Dear Dr. Bohlin,
As a Christian, how do you view the age of the earth? I was wondering how scientists calculate the age of the stars and the earth.
Please see my article "Christian Views of Science and Earth History" which will give a fuller explanation of my view. Briefly, I am currently undecided or uncommitted to any particular view of the age of the earth. I continue to find the six 24-hour literal day interpretation of Genesis 1 & 2 to be the most convincing, but I find great evidence for long ages for the universe and the earth. Basically I feel that there is not sufficient evidence either biblically or scientifically to decide the issue. We need more time and more data.
The age of the stars is principally determined by what is known as the red-shift. Light from galaxies that are moving away from us is shifted toward the red end of the light spectrum. The farther away the galaxy is the further toward the red, the light is shifted. If galaxies are moving towards us, their light would be shifted toward the blue end of the spectrum. The vast majority of galaxies are shifted toward the red and those which appear to be the youngest also demonstrate the strongest red-shift. There are Christian as well as a few non-Christian astronomers that are critics of this view of red-shifts but the majority find this explanation to be persuasive and authoritative. You may try visiting an astronomy web site from a planetarium for a fuller explanation.