Are we alone in the universe? It is a question that has perplexed mankind for centuries — and now two Yale scientists are part of the latest NASA search for the elusive answer.

Earlier this month, NASA launched the Kepler Mission — a robotic probe capable of finding Earth-sized and smaller planets around other stars in the Milky Way that may support extraterrestrial life. Among those involved in the NASA project, which is the first of its kind, are two Yale Astronomy professors, Sarbani Basu and Pierre Demarque.

The Kepler Mission’s probe, a spacecraft that weighs one ton, will spend 3 1/2 years surveying our region of the universe in hopes of locating terrestrial planets — hotspots with optimal temperatures to host liquid water and therefore potentially support life. In addition, the mission also aims to lay the groundwork for future exploration by mapping out new areas of exploration and identifying planetary bodies most likely to contain life.

The probe consists of a 55-inch diameter telescope, which also acts as a 95-million-pixel digital camera. Over the course of its mission, it will record the luminosity of 100,000 stars in the constellations Cygnus and Lyra every half hour, searching for signals that suggest a planet has crossed in front of its star.

Basu is among a group of scientists involved with Kepler investigating not Earth-like planets but the host stars themselves. Building upon years of research into the behavior and structure of stars, Basu is studying what she terms the “ancillary science” of the properties of the host stars that provide light and heat to the planets Kepler is attempting to locate. In particular, she will head the group studying the asteroseismology, or internal structure, of stars in clusters using data recorded by the mission’s probe about their pulsation frequencies.

“Stars like the Sun pulsate constantly and the frequencies with which they pulsate are determined by the structure of the star,” Basu said. “Pulsations of a star produce light variations too, so data from Kepler can be used not only to detect planets, but also to determine stellar pulsation frequencies.”

Demarque, the Munson Professor Emeritus of Natural Philosophy and Astronomy, will use the data generated by the space probe to further his own research on the theory of stellar evolution. Demarque has spent the past 40 years seismically probing the interiors of stars, which allows scientists to model their internal structure.

Much of his research has thus far relied on theory, but the Kepler Mission will offer Demarque a rare opportunity to apply his hypotheses.

“Much of astrophysics, such as the ability to determine stellar ages, is based on stellar evolution theory,” Demarque explained. “The mission will provide the means to study the propagation of sound waves deep in stellar interiors and to probe directly regions whose structure has so far been inferred from physical theory.”

While the Kepler Mission was launched less than three weeks ago, there are already high expectations about its possible outcomes. Basu said she hopes the data collected by the mission’s probe will shed light on current theories of stellar evolution.

Demarque said the mission has the potential to be “truly historic” should Earth-like planets orbiting other stars be located.

“The search for earth-like planets is a major step in understanding humanity’s place in the Universe,” he added. “I expect the next few years to be very exciting.”

The probe is currently just over a million miles from Earth and the first set of data it has generated is already being analyzed by NASA scientists, Jim Fanson, project manager for the Kepler Mission, said. The mission will take at least three years to complete.