Worlds revolving in Hanover and beyond

by Andrew Sosanya | 4/12/17 2:20am

Dartmouth’s physics and astronomy department is conducting ground-breaking research that seeks to understand the cosmic wonders of space.

Assistant professor of physics and astronomy and West House professor Ryan Hickox’s research group tries to answer the mystery about the origins of and physics behind black holes. Along with his group of researchers, comprised of post-doctorate fellows, graduate students and undergraduates, Hickox uses a variety of technological tools to survey the galaxy to uncover the truth about black holes.

“We use pretty much every kind of telescope there is in the world,” Hickox said. “It’s pretty fun.”

Once it gets to the telescope, Hickox’s group uses quasars, or bright black holes, to analyze the growth of galaxies. Hickox said that quasars shine brighter than the all the stars in the galaxy because of the heat from extreme friction from all the mass caving in.

“It’s like a census,” Hickox said. “Take an image of the sky in many different wave lengths, look for the signature of the galaxies and then you try to piece together exactly where the black holes are growing.”

The astronomy department, while rather small, has access to an immense wealth of resources, namely the deeply-coveted observational time with the South African Large Telescope in South Africa and the MDM observatory in Kitt Peak, Arizona. Through the Weed Fund, sponsored by Jay Weed ’80 Tu’82, the department also allows an undergraduate to use the telescope for research.

Christine Black Gr’17 researches supernovae — exploding stars — up to a year after they explode. For Black, waiting some time after the explosions is crucial because the star’s inside becomes clear, and she can work backward to analyze it.

“We don’t actually know how stars explode,” Black said. “We don’t know the physics because we can’t see the inside.”

Black also helps coordinate the weekly public observing nights, where anyone can come to the observatory and look at the night sky. On these Friday nights, graduate and undergraduate students run the observatory and operate two 12-inch telescopes.

This month, observers with an ordinary telescope can clearly see Jupiter aligned with four of its largest moons and Saturn next month.

In fact, observers looking to admire the beauty of the sky can use JSkyCalc, a program developed by physics and astronomy department chair John Thorstensen that became the standard for planning observations. Thorstensen released the widely-used software for free in 2008.

Over the course of his 37 years at Dartmouth, Thorstensen has mainly focused on researching cataclysmic binaries ­­— double stars that orbit each other and eventually explode. Thorstensen uses SALT, the MDM observatory and even the Hubble Space Telescope to observe the orbits of the binaries, which hold the key to a deeper understanding of these stars.

“The time it takes to do that is the single most important parameter you can measure,” Thorstensen said.

One of the most interesting aspects about Thorstensen’s research is the ease of producing a wealth of new information.

“You can measure something interesting — that nobody knows — with a relatively small telescope in a small amount of time,” Thorstensen said.

Thorstensen accompanies students on the astronomy foreign study program in South Africa, one of the hidden gems of off-campus programs at Dartmouth. In Cape Town, where the sky is crystal clear and unobstructed by city lights, students can use the largest telescope in the southern hemisphere.

“The revelatory thing for most students was to see a really, really dark sky with the Southern Milky Way and Magellanic Clouds,” Thorstensen said.