Searching for a cosmic needle in a galactic haystack
For a time in early January 2017, Dr. Victoria Kaspi and a team of fellow researchers were media darlings. Her work on radio waves from a galaxy estimated to date back as many as three billion years was originally published in the journal Nature and that’s when media outlets like the New York Times — front page, no less — Scientific American and CNN started requesting interviews.
The radio waves, known as fast radio bursts, are newly discovered astrophysical phenomena in the sky. Unfortunately (at least for those hoping humans will one day prove there is alien life elsewhere) the paper’s 25 researchers think the waves can be explained with good old run-of-the-mill astrophysics.
“We suddenly have this capability to detect brief pulses — they only last a few thousandths of a second — of radio waves that are coming from all over the sky,” says Kaspi. “They’re happening every day, but you can’t predict in which direction they’re going to happen. We don’t know what they are, but they’re not alien signals. It’s one of these mysteries. We’re trying to figure out a good way to answer the question.”
Kaspi loves a good puzzle and that’s why her team is so dedicated to this latest research. To that end, they’re part of a team building a highly sophisticated radio telescope in Canada.
“It’s called the CHIME [Canadian Hydrogen Intensity Mapping Experiment] telescope and it’s being built in Penticton, British Columbia,” she says. It’s funded by the Canada Foundation for Innovation.
The telescope was designed for cosmological observations and to understand mysterious dark energy, another puzzle in astrophysics, but it turns out the same design is also well suited to solving Kaspi’s fast radio burst puzzle.
The telescope involves on-site high-performance computing with totally dedicated processors and pipelines that do nothing but search data for fast radio bursts in real time. “They can identify them in real time and send an alert out to say one just happened, so other people can look into the sky in that area and see if there’s other activity there,” says Kaspi.
Her other line of research involves neutron stars, which are close cousins of black holes, but aren’t collapsed to a point like a black hole is, making them easier to observe.
“What makes them so exciting is that we can study extreme physics, specifically the physics of how materials behave in the highest magnetic fields known in the universe, with telescopes,” she says.
Neutron stars give her team access to those extreme conditions, none of which can be simulated in terrestrial laboratories.
“It’s like a cosmic physics laboratory that we can’t reproduce here on earth,” she says.
Kaspi has used pulsars — a type of neutron star that pulsates regularly and act as a kind of cosmic lighthouse — to test Einstein’s theory of relativity, which, she’s happy to report, works well, even in situations where Newton’s laws break down.
“We can measure how fast the pulsar’s going and that allows us to test what different models for extreme gravity would predict,” she says. “Newton’s laws
break down when things start to move at close to the speed of light. You find some of these binary pulsars orbiting at appreciable fractions of the speed of light so their orbits are only a few hours. When Newton’s laws break down, you need Einstein’s theory.”
Her research requires high-powered computing to understand what’s happening with these stars.
“You need to visualize and manage big data so you end up pushing the frontier of computer science, algorithms and big data management to answer a very simple physical question that today may not have any practical application,” she says. “But let’s say we did figure out what’s inside a neutron star and the physics of material at ultra-high densities. Who knows what that knowledge would lead to? If we suddenly understand the behaviour of matter, we could maybe design a pellet the size of your pinky that could power your car for a millennium.”
Kaspi uses Compute Canada’s resources for all her work.
“With fast radio bursts, you’re looking for really short events. So you sample data every 64 microseconds, so you get voluminous amounts — it’s like looking for a needle in a haystack,” she says. “We use Compute Canada’s resources to do those searches quite successfully. It is fair to say I need their resources to do my job.”
For her work over the past 25 years, Kaspi has been named to the Order of Canada. It was a man she doesn’t know — Michael Steinitz, professor emeritus at St. Francis Xavier University — who nominated her.
“It’s was a big surprise and it’s a huge honour,” she says. “I’m very grateful for it.” The award might inspire more women to join her in her field. “I am one of few women in my field,” she says. “However, there are significant cultural biases that hinder women from going into the hard sciences. My advice to young women is to be aware of that and do your best not to let it influence you. If you enjoy science and want to do it, go for it.”