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Introduction
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Thank-you Charles, for your kind introduction.
My name is David Payne, I am a retired Professional Chemical Engineer, a member of the Victoria Centre of the RASC, and author of the aprealspace.com website.
One of my passions is taking and processing astrophotographs, and then scientifically interpreting them to figure out what is going on out there.
I’d like to thank RASC for this opportunity to talk to you today, and take you on a quick tour of how, by applying scientific principles, we can deduce how stars are REALLY made from molecular clouds.
Opening
The first image I would like to show is of a seemingly non-descript portion of the sky in Cepheus. All you see is some stars in what appears to be a vast emptiness.
Astrophysicists are adept, both in precision and accuracy, at predicting star, planet, and spacecraft movement. They typically use an n-body simulator to solve ordinary differential equations representing body spacial positions over time as pushed by normal forces.
Stars separated by Space
But stars are only part of the story in space, what you don’t see is that there are gases that fills all the space that is out there. It is in fact, built right into the definition of what a gas is.
(Note that dark matter is considered gas which is likely what it really is in my mass consideration. Any way you look at it, stars are less then 10% of the Milky Way)
Filled with Gas
Our simpleist picture of what a gas is lies in the ideal gas model. We call it “ideal” because no real gas behaves in this oversimplistic way. but it does provide a concept of how a gas behaves – as a collection of particles perpetually moving in random directions with their own kinetic energy.
There are NO forces at a distance – gravity is far too weak and neutral atoms have no net electrical charge.
The only interaction between particles allowed in this model is the instant, elastic repulsion felt when two particles collide and bounce off in new, different directions.
Such collisions are the be-all and end-all of an ideal gas –it is collisions that don’t just allow us, but indeed force us, to group the atoms and molecules and treat the gas as a continuum body with not just statistical, but real, measurable, physical properties, instead of trying to treat them individually.
Temperature is the average kinetic energy of the particles while Pressure is the force that is created by particle collisions on one another and the walls of the container. They are related to one another through the ideal equation of state that says pressure is equal to particle density times temperature.
Astrophysicists have a love/hate relationship with gases. They realize that they need to model gas, but hate gas because mathematically it comes with an entirely different kind of equation to solve that breaks both their simulator and conflicts with many of their theories.
Idealized Model
I too have a problem with an ideal gas because it is impossible to actually make a star out of it.
To make a star we must compress the gas particles into a very tight space.
The problem is that the harder we push, the harder the gas pushes back by pressure and temperature. It’s not that progress can’t be made, it is just that as we make progress it becomes even harder to do the work and there is no-one around to do it – just like emptying the dishwasher.
Finally, once we are finished pushing, we need a star sized container to keep the star from re-expanding, and we don’t seem to have a one at hand – maybe its in the dishwasher.
Any way we look at it, we find that there is something wrong with this ideal gas model, and we must fix it to progress.
The astrophysical approach is to say that the particles are too small and too far apart to collide to gets rid of this work problem. Astrophysicists further argue that gravity can overcome the original pressure and spontaneously collapse simply by making the gas body big. I’m just going to leave both these really bad assumptions alone for now.
Instead of this astrophysical unicorn, I am proposing here that we take a scientific approach and substitute real gases, and real matter for the idealized one. This will bring the full range of nature’s behavoir to bear on the problem.
Making a Star from an Ideal Gas
Thank-you Charles, for your kind introduction.
My name is David Payne, I am a retired Professional Chemical Engineer, a member of the Victoria Centre of the RASC, and author of the aprealspace.com website.
One of my passions is taking and processing astrophotographs, and then scientifically interpreting them to figure out what is going on out there.
I’d like to thank RASC for this opportunity to talk to you today, and take you on a quick tour of how, by applying scientific principles, we can deduce how stars are REALLY made from molecular clouds.
Opening
