Good question! Venus is much like Earth in
some ways, but in other ways it is very
different. The size and density of Venus is very
similar to Earth, but its atmosphere is very
different. The atmosphere is the layer of gas
surrounding the surface of a planet, and it is
very important in the livability of a planet
because most life (on Earth) is at or very near
to the surface.
Venus’ atmosphere is mostly composed of
carbon dioxide. It is very dense (about 90 times
the pressure of Earth’s atmosphere) and very hot
(about 500 Centigrade) because of an
extreme “greenhouse effect” from the carbon
dioxide (Hamblin & Christiansen, 2004).
Obviously, it would be impossible for a human to
live there– we would be cooked by the heat and
crushed by the pressure, but what about other
Life on Earth can live in extreme
environments, like the freezing cold desserts of
Antarctica and the boiling hot pools in
Yellowstone. Organisms that live in these types
of environments are known as “extremophiles”.
Could an extremophile live on the surface of
Venus? Life (as scientists understand it)
requires at least two main things: 1) liquid
water for chemical reactions to happen in and 2)
a source of energy. Humans drink water
to “hydrate” our cells and get energy by eating
carbon and combining it with the oxygen that we
breathe, but there are other ways to get energy
as well. Some organisms get all of their energy
from “chemical reactions” that take place in
their environment. For example, the bacteria
that live in hot, acidic pools in Yellowstone
take advantage of the combination of sulfur and
oxygen in the pools. There may be the potential
for the first requirement on Venus. For example,
an organism with a similar “metabolic pathway”
as plants might be able to get their energy from
the carbon dioxide and sunlight on Venus
(although not much sunlight makes it through the
dense atmosphere). Liquid water is the
requirement that Venus probably does not fill.
Scientists think that there may have been liquid
water on Venus’ surface in the past, but not any
Reference: Hamblin, W.K. & Christiansen, E.H.
(2004). Earth’s Dynamic Systems. New Jersey:
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