The Troposphere is why we are alive. It keeps us warm and without
it we would have an average temperature of minus fifty degrees Celsius. The
atmosphere is equivalent to four point five metres thickness of concrete.
Without it invisible visitors from space would destroys us and raindrops would
beat us silly. The atmosphere extends up to one hundred and ninety kilometres
and is divided into four different layers. The Troposphere, Stratosphere, Mesosphere
and the Ionosphere which is now more commonly known as the Thermosphere. The
Troposphere alone has enough warmth and oxygen to keep us alive. It’s thickest
at the equator.
Beyond the Troposphere is the Stratosphere where an invisible
boundary lies in between them and flattens storm clouds into anvil shapes. It
is called the Tropopause which was discovered in 1902 by a Frenchmen called
Leon-Philippe Teisserene de Boit. The temperature there at 10km is minus fifty
seven degrees Celsius. After you leave the Troposphere the temperature warms
back up to four degrees Celsius because of the absorptive effects of the ozone
then it plunges to a minus ninety degrees Celsius in the Mesosphere before it
sky rockets to one thousand five hundred degrees Celsius where in the
Thermosphere the temperature can vary over five hundred degrees from day to
night.
Temperature is the measurement of active molecules. At sea level
air, molecules can only move a tiny distance before they bang into each other
due to how thick they are. Molecules are always colliding into each other and
when they hit one another heat gets exchanged except at fifty kilometres on the
top of the Thermosphere where molecules will barely come in contact with each
other which is good for spaceships, satellites because if there was more heat
any manmade objects would burst into flames.
Spaceships must take extreme care in the outer atmosphere. If a
spacecraft comes in at a steep angle for example 6 degrees it can generate drag
of an exceedingly combustible nature. Also it could simply rebound back into
space.
In the 1780’s people began to experiment with balloon ascents in
Europe and were surprised at how chilly it got above the ground. For each one
thousand metres the temperature dropped one point six degrees Celsius. They
thought the closer you got to a source of heat the hotter it became. The only
problem with that is the sun in ninety three million miles away and if it came
another hundred metres closer it would cause bushfires in Australia and the
smell of smoke in Ohio. Sunlight energises atoms which increases their activity
which leads to them banging into each other and releasing heat into the
atmosphere. Whenever you feel the warmth from the sunlight its really excited
atoms you are feeling.
Altogether there is about five thousand two hundred million tonnes
of air around us. Seven hundred and fifty million tonnes of cold air is pinned
under billions of tonnes of warm air. The air above our heads is also a source
of energy. One thunder storm has enough power to generate four days’ worth of
electricity in U.S.A. The sky is a very lively place. Every second about one
hundred lightning bolts hits the surface of the Earth accompanied by about
forty thousand thunderstorms per day. Air moves due to the internal engine of
the planet namely convection. Warm air rises from the equational area until it
hits the Tropopause then it spreads out across the sky cooling down overtime
until it sinks looking for an area with low pressure and then it heads back to
the equator where it finishes its cycle.
Low pressure areas are made from rising air which follows water
molecules into the sky forming clouds and rain. Tropical and summer storms are
heavier than other storms because warm air can hold more moisture than cool
air. Therefore areas with cloud and rain have a low pressured area and areas
with sunshine and a fair weather and a higher air pressure. Air pressures are
different due to the uneven heat from the sun. Air can’t avoid this so it
travels around trying to keep the air pressure even everywhere.
In Ecole Polytechmique in Paris a scientist named Coriolis worked
out the details of the interaction in the wind. He explained that anything
moving through a straight line laterally to the Earths spin will to the right
towards the Northern Hemisphere or to the left towards the Southern Hemisphere.
This effect is called the Coriolis Effect and is the creator of spins that create
cyclones and sometimes hurricanes.
Oceans differences in temperatures, salinity, depth and density
have a huge effect on how heat is moved around. The Atlantic Ocean is saltier
than the Pacific therefore the water is denser.
Because dense water sinks the Atlantic currents do not reach the North
Pole. If they did it would deprive
Europe of its warmth. The main heat transfer is Thermohaline circulation which
originates in slow, deep currents far below the ocean’s surface which was
discovered in 1779 by Count von Rumford. Thermohaline moves heat around and
helps to stir up nutrients as currents rise and fall making the oceans
habitable for fish and other marine life.
The oceans are crucial for life because they soak up huge volumes
of Carbon Dioxide. The sun now burns twenty five percent brighter which should
have had a catastrophic effect on the Earth, but life itself is keeping the
Earth cool. Trillions of marine organisms capture atmospheric carbon in the
form of carbon dioxide which they trap in their shells keeping the earth’s temperature
at a liveable level. If this did not
happen the earth’s temperature would rise.
When these organisms die they fall to the bottom of the ocean and turn
into limestone keeping the carbon dioxide from the atmosphere. Unfortunately
humans have a knack for burning things as a total of one hundred billion tonnes
of carbon dioxide was released into the atmosphere in 1850. Nature has saved us
from ourselves with the Earth’s oceans and forests soaking up huge volumes of
carbon dioxide. The Earths rapid increase of heat would cause many trees and
plants to die and they won’t be able to store carbon dioxide for us. But luckily nature is magnificent and the
cycle of the earth cleaning itself allows organisms to live on it.
