Physicist Francis Halzen has been awarded the Nobel Prize in Physics for his work on an observatory that detects particles from space, according to BBC News. Born in Belgium and now a United States citizen at the University of Wisconsin in Madison, Halzen led the development of the IceCube Neutrino Observatory at the South Pole, a facility that places light sensors inside a cubic kilometre of Antarctic ice to catch particles known as neutrinos. These particles carry information about violent, high energy processes taking place across the cosmos, which makes them valuable to researchers studying the distant universe. The Royal Swedish Academy of Sciences said his vision and scientific leadership were fundamental to the observatory. Halzen first presented his idea for detecting neutrinos at the South Pole in 1988, and he told a news conference that he was surprised by how well it worked. He described himself as lucky, since many people thought the plan was a good one yet very few believed it would succeed, himself included.
Neutrinos are elusive subatomic particles, and the Sun produces them in vast numbers, with billions passing harmlessly through an area the size of a fingernail every second. IceCube, however, searches for neutrinos with far greater energy, the kind created by violent events well beyond the Solar System, in distant galaxies. The observatory is made up of thousands of sensors attached to long cables, which were drilled and frozen into a block of ice measuring one kilometre on each side. Most neutrinos pass straight through the ice, but on rare occasions one strikes an atomic nucleus and produces fast moving charged particles. Those particles race through the ice and give off a blue glow that sensitive light detectors can pick up. The pattern and timing of that light allow scientists to estimate the direction from which the neutrino arrived, and since such interactions are so uncommon, the project needed an enormous volume of clear ice, which led Halzen to propose the vast natural ice sheet in Antarctica.
The ghostly nature of the neutrino, the very quality that makes it so difficult to detect, also makes it a powerful messenger from far away. Since neutrinos seldom interact with matter, they can travel through dense regions that light cannot easily penetrate, and since they carry no electric charge, magnetic fields do not bend their paths on the way to Earth. Their direction of arrival can therefore point researchers back towards the source, and the particles reach Earth with their original information largely intact. The energies they carry also offer insight into how exploding stars and the environments around giant black holes accelerate particles to extraordinary levels. Prof Mark Pearce, Chair of the Nobel Committee for Physics, said Halzen led an international team of researchers and engineers who produced a fantastic instrument, adding that his tenacity and scientific vision paved the way for a new kind of astronomy, and that the work has given scientists a fresh method for studying the universe.
Reaction from the scientific community has been warm. Louis Barson, director of science at the Institute of Physics in London, said IceCube has allowed astronomers to investigate phenomena that conventional telescopes cannot see, and that the discoveries which followed are improving understanding of some of the most energetic and mysterious processes in the universe, thanks to the work of Halzen. Prof Subir Sarkar, a physicist at the University of Oxford, turned to the French novelist Marcel Proust to describe the contribution, recalling the idea that the only true voyage of discovery would be to possess other eyes and behold the universe through the eyes of others. In his view, Halzen guided the IceCube collaboration on exactly that kind of journey and opened a new window onto the universe. The prize also brings recognition to the many collaborators who built and operate the instrument beneath the ice, and the remarks reflect the wider appreciation of the project among physicists around the world.
Follow the SPIN IDG WhatsApp Channel for updates across the Smart Pakistan Insights Network covering all of Pakistan’s technology ecosystem.
