Astronomical Odds

Astronomical Odds

Joe Carson, physics and astronomy professor, College of Charleston

Forget the suntan lotion, sandals and shades. When Joe Carson takes a trip to Hawaii, he packs a winter coat. Carson is an astronomer, so that could explain his apparent confusion. His mind is more often out of this world than in it, and outer space can indeed be very, very cold.

Yet there’s a method to this physics and astronomy professor’s madness, and Carson knows that – while his fellow airplane passengers are most likely bound for Oahu’s picturesque Waikiki Beach and Diamond Head State Monument – he’s hopping over to the Big Island for a visit up Mauna Kea. Standing 13,796 feet above sea level, the volcano is Hawaii’s highest point, and its summit is often blanketed with snow, hence the need for that thick jacket. The top of Mauna Kea is also covered in high-powered telescopes, including the 8.2-meter Subaru optical-infrared telescope that Carson uses to take pictures of the stars and surrounding planets.

Like any photographer, Carson says he appreciates the aesthetics of the mesmerizing thermal photos he and his colleagues take. But one would be foolish to dismiss his snapshots as mere pretty pictures. Indeed, when one considers the cosmic consequences of Carson’s work, the effect is mind blowing.

Joe Carson, physics and astronomy professor, College of Charleston

In 2009, Carson was a leader of a team of researchers from Germany’s Max Planck Institute for Astronomy that took an image of what they’re calling a “planet-like object” more than 50 light years from Earth. Though scientists have been discovering planets beyond our solar system for more than a decade (about 400 exoplanets have been found), it’s incredibly rare to obtain a direct image. Usually, these exoplanets are detected indirectly, such as by seeing how a nearby star dims when the exoplanet passes before it.

Yet, by focusing on young planets located a healthy distance from the stars they orbit, it is possible to snap a direct image. Young planets retain more heat left over from their creation, making them more visible when looking through infrared filters. And the farther a planet is from its star, the better the chance it will not be obscured by the immense amount of light being produced by the star.

And so it was that Carson and his colleagues were able to photograph a planet-like object orbiting the star GJ 758 – an achievement Time magazine named as one of the top 10 scientific discoveries of 2009. Carson and fellow researchers are still unable to say definitively whether the object is a planet or a brown dwarf (otherwise known as a failed star), but their achievement was nonetheless impressive because of the very complicated game of hide-and-seek that astronomers and exoplanets play.

The single image of the star and its planet, explains Carson, is actually a manipulation of more than 500 images. In order to filter the images and reveal this potential hidden planet, Carson and a colleague created a complex software program, which he calls a pipeline, to process many images of the same star.

Though half of the stars in the sky are thought to have planets orbiting them, finding proof of other planets beyond our solar system can be a frustrating task, akin to finding a needle in a cosmic haystack. Carson himself has looked at 150 stars and so far found only this one possible planet.

This year, Carson was part of a research team that photographed the birth of a planet system. Such accomplishments, he says, help scientists determine just how rare or common life is on other planets and which planets have the best chances of exhibiting signs of life. Above all, it helps us learn about our own solar system’s history and how we happen to be walking around this earth. For Carson, snapshots of other planets can help answer some of the most fundamental questions.

“We want to understand better where we come from,” says Carson. “How exactly, did our own planet system come to be?”

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