, or something, although he doesn't remember offhand and doesn't feel like looking it up. He was taught K-12 at home by a former private school teacher and never went to school in a conventional sense, he earned his GED in 2011 at the age of 17, and he has precisely no qualifications otherwise.

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