Spring 2019 - Articles

An Endless Question

By February 19, 2019 No Comments
Comet 46P/Wirtanen

SINCE HE WAS OLD ENOUGH TO DO SO, Dr. Dennis Bodewits had always been asking questions. “How does this work? Where did this come from? What’s a black hole?” They often drifted toward space thanks to his dad, who grew up in the sixties and was fascinated by the moon missions.

“My parents took me to planetarium shows, and my dad even hooked me onto science fiction literature,” said Bodewits.

Today, the Auburn University astrophysicist and associate professor still asks questions, but as science answers one, more arise.

For the last several months, he’s led two campaigns with the Hubble Telescope to observe 46P/Wirtanen. First discovered by astronomer Carl Wirtanen in 1948, it is the tenth-closest fly-by in modern times, roughly 30 times the distance to the moon. The proximity offers what he calls “a space mission in reverse.”

“Comets are leftovers of planet formation,” Bodewits said. “From earth, we can only observe the gas and dust surrounding the nucleus, rather than the nucleus itself, because it’s so small.”

During the December campaign, Bodewits and colleagues combined the Swift, Hubble and Chandra Telescopes to acquire a complete picture of the comet.

The second campaign — continuing through 2019 — will compare Wirtanen’s chemical composition to similar research from the Deep Impact and Rosetta missions in 2004 and 2005. Understanding the connection between the cloud surrounding the comet and its surface remains a key focus of study. No two comets are the same and where the comet ‘grew up’ affects the different chemical properties, Bodewits said. “Those differences tell us about the distribution and types of gas that were present when the planets formed.”

Yet one age-old question persists: Were the comets formed this way, or did they evolve over time?

“Are we looking at a property from the time of the solar system’s formation? Or is there some reaction that’s changing the properties and are we being tricked into looking at it as a whole?” 

As Bodewits continues searching for answers, he isn’t finished asking questions. Despite the apparition, Wirtanen is still only a fly-by amassing nearly 7,000,000 miles between the human hands and itself. But what if it wasn’t?

In a proposal to NASA’s New Frontier’s program, the team suggested building an unmanned space craft called ‘CAESAR’ to fly to comet 67P/Churyumov-Gerasimenko and bring back up to a kilogram of material to Earth. Complicating the venture is the extensive preparatory time, still-needed research and the difficulty of finding a way to reach an object rambling through space. Yet Bodewits remains focused on the questions.

“One of our main ones is where does the water come from? How much water was there in the solar system and how does complex chemistry form? Finding all these things in the molecules and atoms we get from the comet we bring back would help us answer those,” said Bodewits.

The proposal has reached the second round, but the mission wouldn’t launch until 2024 or return until 2038 if approved. Yet time is relative when questions persist and Bodewits will continue asking them.

Bodewits at the Discovery Channel Telescope at Lowell Observatory