Mathematical crime-fighter helps hunt for alien worlds

A curious mathematical crime-fighter has just boosted our confidence that the galaxy is brimming with alien worlds.

The statistical phenomenon, called Benford's law, has been shown to fit existing data on both confirmed and candidate exoplanets. The results suggest that of the thousands of planetary candidates, the majority will turn out to be real worlds and not errors in the data.

Initially a mere mathematical oddity, Benford's law states that the first digits of the numbers in certain sets follow a pattern of probability. For the numbers in a variety of data sets, 1 is the leading digit about 30 per cent of the time. Higher digits are less frequent: on average, just 4.6 per cent of numbers in such sets begin with 9.

Thomas Hair at Florida Gulf Coast University in Fort Myers wondered if Benford's law would hold true even beyond the solar system. "I became intrigued with the idea that exoplanet mass might fit," he says.

Hair examined data from the online catalogue exoplanets.org, which lists 755 confirmed exoplanets and nearly 3500 planet candidates, many of them found only in the past few years by NASA's Kepler space telescope. Masses are given in multiples of Earth's or Jupiter's mass. He found that the figures closely fit Benford's law for both units.

"The close fit with Benford's law gives a confirmation to experts' belief that most of the candidates are valid," says Hair, who will present the work in January at the Joint Mathematics Meeting in Baltimore, Maryland.

Source: New Scientist