ISRO Missions and Discoveries

Ozone found on Jupiter’s moon Callisto


From UPSC perspective, the following things are important :

Prelims level: Ozone, Jupiter's Compositions, Its moon

Mains level: NA

Why in the news?

PRL Ahmedabad researchers has uncovered evidence of ozone presence on Jupiter’s moon Callisto, offering profound insights into celestial chemical processes.

About Jupiter and its Moons

Discovery Known since ancient times;

Galileo Galilei observed Jupiter and its moons through a telescope in 1610

Composition Mostly composed of hydrogen and helium, with traces of other gases such as ammonia, methane, and water vapor
Diameter 139,822 kilometers
Mass 1.898 × 10^27 kilograms (317.8 Earth masses)
Orbital Period Approximately 11.86 Earth years
Average Distance from Sun Approximately 778 million kilometers
Surface Temperature Approximately -145°C (-234°F)
Magnetic Field Strong magnetic field, the strongest in the solar system
Moons Jupiter has 79 known moons, including the four largest Galilean moons: Io, Europa, Ganymede, and Callisto.

Other notable moons include Amalthea, Himalia, Elara, Leda, Thebe, Metis, Adrastea, and more.

The moons vary significantly in size, composition, and orbital characteristics.

Great Red Spot Enormous storm system, known to exist for at least 400 years
Exploration Explored by spacecraft such as Pioneer, Voyager, Galileo, Juno, and more

Callisto and its Unique Environment

  • Composition: Callisto’s predominantly icy surface, interspersed with rocky materials, sulphur dioxide, and organic compounds, positions it as a compelling candidate for extraterrestrial life exploration.
  • Geological Stability: Despite extensive cratering, Callisto’s surface exhibits geological inactivity, suggesting long-term stability conducive to preserving subsurface oceans or potential habitats.

Significance of Ozone Findings

  • Life-Sustaining Component: Ozone, a molecule composed of three oxygen atoms, plays a vital role in shielding celestial bodies from harmful ultraviolet radiation, fostering conditions conducive to life.
  • Earthly Parallel: Just as the Earth’s ozone layer protects against harmful UV radiation, the presence of ozone on Callisto hints at stable atmospheric conditions and potential habitability, sparking scientific intrigue.


What is the difference between asteroids and comets?

1.    Asteroids are small rocky planetoids, while comets are made of ice, dust and rocky material.

2.    Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury.

3.    Comets show a perceptible glowing tail, while asteroids do not.

Which of the statements given above is/ are correct? (2011)

(a) 1 and 2 only

(b) 1 and 3 only

(c) 3 only

(d) 1, 2 and 3

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