Post Author: Bill Pratt

Some in the evangelical community dismiss the science that shows the universe is old (almost 14 billion years), and I think partly because they never considered the reasons why scientists make this claim.

I am not a physicist or an astronomer, but I am an electrical engineer, so I had to take physics classes in college and gain an understanding of physics in order to practice electrical engineering.  I am going to present some reasons the universe is old, but I cannot get into the details of it.  These reasons are taken from Hugh Ross’ book, A Matter of Days.  I am hoping that this post, and the next, will spur some of you to do more research on the topic.

The first method physicists use to calculate the age of the universe is to measure the expansion rate of the universe.  The universe is growing larger (like a balloon expanding by someone blowing into it), and if we can measure at what rate it is growing, we can calculate how long ago the universe came into existence.  We can mathematically reverse the expansion until the universe reverts back to a singularity, a point so small the human eye cannot detect it.  This is the beginning of the universe.

The way the expansion is calculated is by measuring the distance from other galaxies to us, and observing how fast these other galaxies are moving away from us.  If we know the distances and velocities of enough galaxies, we can calculate the expansion rate of the universe, and thus the age of the universe.

The second method physicists use to calculate the age of the universe is to measure the cosmic background radiation temperature.  When the universe came into existence, it generated a lot of heat!  Ever since that creation event, the universe has been cooling down as it ages.

When we measure the cosmic background radiation (“take the temperature” of the universe), the readings indicate that the temperatures all around us are about -455 deg F (only 2.725 deg C above absolute zero) and vary little – less than 1 part in 10,000.  Given the geometry of the universe and these temperature readings, physicists can calculate how long the universe has been cooling, and thus the age of the universe.

In the next post, we will look at two more methods for determining the age of the universe.  I hope you’ll stick around to learn about them.