THE ATMOSPHERE AND
RESPIRATION
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We breathe every moment of our lives. We
continuously take the air into our lungs and let
it out. We do it so much that we might think of
it as normal. In fact, respiration is quite a complex
process. Our
bodily systems are so perfectly designed that
we don't need to think about breathing. Our body
estimates how much oxygen it needs and arranges
for the delivery of the right amount whether we're
walking, running, reading a book, or sleeping.
The reason breathing is so important to us is
that the millions of reactions that must constantly
take place in our bodies to keep us alive all
require oxygen.
Your ability
to read this book is thanks to the millions of
cells in the retina of your eye constantly being
supplied with oxygen-derived energy. Similarly,
all the tissues of our bodies and the cells forming
them get their energy from the "burning" of carbon
compounds in oxygen. The product of this burning–carbon
dioxide–must be discharged from the body. If the
level of oxygen in your bloodstream drops to low,
the result is fainting; and if the absence of
oxygen persists for more than a few minutes, the
result is death.
And that's why
we breathe. When we inhale, oxygen floods into
about 300 million tiny chambers in our lungs.
Capillary veins attached to these chambers absorb
the oxygen in a twinkling and convey it first
to heart and then to every other part of our body.
The cells of our body use this oxygen and release
carbon dioxide into the blood, which conveys it
back to the lungs where it is expelled. The whole
thing takes less than half a second: "clean" oxygen
comes in and "dirty" carbon dioxide goes out.
You might be
wondering why there are so many (300 million)
of those little chambers in the lungs. They're
there to maximize the surface area that is exposed
to the air. They're carefully folded up to occupy
as little space as possible; if they were unfolded,
the result would be enough to cover a tennis court.
There is another
point here that we need to keep in mind. The chambers
of the lungs and the capillaries connecting to
them are designed so small and perfectly in order
to increase the rate at which oxygen and carbon
dioxide are exchanged. But that perfect design
depends on other factors: the density, viscosity,
and pressure of air must all be right in order
for the air to move properly in and out of our
lungs.
At sea level,
air pressure is 760 mm of mercury and its density
is about 1 gram/liter. Again at sea level, its
viscosity is nearly 50 times that of water. You
might think these numbers unimportant but they
are vital for our lives because, as Michael Denton
notes:
The overall
composition and general character of the atmosphere–its
density, viscosity, and pressure, etc-–must
be very similar to what it is, particularly
for air-breathing organisms.1
When we breathe,
our lungs use energy to overcome a force called
"airway resistance". This force is the result
of the resistance of air to movement. Owing to
the physical properties of the atmosphere however,
this resistance is weak enough that our lungs
can take air in and let it out with a minimum
expenditure of energy. If air resistance were
higher, our lungs would be forced to work harder
to enable us to breathe. This can be explained
by an example. It easy to draw water into the
needle of an injector but drawing honey in is
much more difficult. The reason is that honey
is denser than water and also more viscous.
 If
the density, viscosity, and pressure of air were
higher, breathing would be as difficult as drawing
honey into a needle. Someone might say "That's
easy to fix. We'll just make the hole of the needle
larger to increase the rate of flow." But if we
did that in the case of the capillaries in the
lungs, the result would be to reduce the size
of the area in contact with air, with the result
that less oxygen and carbon dioxide would be exchanged
in the same amount of time and the respiratory
needs of the body would not be satisfied. In other
words, the individual values of air's density,
viscosity and pressure must all fall within certain
limits in order for it to be breathable and those
of the air we breathe do exactly that.
Michael Denton
comments on this:
It is clear
that if either the viscosity or the density
of air were much greater, the airway
resistance would be prohibitive and no
conceivable redesign of the respiratory system
would be capable of delivering sufficient oxygen
to a metabolically active air-breathing organism...
By plotting all possible atmospheric
pressures against all possible oxygen contents,
it becomes clear that there is only one unique
tiny area... where all the various conditions
for life are satisfied... It is surely
of enormous significance that several essential
conditions are satisfied in this one tiny region
in the space of all possible atmospheres.2
The numerical values of
the atmosphere are not only necessary for us to
breathe but are also essential for our Blue Planet
to stay blue. If sea-level atmospheric pressure
were much lower than its present value, the rate
of water vaporization would be much higher. Increased
water in the atmosphere would have a "greenhouse
effect" trapping more heat and raising the average
temperature of the planet. On the other hand,
if the pressure were much higher, the rate of
water vaporization would be less, turning large
parts of the planet into desert.
All these finely-tuned
equilibriums indicate that our atmosphere has
been deliberately designed precisely so that life
on Earth can exist. This is the reality discovered
by science and it shows us again that the universe
is not just an accidental jumble of matter. Undoubtedly
there is a Creator ruling the universe, shaping
matter as He wants it to be, and reigning over
the galaxies, stars and planets under His sovereignty.
That supreme
power, as the Qur'an tells us, is Allah, Lord
of the whole universe.
And the Blue
Planet on which we live is specially designed
and “smoothed out” by Allah for people
as stated in the Qur'an. (Surat an-Naziat
30) There are other verses revealing that Allah
has created Earth for mankind to live in:
It
is Allah who made the earth a stable home for
you and the sky a dome, and formed you, giving
you the best of forms, and provided you with
good and wholesome things. That is Allah,
your Lord. Blessed be Allah, the Lord of all
the worlds. (Surah Ghafir: 64)
It
is He Who made the earth submissive to you,
so walk its broad trails and eat what it provides.
The Resurrection is to Him. (Surat al-Mulk:
15)
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