The Evolution of Earth

Origin of the Universe
The universe began
about 14.4 billion years
ago
The Big Bang Theory
states that, in the
beginning, the universe
was all in one place
All of its matter and
energy were squished
into an infinitely small
point, a singularity
Then it exploded

Origin of the Universe
The tremendous
amount of material
blown out by the
explosion eventually
formed the stars and
galaxies
After about 10 billion
years, our solar system
began to form

We know how the Earth and Solar System are today
and this allows us to work backwards and determine
how the Earth and Solar System were formed
Plus we can out into the universe for clues on how
stars and planets are currently being formed
Birth of the Solar System

In cosmogony, the Nebular Hypothesis is the
currently accepted argument about how a Solar
System can form
The Nebular Hypothesis

We have now discovered over two hundred planets
orbiting other stars
The processes that created our solar system have
also created an uncountable number of other solar
systems
Other Solar Systems

A large gas cloud (nebula) begins to condense
Most of the mass is in the center, there is
turbulence in the outer parts

The turbulent
eddies collect
matter measuring
meters across
Small chunks
grow and collide,
eventually
becoming large
aggregates of gas
and solid chunks

Pictures from the Hubble Space Telescope show
newborn stars emerging from dense, compact pockets
of interstellar gas called evaporating gaseous globules

Gravitational attraction causes the mass of gas
and dust to slowly contract and it begins to rotate
The dust and matter slowly falls towards the
center

After sufficient mass and density was achieved in
the Sun, the temperature rose to one million °C,
resulting in thermonuclear fusion.
H atom + H atom = He atom + energy
The Sun

A billion Year Old Earth
By 3.5 billion years ago, when the Earth was a
billion years old, it had a thick atmosphere
composed of CO2, methane, water vapor and
other volcanic gases
By human standards
this early atmosphere
was very poisonous
It contained almost no
oxygen
Remember, today our
atmosphere is 21%
oxygen

Earth is ~ 4,570,000,000 years old
The Age of the Earth
Meteorites give us access to debris left over
from the formation of the solar system
We can date meteorites using radioactive
isotopes and their decay products

Bombardment From Space
For the first half billion years of its existence, the
surface of the Earth was repeatedly hit by asteroids
and comets of all sizes
One of these collisions formed the Moon

The Early Earth Heats Up
1. Collisions (Transfer of
kinetic energy into
heat)
2. Compression
3. Radioactivity of
elements (e.g. uranium,
potassium, or thorium)
Three major factors that caused heating and melting
in the early Earth’s interior:

The Core
About 100 million years after initial accretion,
temperatures at depths of 400 to 800 km below the
Earth’s surface reach the melting point of iron
In a process called global
chemical differential, the
heavier elements, including
the melted iron, began to
sink down into the core of
the Earth, while the lighter
elements such as oxygen
and silica floated up towards
the surface

Global Chemical Differentiation
This global chemical differential was completed by
about 4.3 billion years ago, and the Earth had
developed a inner and outer core, a mantle and crust

Lithosphere: strong, rocky outer shell of the solid
Earth including all the crust and the upper part of
the mantle to a depth of ~100 km (forms the
plates)
Asthenosphere: weak,ductile layer of the mantle
beneath the lithosphere; deforms to
accommodate the motions of the overlying plates
Deep Mantle: mantle beneath the asthenosphere
(~400 to 2900 km in depth)
Outer core: liquid shell composed of mostly iron
Inner core: innermost sphere composed primarily
of solid iron
Chemical Composition of Earth

The Evolving Atmosphere
Right after its creation, the Earth is thought to
have had a thin atmosphere composed primarily of
helium (He) and hydrogen (H) gases
The Earths gravity
could not hold these
light gases and they
easily escaped into
outer space
Today, H and He are
very rare in our
atmosphere

For the next several hundred million years,
volcanic out-gassing began to create a thicker
atmosphere composed of a wide variety of gases
The gases that were released were probably similar
to those created by modern volcanic eruptions

These would include:
Water vapor (H2O)
Sulfur dioxide (SO2)
Hydrogen sulfide (H2S)
Carbon dioxide (CO2)
Carbon Monoxide (CO)
Ammonia (NH3)
Methane (CH4)

The Earth’sThe Earth’s
AtmosphereAtmosphere
Overview of the Earth’s atmosphere
Other planetary atmospheres
Vertical structure of the atmosphere
Weather and climate

Overview of theOverview of the
Earth’s AtmosphereEarth’s Atmosphere
• The atmosphere, when scaled to the size of an
apple, is no thicker than the skin on an apple.
• The atmosphere is a gas.
• The atmosphere is a fluid.
• There is a surface but no “top” – the atmosphere
gradually thins out with increasing altitude

Composition of theComposition of the
permanent gases
variable gases
trace gases
aerosols
• ..

The “dry atmosphere”: 78% N2, 21% O2,
1% Ar
• N2 is primordial – it’s been part of the
atmosphere as long as there’s been an
atmosphere
• O2 has been rising from none at all about
2.2 Gya – comes from photosynthesis
• Ar40
/Ar36
tells us that the atmosphere has
been outgassed from volcanoes

Water Vapor: H2O 0-4%
• H20 can exist in all three phases at the surface of
the Earth – solid, liquid and gas
• Liquid or solid H2O can be suspended by
atmospheric winds (clouds) or fall to the surface
(precipitation)
• VERY powerful greenhouse gas (both in vapor
form and as clouds)

The Hydrological CycleThe Hydrological Cycle
.

The Global Carbon Cycle

Aerosols
• Dust
• Sea-spray
• Microbes
Suspended particles in the atmosphere are
responsible for cloud formation: water drops
nucleate on them
Cloud Condensation Nuclei (CCN)

The Early AtmosphereThe Early Atmosphere
 Reduced primitive atmosphere(H, He, CH4,
NH3)
 Outgassing and the second atmosphere (N2,
Ar – still no oxygen!)
 The evolution of life and the atmosphere are
closely linked – life produced the oxygen
(photosynthesis) and cycles the carbon (e.g.
limestone)
 Oxidized modern atmosphere (N2, O2, CO2,
etc.)

Other AtmospheresOther Atmospheres
YES NO
Earth The Moon
Mars all the other satellites
Venus Mercury
Jupiter asteroids
Saturn
Uranus
Neptune
Pluto
Triton (Neptune’s moon)
Titan (Saturn’s moon)
The Sun

Other AtmospheresOther AtmospheresPlanet Composition Temperature Pressure
Venus CO2 96.5%, N2
3.5%
750 K 90000 mb
Earth N2 78%, O2 21%,
Ar 1%
290K 1000 mb
Mars CO2 95%, N2 2.7%,
Ar 1.6%
220K 10 mb

Vertical Structure of theVertical Structure of the
Earth’s AtmosphereEarth’s Atmosphere

Layers of the AtmosphereLayers of the Atmosphere
vertical temperature (T) profile
troposphere
stratosphere
mesosphere
thermosphere

Air PollutionAir Pollution
COPYRIGHT@GROUP -1

Air Pollution and WeatherAir Pollution and Weather
• Air pollution and weather are linked in two ways. One
way concerns the influence that weather conditions
have on the dilution and dispersal of air pollutants.
• The second way is the reverse and deals with the
effect that air pollution has on weather and climate.
• Air is never perfectly clean.
• Examples of “natural” air pollution include:
– Ash,
– salt particles,
– pollen and spores,
– smoke and
– windblown dust

Air Pollutant TypesAir Pollutant Types
• Although some types of air pollution are recent
creations, others, such as London's infamous smoke
pollution, have been around for centuries. One of the
most tragic air pollution episodes ever occurred in
London in December 1952 when more than four-
thousand people died.
• Air pollutants are airborne particles and gasses that
occur in concentrations that endanger the heath and
well-being of organisms or disrupt the orderly
functioning of the environment.
• Pollutants can be grouped into two categories:
– (1) primary pollutants, which are emitted directly from
identifiable sources, and
– (2) secondary pollutants, which are produced in the
atmosphere when certain chemical reactions take place
among primary pollutants.

Primary PollutantsPrimary Pollutants
The major primary pollutants include:
– particulate matter (PM),
– sulfur dioxide,
– nitrogen oxides,
– volatile organic compounds (VOCs),
– carbon monoxide, and
– lead.

Sources of Outside AirSources of Outside Air
PollutionPollution
Combustion of gasoline and other hydrocarbon fuels in
cars, trucks, and airplanes
Burning of fossil fuels (oil, coal, and dinosaur bones)
Insecticides
Herbicides
Everyday radioactive fallouts
Dust from fertilizers
Mining operations
Livestock feedlot

Secondary PollutantsSecondary Pollutants
• Atmospheric sulfuric acid is one example of a
secondary pollutant.
• Air pollution in urban and industrial areas is often
called smog.
• Photochemical smog, a noxious mixture of gases
and particles, is produced when strong sunlight
triggers photochemical reactions in the
atmosphere.
• The major component of photochemical smog is
ozone.
• Although considerable progress has been made in
controlling air pollution, the quality of the air we
breathe remains a serious public health problem.

Controlling Air PollutionControlling Air Pollution
through Regulationsthrough Regulations
• Economic activity, population growth, meteorological
conditions, and regulatory efforts to control
emissions, all influence the trends in air pollution.
• The Clean Air Act of 1970 mandated the setting of
standards for four of the primary pollutants—
– particulates,
– sulfur dioxide,
– carbon monoxide, and
– Nitrogen
– as well as the secondary pollutant ozone.

Have Regulations Helped?Have Regulations Helped?
• In 1997, the emissions of the five major
primary pollutants in the United States were
about 31 percent lower than 1970.
• In 1990, Congress passed the Clean Air Act
Amendments, which further tightened
controls on air quality.
• Regulations and standards regarding the
provisions of the Clean Air Act Amendments
of 1990 are periodically established and
revised.

Air Pollution OccurrencesAir Pollution Occurrences
• The most obvious factor influencing air pollution is
the quantity of contaminants emitted into the
atmosphere.
• However, when air pollution episodes take place,
they are not generally the result of a drastic increase
in the output of pollutants; instead, they occur
because of changes in certain atmospheric
conditions.
• Two of the most important atmospheric conditions
affecting the dispersion of pollutants are:
– (1) the strength of the wind and
– (2) the stability of the air.

Air MixingAir Mixing
• The direct effect of wind speed is to influence the
concentration of pollutants.
• Atmospheric stability determines the extent to which
vertical motions will mix the pollution with cleaner air
above the surface layers.
• The vertical distance between Earth's surface and the
height to which convectional movements extend is
called the mixing depth.
• Generally, the greater the mixing depth, the better the
air quality.

InversionsInversions
• Temperature inversions represent a situation in
which the atmosphere is very stable and the mixing
depth is significantly restricted.
• When an inversion exists and winds are light,
diffusion is inhibited and high pollution concentrations
are to be expected in areas where pollution sources
exist.
• Surface temperature inversions form because the
ground is a more effective radiator than the air above.
Inversions aloft are associated with sinking air that
characterizes centers of high air pressure
(anticyclones).

This is an example
of temperature
profile for a
surface inversion.
Temperature-
profile changes in
bottom diagram
after the sun has
heated the surface.

Acid PrecipitationAcid Precipitation
• In most areas within several hundred
kilometers of large centers of human activity,
the pH value is much lower than the usual
value found in unpopulated areas.
• This acidic rain or snow, formed when sulfur
and nitrogen oxides produced as by-products
of combustion and industrial activity are
converted into acids during complex
atmospheric reactions, is called acid
precipitation.

Acid Precipitation (cont.)Acid Precipitation (cont.)
• The atmosphere is both the avenue by which
offending compounds travel from sources to the sites
where they are deposited and the medium in which
the combustion products are transformed into acidic
substances.
• Beyond possible impacts on health, the damaging
effects of acid precipitation on the environment
include the lowering of pH in thousands of lakes in
Scandinavia and eastern North America.
• Besides producing water that is toxic to fish, acid
precipitation has also detrimentally altered complex
ecosystems by many interactions at many levels of
organization.

Elements of WeatherElements of Weather
air temperature
air pressure
humidity
clouds
precipitation
visibility
wind

ClimateClimate
average weather
• time-average
• regional (spatial) average
extremes
trends

WeatherWeather
Weather isWeather is the dynamical waythe dynamical way
in which the atmospherein which the atmosphere
maintains the equilibriummaintains the equilibrium
climate.climate.

A Look at a Weather MapA Look at a Weather Map
wind speed and direction
cyclones and anticyclones
fronts

A Satellite’s View of theA Satellite’s View of the
WeatherWeather

Computers and
Weather
forecasting
eather forecasting copyright@chauhanama

Commonly AcceptedCommonly Accepted
DefinitionsDefinitions
Weather refers to the current atmospheric
conditions (including temperature, precipitation,
wind, humidity, barometric pressure) at a
particular time and place.
Climate refers to the general weather patterns
expected in a given area (sometimes based on
the 30 year average weather). Climate may also
be applied more generally to large-scale weather
patterns in time or space (e.g., an Ice Age
climate or a tropical climate).

Menu
Weather forecasting
Explanation
Overview picture
Data collection
Sensors
Data logging
Weather station
Radiosonde
Satellites
Radar
Weather ships
Supercomputers
Parallel ProcessingSoftware
Pressing Weather forecasting on any slide
will bring you back to this menu

During the last two decades the Met Office has
used state-of-the-art supercomputers
for numerical weather prediction and more
recently, also for predictions of global climate.
Weather forecasting
This is a picture of a supercomputer

Weather forecastingWeather forecasting
Weather forecasters are helped
by
several things. These include:-
The computer makes millions of calculations.
1. The computer’s advice
2. Information from radar
3. Information from satellite pictures
The sums are called differential equations
Before the computer can do the calculations,
data has to be collected first.

Weather forecasting
Collecting data on the weather is very important.
Without the data, the computer could not do
the calculations that enable it to
make weather predictions.
The next slide shows where the data comes from.
It also shows where the forecasts are sent.
Always remember that the forecasters are highly
trained people and they use their judgement
and expertise to make their forecast
based on the information the computer
gives them and the information from the radar
and the satellite pictures.

Supercomputer
Radio-sonde
Weather ship
and weather buoys
Satellites
Radar
Weather forecasting
Weather
stations

Forecaster
Supercomputer
Global forecast services
Aviation
Shipping
National and International
Forecast Services up to
7 days ahead.
Radio-sonde
Weather ship
and weather buoys
Satellites
Radar
Weather forecasting
Weather
stations

Weather forecasting
Data is collected continuously for the
computer from the following:-
1. Weather stations
2. Automated weather
stations
3. Satellites
4. Radar
5. Radiosondes
6. Weather ships
7. Mini-radiosondes
8. Radar
9. Aeroplanes
10. Drifting buoys

Weather forecasting
The data measurements are made by sensors
A sensor is a transducer which responds to
some physical property such as pressure,
temperature, rate of flow.
A transducer is an electronic component
which converts energy from one form to another.
We want the transducers to send signals
to the computer in the Met. Office.

1. Temperature .. Air, surface and subsurface
temp.
2. Atmospheric Pressure
3. Wind speed
4. Wind direction
5. Humidity
6. Rainfall
Weather forecasting
7. Sunshine
The measurements needed include:-

Weather forecasting
Data logging is the capture and
storage of data for future use.
All the measurements from the sensors are
stored because:-
So data logging is used in weather forecasting.
• The computer processes the data in batches
• People need to refer back to weather data
for
many reasons

Mountain
effects
Formation of
clouds
Formation
of rain and
snow
Friction
Radiation
from the
earth
Radiation from
the
atmosphere
Radiation from the sun
Evaporation
and
heat
exchange
The atmosphere is split up into a 3-D grid.
Each land based grid is about 60km.
Sea
Weather forecasting

Sea
We need to measure pressure,
temperature,
wind speed and wind directions as
well as rainfall, cloud cover,etc in as
many grid spaces as possible
Weather forecasting

Sea
Weather forecasting
Weather stations are used here.

temperature,
well as rainfall, cloud cover,etcRadiosondes
are used up
here.
20 km
Sea
er

Sea
temperature,
well as rainfall, cloud cover,etc
Minisonde
s are
used
here.
5 km
Everest is 8.85 Kms high.
So we have shown you a very high mountain!
Weather

Sea
temperature,
Aeroplane
s send
data too.
10 km
Weather forecasting

Sea
temperature,
Satellites
send data
too.
36,000km
Weather forecasting
The Geostationary satellites are
36,000 Km above earth.

There are two types of satellites.
• Geostationary. These stay in the same spot.
They orbit the earth at exactly the same speed
as
the earth rotates. They are very high above
earth -
36,000 km.5 geostationary satellites are enough to give
global coverage.
Weather forecasting
• Polar orbiting. These orbit the earth about 14
times a day. They orbit at 1000 km above the
earth.

Weather forecasting
A Geostationary
satellite stays in
the same place
with respect to
earth all the time
A Polar orbiting satellite moves
above the earth’s surface

Weather forecasting
Picture courtesy of the European
Organisation for the Exploitation of
Meteorological Satellites and photo
courtesy of Dundee University.
The URL ( Uniform Resource Locator )
www.sat.ac.in/tour.html will tell you more
about satellites if you are interested
Meteosat: a
geostationary
satellite. It sends
microwave signals
back to earth.
The satellite’s signals are received
by antennae.
©Eumetsat 2003

This is a Polar Orbiting
Satellite
Weather forecasting
The satellite can take readings across the
entire earth during the course of one day.

Sea
Weather forecasting
Radar systems are used here.
Radar stands for radio detection and
ranging. Radio waves are transmitted, when
they hit a rain cloud they bounce back to
earth and measurements can be taken.

Sea
Weather
There are weather ships out to sea
There are also buoys taking weather
measurements in the sea

This is a Weather ship.
Weather
Buoys are used at sea
more than weather
ships these days.
They send their data
automatically back to
the computer.
Thanks to www.gdfcartophily.co.uk

Weather forecasting
We store Gigabytes (one thousand million bytes 109
)
of data on the Hard drives in our school.
Supercomputers have stores for Terabytes of data.
A Terabyte is
one million, million bytes, 1012
bytes.
A supercomputer is a very large computer,
which works very, very fast. It is about 1000
times more powerful than a PC.
It also has an
enormous store
(memory).

Weather forecasting
Parallel processing splits jobs up and gives
different processors tasks. These all have to
be brought together.
When a computer uses
several processors in parallel
it is known as
parallel processing.
Parallel processing is difficult to program

Massively Parallel Processor machines.
MPP systems use a distributed hierarchy of
memory. This just means that they have to have a
system of accessing the memory available.
MPP systems rely on very high bandwidth
communications to move data between
memory and between different processors
so that they are all kept busy during program
execution.
Weather forecasting

Weather forecasting
The weather forecasts are run in batch mode.
Batch mode is when all the jobs or data to be
processed are put together for processing and
then run together.
The batches are done by a piece of software
produced by the same company CRAY that
makes the computers. It is known as the NQS,
the Network Queueing System.

Key TerminologyKey Terminology
“Natural” air pollution Primary pollutants
Secondary pollutants Smog
Photochemical smog Photochemical
reactions
Ozone Clean Air Act (1970)
Mixing depth Inversion
Surface inversion PARALLEL computing
Acid Precipitation Meteorites
Radiosonde Nebular hypothesis

Weather forecasting
Copyright @amay
GROUP -1
FC – SCI. AND LIFE
I would like to thank all my
team members who
supported me in making this
presentation a success.

The Evolution of Earth

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