One of the crucial tests in science (or any field, for that matter) for the validity of a theory or explanation is how well it stands up to the test of time.
As more evidence is gathered, does this evidence support the theory (requiring only minor modifications), or does the evidence undermine key elements of the theory such that it is best abandoned altogether.
This testing—a cornerstone of Reasons To Believe’s creation model—is a vital step in evaluating both the facts of nature and our interpretation of the words of the Bible. It is our contention that as more discoveries are made, these two areas of knowledge will completely harmonize with each other, and we will see, in particular, a growing body of evidence supporting the uniqueness of life here on Earth.
RTB has recently reported (skip down to the August 29 entry) on various research papers that established the importance of Jupiter as a protector of Earth from long-period comet and asteroid collisions. This protective position has also been one component of the Rare Earth hypothesis as espoused by Donald Brownlee and Peter Ward in their book, Rare Earth. The idea is that without a Jupiter-sized planet in a solar system, any earth-like planet would suffer too many collisions to provide a long-term safe haven for advanced life.
Not surprisingly, however, not every discovery will appear, at least on the surface, to provide evidence for the uniqueness of our solar system. A recent report presented at the European Planetary Science Congress in Potsdam gave results that seem (at present) to contradict RTB’s model. This new study by Jonathan Horner and Barrie Jones of the Open University in the UK shows that for the class of comets called the Jupiter Family of comets (JFCs, which are short-period comets), the presence of Jupiter in the solar system does not necessarily reduce the number of impacts on Earth. This discovery contrasts with earlier studies based on long-period comets. In fact, the recent study showed that “no Jupiter” results in the same number of hits to Earth as does a solar system with a Jupiter. And, a Jupiter half its present size actually increased the number of hits to Earth. This work is based on a computer model that tracks the paths of 100,000 JFCs over a period of 10 million years.
Some astronomers conclude that these results damage the case for the Rare Earth hypothesis. However, this judgment is perhaps a little premature, since it is ultimately the asteroids and larger long-period comets that provide the greatest threat to life on Earth.
Before we jump ship on the importance of a Jupiter-like planet for a life-sustaining planet, RTB would like to see the Horner and Jones study expanded to include the effects from these larger objects and, simultaneously, the effects of the other gas giants in our solar system. It is our belief that when all the variables are taken into account, Jupiter-like planets will prove to be critical for Earth-like planets to sustain life.