The physics department held an exciting seminar on Wednesday.  John C. Armstrong presented about the possibility of habitable planets outside of the solar system.

Armstrong, a physics professor at Weber State University, recently returned from a sabbatical in which he further studied the possibility of “Earth-like” planets in the Milky Way galaxy.

In a 2012 study, each star, of about 100 billion in the Milky Way galaxy, is estimated to host, “on average,” at least 1.6 planets. Armstrong explained that 837 such exoplanets have been identified and confirmed as actual planets, a few of which share striking similarities in size and orbit, among other factors, with Earth.

The real question lies, however, in the existence of surface liquid water. The discovery of exoplanets, particularly those that orbit in the habitable zone where it is possible for liquid water, and therefore life, to exist on the surface, has also intensified interest in the search for extraterrestrial life. Thus, the search for extrasolar planets also includes the study of planetary habitability, which considers a wide range of factors in determining an exoplanet’s suitability for hosting life.

Armstrong also explained that the field of exoplanets is exploding, with new discoveries being made on an almost daily basis, and that the task now is to determine if any of these new worlds are habitable.

“Our effort is to characterize exoplanets and explore how changes in the orbital environment of the planet — such as dramatically altering its tilt — can increase the range of habitability,” Armstrong said. “These ‘tilt-a-worlds’ represent new potential abodes for life in the universe.”

Armstrong taught that orbit, climate, tilt and atmosphere are just a few of the things that are intensely studied when searching for new exoplanets.

“Once a planet is in the habitable zone, there are many other factors that affect it,” Armstrong said. “Orbit depends on the whole structure of the solar system; you not only need the right tilt, but the whole solar system must be set up perfectly for a habitable planet.”

Those who attended the seminar also learned that an additional 2,321 possible exoplanets exist, but that they must be observed for decades in order to confirm them as actual exoplanets.

Armstrong closed with a touch of humor, talking about the nearest exoplanet that might be habitable.

“The nearest confirmed exoplanet to us is Gleesa 5667cc,” Armstrong said. “It is only 16 light-years away and has almost the right temperature, so in a pinch, if the world was coming to an end, that would be our best option.”

David Rogers, a student who attended the seminar, said it was well worth his time.

“I am glad I came,” Rogers said. “It was very interesting to learn about the possibility of other habitable planets. Our Milky Way has always interested me, and I try to learn as much as I possibly can about it.”

Erich VandenBosch, another WSU student, said he learned a lot.

“It’s always fun to hear about the possibility of life somewhere else in the universe,” VandenBosch said. “I also learned quite a bit today and think it is pretty neat how we’re going about studying exoplanets. It’s pretty cool that there are so many sun-like stars out there with planets orbiting them.”

The majority of the seminar focused on how to study whether or not a planet is habitable.

The whole habitable zone is focused on water, Armstrong said, for no other reason other than the fact that people like water. Most planets found are larger than Earth; however, that might only be because the smaller planets are easily overlooked. Neptune-sized planets are the most common planets found, with Jupiter-sized planets being a distant second.

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