Prof. Peter Wittich, physics, received recognition recently for his contributions to Prof. Arthur McDonald’s project team, which resulted in the discovery of neutrino oscillations and earned a Nobel prize in physics.
The prize, awarded to McDonald of Queens University and Takaaki Kajita of University of Tokyo, recognizes the discovery of neutrino oscillation, a process that shows neutrinos have mass. Neutrinos were previously considered to be massless, and consequently this new research helps to explore how the sun works. The findings also verify Cornell physicist Hans Bethe’s explanation of the workings of the sun.
Wittich said he worked at the Sudbury Neutrino Observatory, the research lab over a mile underground in a nickel mine in Northern Ontario, while he was in graduate school. There, he measured the first one hundred days of data gathered on neutrinos.
Wittich said that the sun emits neutrinos, tiny particles, as a result of nuclear fusion that takes place at the sun’s core, according to The Ithaca Journal.
“There are trillions of them going through our bodies right now and we don’t notice them and it doesn’t do anything to us,” Wittich said.
These neutrinos, according to Wittich, have the ability to pass through nearly every material.
“Most particles when they hit a table, or a wall, they will stop,” Wittich said. “Neutrinos can go through light years of lead without interacting at all.”
This ability of the neutrinos to permeate different substances offered the researches an opportunity to study the core of the sun. According to Wittich, the visible light from the sun that reaches Earth mostly comes from the outer portion of the sun, after spending nearly ten thousand years within the sun itself.
“In that process you have lost a lot of information about that initial nuclear fusion reaction,” Wittich said. “If you look at the sun, effectively what you are looking at is what’s happening on the outer one percent of the sun.”
However, according to Wittich, neutrinos are able to penetrate through these layers of the sun, and so they carry information about what takes places at the very core of the sun.
“They basically move at the speed of light and come to us, and they are here in eight minutes,” Wittich said.
Still, he said the researchers found it challenging to observe neutrinos because their ability to pass through almost everything meant that they passed though most measuring devices.
“The same thing that means they get out of the sun is they’re extremely hard to capture, because they just go through everything,” Wittich said. “They don’t even see your apparatus that you put in their way.”
Wittich said the researchers devised a way to measure neutrinos by creating an enormous glass sphere and filling it with water. Surrounding this sphere, they placed thousands of devices to observe tiny flashes of light. The neutrinos would make this flash when they interacted with a water molecule.
“About 10 times a day they interact with a thousand tons of water. You will see 10 neutrinos a day,” Wittich said. “So of those trillions going through your body every second, imagine something that 1,000 tons of water, imagine how many are going through them and you only still detect 10 a day.”
The data gathered by the researchers proved that neutrinos change their form after leaving the sun — called neutrino oscillation — which in turn explained a previous gap in the amount of observed neutrinos, according to Wittich.
Wittich expressed the difficulty of conducting these observations nearly a mile underground in an active mine. In particular, he said, the lab had to be kept clean to prevent dust from giving false readings of neutrinos.
“The lab had to be kept cleaner than an operating room,” Wittich said. “Imagine you have something cleaner than an operating room that you are keeping in a super dusty, active mine environment.”
Wittich also said that he found working in the mine to be a unique and bizarre experience
“If they hadn’t air conditioned the mine, it would be about 40° Celsius, so well over 100° Fahrenheit,” Wittich said. “It’s such an otherworldly experience.”