Over the weekend, Russian scientists lowered a series of detectors between 2,500 and 4,300 feet below the surface of Lake Baikal (via Phys.org). Together, these sensors form the Baikal-Gigaton volume detector, the largest underwater space telescope in the northern hemisphere. This will help scientists study neutrinos. Although one of the most abundant particles in the universe, neutrinos are also the smallest currently known to humans. They can also travel great distances without interacting with any other form of matter. These factors make them difficult to detect and study, but they can tell us a lot about the universe history.
A joint project between Russia, Germany, Poland, Slovakia and the Czech Republic, construction on Baikal-GVD began in 2015. The current “telescope” consists of hundreds of spherical glass and steel modules stainless steel connected to the surface by a set of cables. These sensors currently occupy an area of 17,657 cubic feet. Over time, the plan is to add more sensors to make the telescope even bigger.
As to why they would put these modules underwater, it’s a useful way to detect neutrinos and Lake Baikal has plenty of them. Located in southern Siberia, it is one of the largest and deepest freshwater lakes in the world. It is also pristine and covered in ice for at least two months a year. There aren’t many places on the planet as ideal for this type of research as Lake Baikal. The only other two telescopes that match the scale are the IceCube Neutrino Observatory in Antarctica and ANTARES telescope deep underwater in the Mediterranean Sea.