Neutrino Observatory (SNO), a 2100m underground observatory in Sudbury, Canada, is the other site where neutrino oscillation research was taking place in the late 1990s, early 2000s. The results from experiments at this observatory along with those at Super-Kamiokande are what helped solve the solar neutrino problem. The SNO is also a heavy-water Cherenkov detector and designed to work the same way as the Super-Kamiokande. The Neutrinos when reacted with heavy water produce the blue Cherenkov light, signaling the detection of neutrinos to researchers and observers. Borexino The Borexino detector is located at the Laboratori Nazionali de Gran Sasso, Italy. Borexino is an actively used detector, and experiments are on-going at the site. The goal of the Borexino experiment is measuring low energy, typically below 1 MeV, solar neutrinos in real-time. The detector is a complex structure consisting of photomultipliers, electrons, and calibration systems making it equipped to take proper measurements of the low energy solar neutrinos. Photomultipliers are used as the detection device in this system as they are able to detect light for extremely weak signals. Solar Neutrinos are able to provide direct insight into the core of the Sun because that is where the solar neutrinos originate. Solar Neutrinos leaving the Sun's core reach Earth before light does due to the fact solar neutrinos do not interact with any other particle or subatomic particle during their path, while light (photons) bounces around from particle to particle. The Borexino experiment used this phenomenon to discover that the Sun releases the same amount of energy currently as it did a 100,000 years ago. IceCube Neutrino Observatory The IceCube Neutrino Observatory is located in Antarctica at the Amundsen-Scott South Pole Station. The observatory consists of photomultiplier tubes and thousand of spherical sensors located under the ice spread out over an area of greater than one cubic kilometer. Physicists conduct research at the Antarctic observatory aimed to answer questions concerning not just neutrinos and solar neutrinos but also cosmic rays and dark matter. Formation process Solar neutrinos are produced in the core of the Sun through various nuclear fusion reactions, each of which occurs at a particular rate and leads to its own spectrum of neutrino energies. Details of the more prominent of these reactions are described below. The main contribution comes from the proton–proton chain. The reaction is: or in words: two protons deuteron + positron + electron neutrino. Of