The Sunflower Galaxy and Dynamic Complexities

At first glance, Messier 63 (M63 for short or aka “the Sunflower Galaxy”) appears to be a break from the traditional spiral structure of galaxies and represent a new type of galaxy termed a “flocculent” class. It was thought that the stars formed clumpy clouds gathered together as clumps, like strands of wool form clumps of wool – even on the sheep. In chemical engineering, we often use agents that make particles suspended in a fluid clump together to form larger particles ,so that gravity can overcome the suspension and separate the particles from the fluid. I like to thing that the word flocculate (or its sorter “floc”) comes from the word “flock”, as in a flock of sheep,

Fueling up a New Star – Gravity vs Angular Momentum

In order to grow, a nucleated (condensed), cold star core must accumulate hydrogen as future mass and fuel before igniting to fusion and becoming a full fledged shining star. But there is a problem in the way. Just as the sun cannot accumulate planets via gravity, without some mechanism to shed angular momentum, hydrogen will just orbit the baby star and not accumulate upon it. Viscous drag both dissipates angular momentum and allows hydrogen molecules to accumulate by spiraling down to the star. Unlike a planetary orbit, in a spiral gravity, angular momentum, and viscous drag (friction) are not orthogonal to one another, allowing friction to dissipate momentum as the gravitational fall increases it. Upon arrival at the star, there remains a lot of angular momentum that still need dissipating. Compressed, hot hydrogen forms a metallic core on the star where it creates an electromagnetic magneto – a sort of electric motor. The magneto converts angular momentum into linear momentum that squirts out as jets from the poles. Both mechanisms allow hydrogen to accumulate without spinning the young protostar to death. The jets also advertise to us that star formation is going on and results in beautiful images.

A Bunch of Hydrogen – Galactic Spiral Structure (Part 1)

My first post on this website is the first of five that provide insights into the very misunderstood topic of why galactic spirals are spirals. Here we introduce the two matter ingredients that are necessary to create the structure – hydrogen and a central gravitational structure (a black hole will do). I also introduce the concept of self-gravity via Newton’s Shell Theory – and why a “collapsing molecular cloud” neither explains a galaxy, nor even star formation. Also introduced, is the concept of thermodynamics and how two forms of the same material (hydrogen) makes galaxies even more interesting,