WASHINGTON — Enceladus, a small moon of Saturn, has been named the most likely place to find life in the Solar System by researchers at the University of Puerto Rico at Arecibo.

The moon, with a geyser of water blowing into space from a fissure near its south pole, was selected based on a complex “quantitative habitability theory” developed by biophysicist Abel Mendez at the university. The life on the moon would likely be microbial, but given the moon’s distance and the difficulty of getting to the subsurface, it will be a very long time before the prediction can be tested.

Mendez’s approach to determining the habitability zones where life might be found was presented at a meeting of the American Astronomical Society in Puerto Rico earlier this week and is attracting the attention of the scientific community because of its quantitative method of defining where life could be.

The search for habitable environments in the universe is a priority for NASA’s Astrobiology Institute, and Mendez’s approach is important because “it provides an objective way to compare different climate and planetary systems,” said Chris McKay, a planetary scientist at the NASA Ames Research Center in California.

Mendez noted that in his theory, “Enceladus resulted as the object with the highest subsurface habitability in the solar system, but too deep for direct exploration. Mars and Europa [a moon of Jupiter] resulted as the best compromise between habitability and accessibility.”

When Mendez applied his habitability criteria to Earth, he found that during the late Cretaceous, about the same time dinosaurs went extinct some 65 million years ago, our planet had a higher habitability rating than it does today. Then, scientists believe, a large asteroid or comet hit, and that was the end of both the dinosaurs and the high habitability rating.

This article was provided by Inside Science News Service, which is supported by the American Institute of Physics, a not-for-profit publisher of scientific journals.