When corals are alive, they deposit layers of calcium carbonate within the coral skeleton. Every day a new layer is laid down, leaving a laminar appearance to the deposit. During the colder months, the deposits are thinner than in the warmer months so it is also possible to determine how many days there were in a year. It turns out that there are consistently about 400 laminations in a year's deposit, which indicates a year was 400 days long. A backup for this is seen in the chambered nautilus, an animal related to the octopus and squid. The nautilus lives in a shell which it builds as it grows. When it gets too big for the shell it is in, it secretes a new chamber on the open end of its shell and seals off the old section with a wall called a septum. The nautilus adds a wall every day so, in a month, there will be 30 septa added. When we look at fossilized nautilus specimens, we find that the older the fossil, the fewer septa per month it has. Ordovician aged nautiluses seem to have had an average of 417 days in a year which means a day was about 21 hours long.
There are many possibilities as to what is causing the earth to slow down. Tidal friction between the oceans and their floors seems to be the best. Measurements of comet orbits shows the earth slows by about .00002 seconds per year and, over very long periods of time, this works out to be about right for the Ordovician aged fossils--which is a good argument that the earth may be considerably older than the traditional 6,000 years.
More important, however, is the fact that this slowed rotation compensates
for the cooling of the sun. If the earth was spinning faster when the sun
was hotter, this would spread out the solar energy absorbed by the land.
As the sun cools, it takes longer for the solar energy to be absorbed because
it is less concentrated. It appears that the rate of slowing of the
rotation of the earth and the rate of cooling of the sun have been synchronized
to keep the surface of the earth suitable for life. While some of the
measurements await collaborative verification, it appears that another
variable has been discovered that had to be carefully and intelligently
designed to allow life to exist. The more things that have to be right,
the less likely it is that life on earth could be a product of chance.
(Data from "Journey into Deep Time," by Edward Greding, Jr., Astronomy, March, 1995, pages 16-18.)
Back to Contents Does God Exist?, March/April 1996