Why in news?

• China is building an enormous telescope in the western Pacific Ocean. Its job will be to detect “ghost particles”, also known as neutrinos.
• China says its new telescope, called Trident, will span 7.5 cubic km in the South China Sea.
  • As per experts, its size will allow it to detect more neutrinos and make it 10,000 times more sensitive than existing underwater telescopes.

What’s in today’s article?

• Neutrino
• India-based Neutrino Observatory mission

What is Neutrino?

• Background
  • For a long time, scientists thought atoms were the smallest particle in existence.
  • This was before discovering that atoms are themselves comprised of even tinier “subatomic” particles:
    • protons (which have a positive charge), electrons (negative charge) and neutrons (no charge).
• About
• A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass, which might even be zero.
  • Neutrinos were long believed to be massless, until scientists found evidence that they do have a very small mass.
• Neutrinos are one of the most abundant particles in the universe.
• Nuclear forces treat electrons and neutrinos identically.
  • Neither participate in the strong nuclear force, but both participate equally in the weak nuclear force.
• Every time atomic nuclei come together (like in the sun) or break apart (like in a nuclear reactor), they produce neutrinos.
• Neutrino- a ghost particle
  • Neutrinos’ weak charge and almost non-existent mass have made them notoriously difficult for scientists to observe.
  • They can only be seen when they interact with other particles.
  • The rarity of interactions with other particles makes them almost impossible to track.
  • That is why they are called ghost particles — the vast majority skirt around undetected.

How do scientists detect ghost particles?

• Ghost particles rarely interact with other particles. But rarely doesnot mean never.
• Sometimes they interact with water molecules, which is why China is building its ghost molecule telescope underwater.
  • Scientists have observed ghost particles in fleeting instances when the particles create byproducts after traveling through water or ice.
• Right now, the largest neutrino-detecting telescope is the University of Madison-Wisconson’s “IceCube” telescope.
  • Situated deep in the Antarctic, the telescope’s sensors span around 1 cubic kilometer.

Why does the detection of ghost particles matter?

• Scientists donot really know why the massively abundant neutrinos act the way they do. They defy established rules of physics.
• It is not clear where the particles come from. Scientists think they might have played a role in the early universe, right after the big bang.
• A sound understanding of neutrinos will help solve a number of scientific mysteries — like the origin of the mysterious cosmic rays, which are known to contain neutrinos.
• There is evidence that neutrinos are essential for understanding the origins of our universe.

India-based Neutrino Observatory mission

• About
  • 
  • The Indian Neutrino Observatory (INO), approved in 2015, is a proposed particle physics research mega project.
  • Objective: To study neutrinos in a 1,200-metre-deep cave.
    • Neutrino detectors are often built underground to isolate them from cosmic rays from space and any other sources of background radiation.
• Goals
• The first phase would be to study the so-called atmospheric neutrinos produced by interactions of cosmic rays in the Earth's atmosphere.
  • Both neutrinos & antineutrinos of different species (flavours) are produced here.
• Many long-term options are associated with the project. For instance, researchers can use INO Project for solar and supernova studies in the future.
• Institutions involved
  • The INO is proposed to be operated by seven primary and 13 participatory research institutes, spearheaded by:
    • Tata Institute of Fundamental Research (TIFR) and
    • Indian Institute of Mathematical Sciences (IIMSc).
  • Project is jointly funded by the Department of Atomic Energy (DAE) and the Department of Science and Technology (DST).
• Location
  • In order to avoid the difficulty of identifying and separating signals produced by the neutrinos from those produced by other particles, the detector will be kept inside a mountain.
  • The neutrinos will easily pass through the mountain, and reach the detector, while other particles will be filtered out by the mountain rock.