At the IceCube Neutrino Observatory at the South Pole, an Israeli scientist and her team are unraveling universal questions.
![Breaking the Ice in Search of Cosmic Answers](/media/2492/breaking-the-ice-in-search-of-cosmic-answers.jpg)
Hagar Landsman-Peles and flags at the South Pole. Photo by Hagar Landsman-Peles
A year and a half ago, after almost a decade of construction, a unique particle detector known as the IceCube Neutrino Observatory was inaugurated at the South Pole.
Particle detectors are meant to smoke out the smallest units of high energy, and this observatory hosts thousands of small detectors, buried in 86 holes, 1.5 to 2.5 kilometers deep across a square kilometer of Antarctic tundra.
These detectors are supposed to solve science’s biggest questions. Their mission? Track down and identify the elusive, mass-less particles known as neutrinos, which come from cosmic rays, violent explosions of massive stars and other yet-to-be identified sources.
Neutrinos could hold the key to many of the questions plaguing modern cosmology, among them the mysterious identity of dark matter particles, which, hypothesis holds, constitute a quarter of all the mass and energy in the universe.
But neutrinos are sneaky little suckers, and they are anti-social to boot. Observing these particles, which don’t like to interact with each other and constantly slip in and out of the earth, is a significant challenge. Neutrinos know how to play the game: they are the originally purveyors of “hard to get.”
But the neutrino may have finally met its polar match. IceCube is massive, a glacial, uber-deep astronomical fishing net that at long last offers scientists with closer glimpse of these sly cosmic emissions.
Only a few dozen scientists on earth were on hand in Antarctica when the site was being constructed, and Dr. Hagar Landsman-Peles of the Weizmann Institute in Israel was one of them. She examined the particle detectors before burial, making her one of the last people to handle them before their plunge deep into the frozen ground of the South Pole.
The project cost $280 million, funded mostly the U.S. National Science Foundation and managed by the University of Wisconsin-Madison. There was no room for error.
“Once you put a detector in the ice, it’s there to stay, for good,” said Landsman-Peles. “We had to make sure they’re completely functional.”
When neutrinos at the IceCube facility collide with oxygen atoms in the ice, scientists know they are getting somewhere. These rare collisions create a new particle, emitting radiation that can only be detected in the utter darkness of the glacial depths.
“Neutrinos can go through the earth like a knife in butter, so we’re waiting for such collisions to happen in a massive section of ice,” Landsman-Peles explains.
But when you are cutting into the belly of the earth, nothing is quite so simple. “The ice needs to be transparent, because it is only 2 kilometers underground, and it also needs to be isolated from other forms of cosmic radiation that could jam the detection,” Landsman-Peles says.
Most telescopes can only detect photons, the elementary particles that together build light. IceCube’s capacity to identify neutrinos, then, pries open a new window to the universe.
“We believe neutrinos are deeply connected to most of the astrophysical phenomena we know of,” says Landsman-Peles. “They can travel vast distances without stopping, unlike photons, which can be blocked by almost anything. Neutrinos give us a deeper, high-energy perspective of the universe.”
Incomparably bright flashes
Landsman-Peles also says that IceCube will provide scientists with a broader picture of gamma ray bursts, the incomparably bright flashes of gamma rays that occur when stars explode. And, ever the over-achiever, the observatory will also give scientists a leg up both in identifying new particles and in providing evidence for the elusive dark matter.
“This is the Hubble of neutrino particles,” Landsman-Peles says of the observatory. “It will help answer the same questions that the space telescope deals with.”
Constructing and operating an observatory at the heart of the South Pole is no picnic. The scientists convene in the southern hemisphere’s summer, which lasts from November to mid-February and is a season in which the sun never sets.
But don’t fool yourself. It’s still cold in summer – very cold.
“We’re happy when it’s minus 30 degrees Celsius,” Landsman-Peles said. “That’s considered a good day.”
The inhuman temperatures aren’t the only challenges facing the staff, who sometimes spend hours outside of the base.
“We suffer there from altitude sickness. The scientific station is more than 3 kilometers above sea level, so oxygen levels are low. And the air is terribly dry, which is actually harder to deal with than the cold,” Landsman-Peles said.
Even getting to the base is a challenge. The trek to the spot, buried deep within the Antarctic tundra, takes five to six days. And in such an environment, the cost of even basic necessities is inflated, so staffers know they will be roughing it.
“Water is a rare resource here,” Landsman-Peles says, so workers know they can only grab a couple of two-minute showers a week.
Despite the conditions, Landsman-Peles is eager to get back to the base. This January, she will once again make the odyssey to the earth’s end to work on a new, related project, known as the Askaryan Radio Array. The ARA is a new particle detector that, when finished, will spread over 100 square meters with a depth of a few hundred meters below the ice. And despite the grueling days ahead of her, Landsman-Peles is excited.
“Antarctica is a special place. People say that when from the moment you step off the plane, you either immediately love the place or hate it. People’s feelings about this are very extreme and unpredictable,” she says. “The South Pole is nothing like what you see in the movies. There’s no life, no vegetation. It is a desert of white ice. But I love it there.”
The work of Landsman-Peles and her colleagues, however, is not for the faint-hearted.
“This is not the ordinary work of physicists, standing next to the chalkboard with messy hair and a white robe. It’s a scientific adventure.”