We are all familiar with the standard models of star evolution and development that say that stars of certain sizes develop along pretty standard paths resulting in black dwarfs, white dwarfs, supernovae, neutron stars and black holes, but what are the percentages of various elements inside the star comparable to its size that produces this effect and what proportions of new elements are produced during this process?
What has struck me as odd is that given the using up and production of elements the proportions seem to be wrong compared to what we think the history is.
If you look at our local galaxy we find that the proportions of the 114 elements are as such:
1 Hydrogen 0.739
2 Helium 0.240
8 Oxygen 0.0104
6 Carbon 0.0046
10 Neon 0.00134
26 Iron 0.00109
7 Nitrogen 0.00096
14 Silicon 0.00065
12 Magnesium 0.00058
16 Sulphur 0.00044
Our galaxy seems pretty typical so we can take this as a base estimation for galaxies in the rest of the universe as far as we know.
Taking our local solar system the proportions change to:
So, we can hazard a guess at the proportions in the universe as a whole based on the general densities of each unit by size and proportion curves:
1 Hydrogen 0.76
2 Helium 0.22
8 Oxygen 0.01
6 Carbon 0.006
26 Iron 0.0011
10 Neon 0.001
7 Nitrogen 0.0007
14 Silicon 0.0005
16 Sulphur 0.00035
12 Magnesium 0.0003
How the universe is taken to have evolved.
We take the big bang as the current theory of how the universe started. Based on this we had sub atomic particles that formed the first element hydrogen. Quite possibly it was sub-sub atomic particles that started out, and we still can’t detect those, only above a certain level. This is what probably all of the primary stars started off with. They were assumed to be super-giants formed out of the clouds of hydrogen that formed. The densities would probably not allow for creation at that point of higher weight elements, needing at least a star to start fusing them. So, we start with very large stars and fusing into helium until at some point they exploded producing a mix of lower end elements. The view is that they use up all of their hydrogen before doing this, but if they did then there wouldn’t be hardly any hydrogen left over except for free amounts not bound to stars. Probably a star needs to go through about 10% of its fuel.
We have the view that stars will go on fusing hydrogen until they run out, then fusing helium until they get to iron and explode, but if this was true, unless there were masses of unallocated hydrogen clouds still floating around, a thing we haven’t seen, given the solar winds of those stars we would end up with very little hydrogen left after one cycle, let alone the number of cycles we have worked out or expected. There would certainly be a lot less free hydrogen to form the next set of stars, so they would be very sparse and few. Also, the view that stars are pretty homogenous as to material is suspect, and the variation that we see and know about show they probably have differing concentration of elements including iron and heavier ones to start with, not just being composed of mainly hydrogen. The problem is time to do all of those things. In an expanding universe the time required doesn’t work out with stars forming more than you would expect for the material to get to the stage, accumulate and get to a position to ignite.
It’s likely that stars use up hydrogen to a point, and reaching that point change and go through various different processes according to density but will not ‘use up’ their hydrogen, quite possibly only converting a very small percentage before that change.
So, this accumulative heavier elements increase in proportion over time, something like our sun being close to a fourth generation star, each preceding star probably taking something like a billion years to form but being proportionally twice as large, and going through their cycle twice as fast. Each cycle enriching the available mix, the stars solar wind pushing out the heavier elements into more stable orbits with local eddies, while attracting those with less profile and cycling in.
This will give values for the heavier elements that we have found. More cycles and there would be more than found, fewer cycles and there would be less than found, current view of suns lives, very little hydrogen, certainly not 76%.
One thing that might bear on the matter is the path a photon takes as it leaves the sun. It’s assumed that it leaves in a straight line from point to point, from the sun’s surface to a point on earth’s surface, but are we sure about that? To test this we would need two satellites orbiting close to the sun, each one equidistant on either side and sending a pulse simultaneously in time.