When we look out at the universe we see galaxies much like our own… billions of them. The stars in these galaxies shine just like the stars in our own galaxies. They are made of hydrogen gas, and we can measure the brightness of hydrogen gas in the laboratory, and the brightness of our Sun, so we know how bright many of these stars are as well. The nearby Andromeda galaxy looks virtually identical to our own Milky Way galaxy. We can measure the size of these galaxies and compare them to our own, and get good agreement. The size of the disk of our galaxy is about 100,000 light years across,

Not too bad so far. This is operational science so we would agree for the most part.

which means it takes light about 100,000 years to travel the distance across our galaxy.

Herein lies the problem: assumptions without basis. Please see the response in Reason 7 for a fuller treatment which shows the fallacies in this type of thinking.

When we observe the Andromeda galaxy we observe it to be 2 million light years away, meaning the light took 2 million years to get to us. There are many ways we can determine the distance to this galaxy. With large telescopes we can resolve almost all of the stars in the galaxy. Counting them up, we get about 100 billion stars. If it were not 2 million light years away, it would outshine anything else in the night sky. If this many stars were located within a distance of 6000 light years, the distance light can travel in 6000 years, our galaxy would be overwhelmed with stars. Moreover, we can observe galaxies that have collided. The time it takes for two galaxies to collide is over 200 million years. The evidence goes on and on and on.

Remember that light years are a measure of distance, not time. Apparently this argument attempts to insinuate that we believe the stars are only 6,000 light years away. A simple review of the many articles on our website would show this to be a straw man argument. Nowhere have we made the incorrect statement that all the stars are within 6000 light years! That would be an absurd position to take, actually. This is another attempt to point out the alleged issue of light travel time. There are a number of great theories proposed to handle this using a creationist cosmology. Plus, they again fail to mention their own light travel time problem as mentioned in our response to Reason 10 previously.

Stars, too, give us a very good handle on the age of the universe. We know precisely the physical processes that power stars; we have recreated them here in laboratories on earth with nuclear fusion and fission. As a result, we can use the known laws of physics as measured here on earth to predict the rate at which stars evolve, and the temperature density profile inside stars such as our Sun. We can then measure these properties by observing the light coming from the sun, and they agree precisely with our predictions. We can even measure particles called neutrinos coming from the center of the sun that are produced in nuclear reactions in the sun’s core, and their energy distribution and the number of neutrinos emitted agrees precisely with our calculations.

The processes that power stars are part of operational science. Such science depends on the uniformity of nature, which only makes sense in light of the biblical God. It seems strange from an evolutionary perspective, where everything changes over time, to assume that laws of nature wouldn’t change. To assume laws of nature don’t change is a biblical assumption so you are borrowing from the Bible to even try to do science. At any rate, the temperature profile of the sun is perfectly consistent with its creation about 6,000 years ago.

Based on such predictions we know precisely that the Sun, for example, is 4.55 billion years old (more on this later).

Actually, the fact that the sun is powered by fusion is not relevant to its current age. By estimating the amount of fuel available, and the rate at which it is expended, we can put an upper limit on the age of the sun, but that is all. In other words, a sun-like star can probably run for about 10 billion years before running out of fuel; but how is this rationally relevant to its current age? Although the solar core composition would change with time, current helioseismology technology is not able to penetrate the solar core. Only neutrino data can probe the core; such data only tell us that the core is hot and is apparently fusing hydrogen.

We can also determine the ages of other stars in this way, and the ages of stars in our galaxy tell us that our galaxy is about 11-13 billion years old, precisely in agreement with the number we get from measuring the cosmic microwave background radiation as described above.

Again, our current understanding of stellar processes can only put an upper limit on ages. By the way, the upper limit on age for the hottest blue stars is around 1 million years; so these stars must be younger than this. This certainly agrees with the biblical teaching that stars are only thousands of years old. http://www.answersingenesis.org/articles/2007/05/31/reason-nine-stars