So you creationists are so wedded to your Biblical literalism that now you reject all of astrononomy as well as one of the most obviously true tenets of biology? Your argument was made 300 years ago. At that time it was not asinine, as it was widely assumed the Sun burned like coal. Now we know of fusion.
And of course, the size of the Sun has not been been a topic with widely varying answers at least since shortly after it was accepted that the Earth went around it.
What's next in your fantasy universe, a flat Earth?
Possible, but not likely. People like these are into control, so the world would made up of the "Believers" and the imprisoned.
The infidels in prison will be doomed to Perdition, while the Creationists will receive their reward in Paradise of 79 virgin monkeys.
And of course, the size of the Sun has not been been a topic with widely varying answers at least since shortly after it was accepted that the Earth went around it.
What's next in your fantasy universe, a flat Earth?
Surely you are not trying to imply that fusion and the resultant energy release which proceedes from it is somehow afunction of matter spotaneously generating itself without expense! Making Helium from of Hydrogen expends and releases frictional and photon energy, it does not create matter. Is this what forms the basis of your "open system" position? If so, you may wish to refresh your memory with regard to the Laws of Conservation of Matter and Energy, and mass-balance.
The heat which warms our planet and proceedes from the sun should be evidence enough to the junior physicist that energy is expended from a finite energy producing source. The sun does not recapture energy lost to entropy.
Whether one generates heat from burning methane or from a fusion reaction, both systems deplete their inherent mass as energy is released to entropy. As was pointed out to you in the orignal post, the rate of solar burn is able to be measured. The Sun is depleting is resources at a measure-able rate.
By definition the Sun is losing its mass and with it, its size at a measureable rate, and if the rate observed today is the same as the rate that has been, the Earth would be uninhabitable at a fixed point in the past due to the size of solar mass as yet unconsumed. Fusion does not change classical principles of mass-balance. You, like balrog666 might want to write to Starfleet Academy and ask for a refund.
Where "flat Earth" history is concerned, those who promoted it (e.g., Lactantius c. 245-325 A.D. and Cosmas Indicopleustes in the 6th century) were identified as heretics by early Church fathers, and their writings were shelved and decried. Your knowledge of the intellectual history of the church ignores Judeo-Christian scripturual references to the round Earth (Isaiah 40:22), and evidently stretches only so far back as to 18th-19th century myths promoted by novelists like Washington Irving.
It is you whose pretense to knowledge alludes to "history" as imagined in a novelist's "fantasy," not I.