Ben Farr began his astronomy research over 12 years ago and is still passionate for learning about the complexity of galaxies today. Farr works with the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Hanford, Washington, and teaches at the University of Oregon.
His work aims to figure out the depths of the unknown universe with the help of new technology. Gravitational waves, as described by the LIGO website, are “ripples in space-time caused by some of the most violent and energetic processes in the Universe.”
Farr said that the idea of recording the events seemed very unlikely because the detection of ripples would require very sensitive instrumentation. “It’s incredibly precise, and we’re conducting them from the surface of the Earth, which is really difficult to do,” he said.
The science being done with LIGO is meant to determine what could be farther out in the galaxies neighboring the Milky Way. Gravitational waves have been useful in navigating activity in the galaxy; they have been making a bigger presence in new data, Farr explained.
“The distance between objects will grow and shrink as a wave passes through. The LIGO detectors are trying to measure these very subtle changes on the surface of the Earth,” he said. “What causes those distortions are really extreme events, which means the collisions of black holes or neutron stars in other galaxies.”
The team finally built solid detectors to take those measurements in 2015. The first collision that was measured was between two binary neutron stars, which were estimated to be 1.1 to 1.6 times the mass of the sun. A neutron star is 12 miles in diameter and is “so dense that a teaspoon of neutron star material has a mass of about a billion tons,” according to LIGO’s press release.
Binary neutron stars are massive, city-sized stars created by the explosion of another star, according to the Space website .
That discovery was given a Nobel Peace Prize in 2017, as well as recognition for the field of gravitational-wave measurement, according to C&EN news. That recent discovery seemed very different from any other prior in the entire Milky Way galaxy, according to Farr.
“It seems to suggest some other population of binary neutron stars in our own Milky Way galaxy that we’ve so far missed, or there is a population of binary neutron stars that we’re just now detecting in other galaxies,” he said. “There is so much that we don’t know.”
Conducting research like this takes a lot of time and a lot of data. According to Farr, there are two main sites in the United States where this kind of data can be collected. There are also sites located in Japan and Italy.
“The LIGO detectors are these big ‘L’ shaped buildings. We have one near us, in Washington, and we have another in Louisiana. Each arm of the building is 2.5 miles, and they are big long vacuum tubes,” said Farr. “In the middle of the ‘L’, we have a high-powered laser. The laser is sent down each arm of the ‘L’ and shoots all the way to the end and shoots off mirrors to return.”
After the lasers are shot out the ends, they return back to Earth – and if the paths of return are different in length, that’s when you can tell an event has occurred and the space-time has compressed, Farr explained. The other half of the process includes creating theory and building a cohesive idea behind what each event could mean and how they are significant to the bigger picture.
Farr has moved to a managerial position and teaching rather than engaging directly with research. His goal is to get the group working in a way that’s sustainable for the next few years, with a smoother and faster data collection process.
“In the future, we want to be able to put all of it together to make a clear picture of what the whole population of systems that we’re seeing look like,” he said. “I was really lucky to be born when I was so that my professional career trajectory could take me through the discoveries at just the right time that I get to keep doing this science.”
Farr is teaching data science geared towards physicists. He recommends that students delve into data-based physics classes for an introduction to this kind of work. Eventually, he said he’d like to get back into research on this topic.
“We’re moving from having one detection every several months to having more like one event per day. It’s growing really fast,” he said. “There hasn’t been a slow enough period to get bored. Gravitational astronomy is going to be around for a long time and is getting more exciting.”