Lizzy & Mark: Week 12

Lizzy's update

​As Mark mentioned in his update this week, the tetrahedral collapse model is still in the works.
In case you don’t recall what the model is supposed to demonstrate, here is a diagram of large-scale structure in the universe that labels some of the parts. The unit shows is a megaparsec, to give you an idea of scale, single parsecs are used for measurements within the Milky Way, whereas megaparsecs measure objects and structures much larger.

Here is a little sketch I made for my own understanding of what we’re trying to create:

The filaments are modeled by triangular prisms shown in blue, green, orange, and purple, the node would be in gray (if it wasn’t so obscured). The idea is that the central tetrahedron collapses in on itself and inverts, demonstrating a 3D twist fold. This requires that one or more of the filaments spins in an opposite direction than the others. The idea behind the 3D twist fold is essentially that it “generates structure” The model is of practical use in identifying and accurately measuring galaxies as well as mapping the Cosmic Web and arriving closer to an accurate model of the early Universe.

But all practicalities aside, the impact of advanced physics research often seems lost on the public. Perhaps an outstretched hand is all that is needed to invite the public into this world. Sometimes all it takes is an easily digestible model, maybe one that is scientifically impractical, for the public to get up to speed with current research. The effects of the work may never directly impact their lives, in other words, it won’t put food on the table, but their worldview can be richer for them knowing just what their fellow humans are working on. It takes a mutual understanding for disparate parties to communicate, a common language, a common goal. Art is one of a few universal languages, and truly offers one of the best bridges between the worlds of high science and layman. A work of art can to speak to a viewer in a hundred languages, some of which they may be fluent in, others which their peers and neighbors may know. In that way, a work of art can be a Rosetta Stone for different walks of life to use to understand each other, for science to connect with the world at large.

Until next time, happy holidays all! I know I'm looking forward to the return of longer days. ​

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​Mark's update

I did succeed in 3D-printing some 3D gears in the department where I work at Durham University (like the video below). It is very cool, and clarified to me how the gears work. But the actual gears we would use will have to be modified, unfortunately. In the model as in the video, turning one of the large corners of the cube moves the other large corners in the same direction (looking down at each corner). In the "tetrahedral collapse" model that describes the formation of a galaxy, though, the filaments coming off of a forming galaxy cannot all be going the same direction; there's a curiously simple yet obscure law that they obey: the sum of the cotangents of the 4 rotation angles of filaments around a galaxy equals zero.

It occurred to me that a rather simple modification of the model in the video would represent tetrahedral collapse better. This change would involve removing 3 of the 4 small gears, so that one of the large gears is in direct contact with the other 3 large gears -- that way, 3 of the large gears would rotate the same direction as seen looking down onto the cube, and the 4th would rotate in the opposite way. This would only require modifying one of the parts (not really worth explaining in detail, since even I wasn't really sure how the thing, designed by someone else, worked until I manipulated it personally), which I hope to do while I'm in the US for the holidays ... Hopefully, in investigating this design, I can gain some insight into the scientific model, as well.

Happy holidays, everyone!