The detection of ozone on Jupiter’s moon Callisto is a landmark discovery that sheds light on the chemical processes at play on icy moons in our Solar System. This finding opens doors for further exploration and could lead to new insights into the possibility of life beyond Earth.
Discovery of Ozone on Callisto
Study Publication
- Published in the March 2024 issue of the journal Icarus.
- Outlined investigation into the chemical evolution of ‘SO2 astrochemical ice’.
Chemical Processes on Callisto
- Shed light on chemical processes and composition of Callisto’s surface.
- Ice primarily composed of sulphur dioxide (SO2) in the presence of ultraviolet irradiation.
Identification of Ozone Formation
- Analysis of UV absorption spectra of irradiated ice samples.
- Distinct signature indicating the formation of ozone.
Corroboration of Findings
- Comparison with data from the Hubble Space Telescope.
- Understanding Callisto’s environment and potential habitability of icy moons in the Solar System.
Importance of Ozone
Earth’s Resources for Life
- Sunlight with suitable radiation frequencies.
- Water and stable atmosphere.
- Various compounds for biochemical processes.
Harmful Effects of Ultraviolet Radiation
- Ultraviolet-B (290–320 nanometres) and Ultraviolet-C (100-280 nanometres) damage DNA.
- Increase risk of skin cancer and cataracts in humans.
- Inhibit plant growth and harm organisms.
Role of Ozone Layer
- Ozone molecule composed of three oxygen atoms.
- Located in the lower part of the earth’s stratosphere (15–35 km above ground).
- Absorbs ultraviolet-B and ultraviolet-C radiation.
Importance of Ozone Layer
- Shields Earth’s surface from harmful radiation.
- Without ozone layer, higher radiation levels would render the planet uninhabitable.
- Critical for maintaining ecosystems and supporting diverse species.
Exploration of Ozone in the Solar System
- Scientists studying celestial bodies showing signs of ozone.
- Indicates stable atmospheric conditions.
- Suggests potential for hosting life on these bodies.
Callisto’s Unique Environment
After Saturn, Jupiter has the most moons in the Solar System
Moon Characteristics
- One of Jupiter’s largest moons.
- Third-largest moon in the Solar System after Ganymede and Titan.
- Primarily composed of water ice, rocky materials, sulphur dioxide, and organic compounds.
Potential for Life
- Despite its size, Callisto has less than half the mass of Mercury.
- Composition makes it a potential candidate for supporting life beyond Earth.
Surface Features
- Heavily cratered surface.
- Indicates a long history of asteroid and comet impacts.
- Possibly the oldest surface in the Solar System.
Seismic Activity
- Lacks extensive seismic activity seen on other Jupiter moons like Io and Europa.
Geological Activity and Surface Composition of Callisto
Surface Stability
- Relatively few geological features suggest geological inactivity.
- Stable surface crucial for preserving potential subsurface ocean or habitats.
Spectroscopic Observations
- Detection of sulphur dioxide on Callisto’s surface prompted spectroscopic observations.
- Aimed to understand surface composition and formation.
Also Read | NASA’s Webb Telescope Finds Presence Of Carbon Source On Jupiter’s Moon Europa
Experiment to Recreate Conditions on Callisto
Research Led by R. Ramachandran
- Investigated chemical evolution of sulphur dioxide ice under irradiation.
- Aimed to simulate ozone formation on Callisto’s surface.
Laboratory Experiment
- Recreated conditions of sunlight hitting Callisto’s surface.
- Used vacuum ultraviolet photons to mimic solar radiation.
- Conducted experiments at National Synchrotron Radiation Research Centre in Taiwan.
Absorption Spectrum Analysis
- Lithium fluoride substrate placed in low-pressure chamber to mimic Callisto’s surface.
- Sulphur dioxide ice samples deposited onto the substrate.
- Temperature controlled throughout the experiment.
- Irradiated ice with vacuum-ultraviolet photons and observed absorption spectrum changes.
Discovery of Ozone and Implications for Habitability
Presence of Ozone
- Discovery suggests presence of oxygen, essential for life.
- Raises questions about Callisto’s habitability and potential for complex molecule formation.
Unidentified Band in Absorption Spectrum
- Similar to observation on Ganymede in 1996.
- Indicates common molecular source or chemical processes.
- Provides insights into geological and atmospheric processes on icy moons.
Source: Team led by PRL Ahmedabad finds ozone on Jupiter’s moon, The Hindu, April 2, 2024