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What are the conditions for Habitability? These factors together contribute to determining
1. Solvent: A suitable liquid solvent, like water, is whether a planet can support life. While certain
necessary for essential reactions and support of life. conditions are vital, the interplay of all these
Planets with significant liquid water are categorised factors is complex, and no single factor
as surface liquid water worlds or interior fluid guarantees habitability.
water worlds.
Where does Phosphorus come in?
2. Physicochemical Conditions: Temperature,
radiation, pressure, pH, salinity, aridity, and toxic Of all the significant elements required for
metal levels need to be within limits for organisms life- Carbon, Hydrogen, Nitrogen, Oxygen,
to survive. Some microorganisms can withstand Phosphorus & Sulphur (CHNOPS), Phosphorus
extreme conditions. is the most unique.
3. Available Energy: Organisms require energy to Termed the "Staff of Life", Phosphorus is present
carry out life processes, and the environment must in the "blueprint" of all forms of life- the DNA-
provide sufficient energy sources (e.g., light) for and forms the base of ADP and ATP, necessary
this purpose. for providing energy to all organisms, which is
used during their metabolic processes. It is an
4. Major Elements (CHNOPS): Carbon, Hydrogen, indisposable element which played a significant
Nitrogen, Oxygen, Phosphorus, and Sulphur are role in the origin of life itself. Furthermore,
essential elements for life, each serving unique Phosphorus is essential for terrestrial biological
functions. Their presence in various forms is productivity and is critical to carbon balance in
crucial for supporting life. terrestrial ecosystems.
5. Specific Elements: Some organisms require It is present in the form of various compounds
specific elements like iron, manganese, and in the environment, which may be in the soil,
potassium. Life itself can alter element availability dissolved in water or even as a gas in the
in a habitat over time. atmosphere.
6. Atmosphere and Planetary Factors: Mass, density, Despite its ability to aggregate into various
atmosphere composition, plate tectonics, and compounds (PO43-, Ca5(PO4)3OH, PH3, etc.),
magnetic field influence a planet's suitability for Phosphorus is the limiting nutrient out of all the
life. While they help categorise habitability, they significant nutrients. This can be explained by
are not sole determinants. looking at the phosphorus cycle. Simply put,
fresh Phosphorus available for life is released
7. Astronomical Factors: Planetary rotation, orbital majorly only during soil weathering. Transporting
characteristics, star type, and impact events impact this weather phosphorus by the rivers and other
a planet's conditions, including temperature, water bodies is the only appreciable source of
element composition, and overall habitability. Phosphorus in the oceans.
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