Exploration is what humans do. We have explored the entire Earth; now it's time to colonize the moon and establish a human presence on Mars.

So said planetary scientist Jeff Taylor, astronomy professor at the University of Hawaii and the 2008 recipient of the Carl Sagan Medal for Excellence in Public Communication in Planetary Science, during his public lecture "Lunar Settlements, Lunar Science," Oct. 12. He was speaking to a Bailey Hall audience of local space enthusiasts and scientists visiting Ithaca for the 40th Division of Planetary Science Meeting.

Earlier, event emcee and "science guy" Bill Nye '77 noted that in the 36 years since astronauts last stepped on the moon, the Cold War, with its spur to space exploration programs, has ended and NASA budgets have declined. Now, he said, it is the responsibility of scientists to lead the way.

Taylor said that paying the cost of getting back to the moon would be made easier by taking advantage of commercial enterprise and global partnerships, like the coordination between the United States and Russia to ferry astronauts to the International Space Station.

The prohibitive cost of launching materials for even a modest "sustained presence" on the moon -- water, oxygen, fuel and raw materials -- would instead require the mining and processing of resources on the moon. Prospecting for extraterrestrial resources has already started, Taylor said. Spectroscopic measurements of the moon from Earth, for example, have indicated the presence of large deposits of iron oxide, which potentially could be processed into oxygen and iron for steel. And craters in permanent shadow at the poles may contain water. "There are 22 ways to extract oxygen from the lunar surface," said Taylor, who also has communicated science through children's books, a novel, a series of educational videos and the Web site Planetary Science Research Discoveries.

But humans need the right attitude, he emphasized. While NASA has increased funding for manned spaceflight for the next two decades, further development of lunar planning would require the help of the private sector. Opportunities for commercial enterprise abound for lunar transportation, communication, agriculture and life support, he said.

In the end, returning to the moon, he said, is about challenging ourselves, fostering a sense of pride and inspiring future generations, as the space race of the 1960s inspired previous generations.

Graduate student David Bernat is a writer intern at the Cornell Chronicle.