Antarctic Impulsive Transient Antenna: ANITA | 27 May 2020

Why in News

Recently, NASA’s Antarctic Impulsive Transient Antenna (ANITA) has detected the unusual upward movement of neutrinos in Antarctica.

  • Instead of the high-energy neutrinos streaming in from space, they seem to have come from the Earth's interior, before hitting the detectors of ANITA.
    • Usually, the high-energy particles move top to bottom (i.e. from space to the earth). However, ANITA has detected an anomaly i.e. particles have been detected travelling bottom to top.
  • Earlier, researchers had also located a deep-space source for high-energy neutrinos through the Ice Cube Neutrino Observatory at a U.S. scientific research station at the South Pole in Antarctica.
    • The India-based Neutrino Observatory (INO) is located at the Bodi West Hills region in Theni District of Tamil Nadu.

Antarctic Impulsive Transient Antenna

  • Antarctic Impulsive Transient Antenna (ANITA) is a radio telescope instrument to detect ultra-high energy cosmic-ray neutrinos from a scientific balloon flying over the continent of Antarctica.
    • It involves an array of radio antennas attached to a helium balloon which flies over the Antarctic ice sheet at 37,000 meters.
    • At such a height, the antennas can listen to the cosmos and detect high-energy particles, known as neutrinos, which constantly bombard the planet.
  • It is the first NASA observatory for neutrinos of any kind.
  • ANITA detects neutrinos pinging in from space and colliding with matter in the Antarctic ice sheet through the Askaryan effect.
    • The Askaryan effect is the phenomenon whereby a particle traveling faster than the phase velocity of light in a dense dielectric (such as salt, ice or the lunar regolith) produces a shower of secondary charged particles.
      • When neutrinos smash into an atom, they produce a shower of detectable secondary particles.These detectable secondary particles allow us to probe where they came from in the universe.
      • However, neutrinos pose no threat to human beings and pass through most solid objects. Additionally, they rarely do interact with matter.
    • It is named after Gurgen Askaryan, a Soviet-Armenian physicist who postulated it in 1962.


  • Neutrinos are electrically neutral, undisturbed by even the strongest magnetic field, and rarely interact with matter. The direction from which they arrive points directly back to their original source.
  • Neutrinos are produced during natural radioactive decays and all sorts of nuclear reactions in nuclear power reactors, particle accelerators or nuclear bombs.
  • However, the most common sources of neutrinos are celestial phenomena i.e. the birth and death of stars, collisions, and explosions happening in space.

Way Forward

  • The ANITA experiment has definitely detected something unusual and unexpected about neutrinos but there are many competing theories about it. There are a number of potential candidate particles that could account for the results from ANITA.
  • Further, there are so many unknown properties about neutrinos that astrophysicists and scientists are still trying to unravel.
  • It contemplates that there is new physics out there to be found which will help to study the origin of the universe and big bang theory in the future.