Do Comets Indicate the Age of the Solar System?

Kohoutek 1974 (NASA)

The existence of comets has long been used as an argument for a recent creation (probably the best treatment so far is that of Slusher). The case is usually made as follows. The standard model of a comet is one in which all of the material observed is released by an icy nucleus only a few kilometres across. This model strongly suggests that comets are very fragile, losing much of their material during each close pass to the Sun. Most comets follow orbits that take them vast distances from the Sun. If a comet’s orbit takes it too far from the Sun, then the comet could easily be captured by the gravitational attraction of other stars and thus would be lost to the Solar System. This places a maximum distance from the Sun that a comet may orbit. If this maximum distance can be estimated, Kepler's third law of planetary motion can be used to deduce the greatest possible orbital period that a comet may possess (about 11 million years). When combined with an estimate of how many trips around the Sun that a comet can survive, we can estimate the maximum age of comets. This figure is far less than the adopted 4.6 Ga age of the Solar System. Because no source of creation for comets has been identified, comets are assumed to be primordial. If this is true, then the age of the Solar System must be less than the estimated upper age of comets.

Read the rest of "Comets and the Age of the Solar System" here, Howie.