High-speed imaging: Science that might just save the world

Three student members of Dr. Philip Choi’s research team pose in front of the remote sensing equipment. (Chris Nardi • The Student Life)

Films like “Armageddon,” “Deep Impact,” and the aptly named mini-series “Asteroid” all tell the fictional story of a deadly asteroid impact.

In reality, the chance of an asteroid impact is slim. However, Philip Choi, Pomona College professor of physics and astronomy, has been paying more attention to that chance.

“There’s actually a pretty growing group of people who are becoming more and more concerned about the possibility of an asteroid impacting the Earth,” Choi said. “It’s always been one of these things that, well, if it happens it happens.”

A 2018 report titled the National Near-Earth Object Preparedness Strategy and Action Plan concluded that there is much to be understood about near-Earth objects, like asteroids.

Choi and his team of undergraduate students are currently conducting blind asteroid research, in collaboration with the NASA Jet Propulsion Laboratory, that focuses on developing scientific techniques to better detect asteroids.

The project is a near-earth search, so the asteroids the team is identifying have never been detected before.

“A lot of the studies you’ll do for asteroids will go and observe and track known asteroids, study their composition, study their trajectory, all those kinds of things,” Choi said. “This project is very different in that the astrophysical is somewhat secondary to the discovery of new source sources.”

To find objects in the night sky, Choi’s team utilizes a 1-meter telescope at Table Mountain, a JPL research facility about 20 minutes north of campus.    

“We have been running up there for around 20 years now, and our project is in collaboration with JPL scientists who are providing instrumentation for our telescope,” Choi said.

Normally, astronomers will capture an image of the sky and look for objects that streak across the picture. Choi’s team is taking a different approach. To observe and capture objects, Choi’s team uses a technique called high-speed imaging, where they capture short videos.

“The field of astronomy is usually interested in observing deeper, fainter, and more distant objects,” Choi said. “As you get fainter and fainter, those streaks are impossible to see because they are so faint. What we’ll do is we will take a video of the sky and then we’ll process that video and look for moving objects.”

The project is unlocking new information. As Choi described, in the past, astronomical research often did not take into account the time variability of distant objects.

“Time variability often gets washed out when you just sit and stare at something,” Choi said. “Generally, the time-scale of variation we’ve started studying has been hours to days to years.”

High-speed imaging of distant objects brings the timescale rate down, and Choi’s team is now able to measure objects on time-scales of seconds.

“So that’s the thing that is most interesting about this project. Beyond just saving the planet, we’re exploring a part of this parameter space that has historically not been explored before,” Choi said.

Beyond asteroids, this high-speed imaging technique is currently being used in projects related to observing objects located at the edge of our solar system and understanding the environment around supermassive black holes.

Student researchers are the backbone of this project, and Choi has had over a dozen students work on the project over the last three years.

“All the data is being acquired by our undergraduate students,” he said. “In any given semester, I will have four or five students who will observe for a few hours every night to try and build up a data set that then gets passed along to JPL. They’ll go and look for detections. If they find something, they’ll send it back to us and we’ll do follow-up of that object.”

Many of the students have been working on the project since they stepped foot on campus.

“These are first- and second-year students who have been involved in this project from the very beginning,” Choi said. “To me, that’s one of the biggest highlights.”

While we may not be fully capable of thwarting an “Armageddon” level asteroid impact, this research will prompt better tracking and understanding of asteroids.

Choi explained how the research is helping: “We have started monitoring the sky well enough that we are starting to see things maybe a day before they might impact us. It doesn’t give you much time, but we’re getting better.”

D’Maia Curry is a geology major at Pomona College. She loves dancing, reading, and looking at really cool rocks.

 

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