Since the time of the ancient Greeks, humans have wondered if we're alone in the universe. Technology has finally evolved enough to reach out into the cosmos for an answer to that question.

Jason Steffen, who is doing post-doctoral research at the Fermilab Center for Particle Astrophysics and who earned his undergraduate degree at Weber State University, visited the Clark Planetarium to share the early findings of the Kepler Mission with a sold-out crowd Monday night of more than 200.

"The compelling question is how many Earths are there to date? We don't know that answer, but Kepler is out there to find the answer to that question," Steffen told The Tribune .

The NASA-funded mission is looking at a small section of the sky in the Cygnus constellation. The satellite will monitor 150,000 stars, and scientists hope it can monitor dim periods in the star that might indicate a planet is crossing in front of it.

From there, data is transmitted to Earth and scientists eliminate other possibilities, such as binary star systems or other anomalies, Steffen said. In just the first few months of data, five planets have been found, but all are significantly larger than Earth and are probably gas or ice giants as opposed to Earth-like.

Data, though, will continue to pour in from the Kepler Mission for at least 3½ years, and it is sensitive enough to find roughly Earth-sized planets. A future mission could then analyze individual planets to determine if it could support life, meaning water could exist on the surface.

However, the odds of finding planets of any size, and especially ones the size of Earth, are seemingly astronomical. Scientists expect to find only a few hundred planets because of the satellite's limitations and the amount of stellar noise that makes it difficult to determine a planet from some other celestial object.

"If we end up not finding anything at all, that too would be very significant because it would show that our planet is very rare," Steffen said. "In that case, we'd be even more grateful for what we've got right here."

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