CALLISTO (Syllabus: GS Paper 3 – Sci and Tech)

News-CRUX-10     2nd April 2024        
output themes

Context: An international team of scientists, including from India, has discovered strong evidence indicating the presence of ozone on Jupiter’s moon, Callisto, shedding light on the complex chemical processes taking place on icy celestial bodies in the Solar System.


  • Abundance of Moons: Jupiter possesses the most moons in the Solar System.
  • Callisto's Stature: Callisto, among Jupiter's largest moons, ranks third in size across the Solar System, following Ganymede and Titan.
  • Composition: Despite its substantial size comparable to Mercury, Callisto holds less than half the mass, primarily composed of water ice, rocky materials, sulphur dioxide, and organic compounds.
  • Potential for Life: Callisto's diverse composition raises the possibility of supporting life beyond Earth within the solar system.
  • Surface Characteristics: Callisto's surface exhibits heavy cratering, potentially indicating the oldest surface in the Solar System, with limited seismic activity compared to other Jupiter moons.
  • Geological Inactivity: Callisto's relatively few geological features suggest geological inactivity, implying surface stability crucial for preserving potential subsurface oceans or habitats.
  • Scientific Investigation: The detection of sulphur dioxide on Callisto's surface prompts further spectroscopic observations to unravel its surface composition and formation.

Ozone Layer

  • About: It is a natural gas, an allotrope of oxygen consisting of 3 atoms of oxygen bound together in non-linear fashion.
  • It is found in two different layers of the atmosphere: one in the troposphere (bad ozone leads to the formation of smog) and the other in the stratosphere (good ozone that protects from harmful UV radiations).
  • Protective shield: in the Earth's stratosphere.
  • Filters out: harmful ultraviolet (UV) radiation from the Sun.
  • Role: is vital in safeguarding human health and the environment.
  • Prevention: It helps prevent health conditions such as skin cancer, cataracts, and immune system suppression.