Stellar Evolution and Millions of Years

The recent article by Jason Lisle made the claim that the Universe is only 6,000 years old, but it also included an illustration of the Hertzprung-Russel [sic] diagram, which demonstrates that the Universe must be at least millions and probably billions of years old. How do you explain the presence of white dwarfs below the Main Sequence when stars that have masses of 0.5 to 1.4 solar masses should all be on the Main Sequence if only 6,000 years old? For these white dwarf stars of approximate solar mass to have exhausted their stores of fusable hydrogen and helium nuclei and now must be held up against gravitational collapse by electron degeneracy pressure, rather than the thermal pressure of nuclear reactions, they would have to be billions of years old. A claim that God created them as degenerate white dwarfs cannot be accepted on scientific grounds, since the H-R diagram clearly shows a progression from Main Sequence to red giants and finally white dwarfs.

—S.K., MD, US

The HR diagram by itself doesn’t really have anything to do with the notion of millions of years. It is simply a plot of star luminosity versus spectral type (or temperature or color). We find that most stars lie along the main sequence, and a fraction of them do not.

Standard secular stellar evolution theories claim that non-main-sequence stars (such as giants and supergiants) are highly aged versions: i.e., stars that were once on the main sequence but have “evolved” due to depletion of hydrogen in the core. It is also assumed that such a process takes a long period of time. Of course, it is worth pointing out that this has never been observed or directly tested—nor could it be, if it really takes millions of years. Therefore, at best, it lies along the lines of an untested conjecture, though perhaps a reasonable one from a secular perspective.

Not all progressions are time-progressions. That is, just because there is a sort of continuity within an HR diagram or between HR diagrams, it does not follow that one is a more aged version of another. In fact, the main sequence itself was once assumed to be a time progression. It was assumed that stars evolved along the main sequence going from blue to red with time. But now it is known that the main sequence is not a time-sequence at all, but rather a mass sequence; blue main sequence stars are more massive than red ones. Stars do not evolve along the main sequence as once thought. But to this day, stars on the blue end of the main sequence are called “early-type” stars and red stars are “late-type” stars—a reminder that we should avoid the fallacy of assuming a temporal relationship where none exist.

It isn’t rational to argue that God couldn’t have created some white dwarfs (or red giants, etc.) at the beginning—even if others really are the result of stellar aging. God created the first trees already bearing fruit (Genesis 1:11–12), and it took no time for this, even though today we see a clear time-sequence by which trees spring up, grow, and bear fruit.

Furthermore, even if we were to grant for the sake of hypothesis that all white dwarfs have resulted from stellar collapse, there is no empirical way to show that this must take millions of years. And there is possible historical evidence to the contrary. Some ancient documents (including Ptolemy’s Almagest) refer to the bright star Sirius as being red in color (today it is blue-white). Sirius is orbited by a white dwarf companion (Sirius B); so, it may be that Sirius B was a red giant in the recent past (overwhelming the blue-white color of Sirius A). If so, the collapse must have happened on a thousands-of-years timescale. Regardless of whether or not this is the case, it is known that rapid changes in star brightness/luminosity do occur.

So, clearly, in light of the above considerations, it would be erroneous to argue that the universe must be billions of years old on the basis of the HR diagram. In addition to all the above caveats, we should also consider the various creation cosmogony scenarios involving relativistic time dilation, such as the ones promoted by Russ Humphreys and John Hartnett. In these models, stars can literally age millions of years while only thousands of years elapse on Earth—in which case the secular conjectures regarding stellar aging may be close to the right idea. Such time dilation is the result of Einstein's physics—the well-tested General Theory of Relativity. This is something you may want to read up on if you are interested in cosmology.