The optical dust logger has dated the bottom of the IceCube array at between 90,000 and 100,000 years old. It’s that flash of light that IceCube captures using strings of digital optical modules frozen in the ice sheet. The subatomic traffic accident produces another particle called a muon, which leaves a trail of blue light in its wake. IceCube can help scientists trace the neutrinos back to their place of origin by capturing the incredibly brief interaction of the particles with other atoms as they speed through ice.
Physicists believe neutrinos carry unadulterated information about such intergalactic events thanks to their ability to zip through anything in the universe without changing course. The bottom graph shows how the comparison helps date the South Pole ice sheet.
Graphic Credit: Ryan Bay Plots compare the results of the optical dust logger at IceCube (top) with ice-core records at Dome C and Dronning Maud Land (middle). These high-energy particles are produced from violent events in the distant corners of the universe, such as exploding stars or by the formation of black holes. Ī “telescope” buried within a cubic kilometer of ice between 1,450 and 2,450 meters near the geographic South Pole, IceCube seeks to track down cosmic neutrinos. Most recently, they’ve sent it down six of the 59 holes drilled so far at the South Pole for the IceCube Neutrino Observatory. “There’s a lot of tantalizing information in those particulates,” he said.īay and colleagues have used the optical dust logger since 2000, analyzing dust concentration as a proxy for climate change, as well as a way to date and correlate different ice cores in Antarctica and Greenland. Bay said this abrupt cooling event could then affect the succeeding climate for millennia. The sulfate aerosols reflect sunlight, effectively shielding the lower atmosphere of the planet and cooling it near the surface. “Some of the best examples of abrupt climate change occurred on the millennial time scale in which you had temperature changes of 10 or 20 degrees within a few decades.”įor instance, a major volcanic eruption can send a great amount of sulfate particles into the atmosphere. “One of the things we’re interested in is what caused these climate changes,” Bay said. Bay said he is particularly interested in the last 100,000 years of climate history and finding signatures of volcanic eruptions and impacts from comets or asteroids that may have caused abrupt climate changes. The 3,270-meter-long ice core drilled by the European Project for Ice Coring in Antarctica (EPICA) reaches back at least 800,000 years. They’ll send the instrument down the deepest hole ever drilled in the ice sheet, where European scientists recovered the oldest ice to date from a high-altitude spot on the polar plateau called Dome C in East Antarctica. We can tell other people where to look in the core for interesting things, particularly very brief fallout layers like volcanic ash.”īay and team member Delia Tosi will take the latest and greatest version of their optical dust logger to Antarctica this coming field season. “We can see things that other people can’t see in the core. We’re trying to look outside the borehole into the surrounding ice,” Bay explained. We don’t measure the borehole itself or the wall. Ryan Bay has sent an optical dust logger down some of the boreholes.
At bottom is the IceCube drill camp, which is building a neutrino detector under the ice. Photo Credit: Henry Malmgren/Antarctic Photo Library The Dark Sector at the South Pole where many of the astrophysical experiments are located.