the evolution of earth

The Evolution of the Earth

Origin of the UniverseThe 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


Protostar

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

Birth of the Solar System

Size of the Planets

A billion Year Old EarthBy 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 systemWe can date meteorites using radioactive isotopes and their decay products

Bombardment From SpaceFor 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 CoreAbout 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 DifferentiationThis 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 AtmosphereRight 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

The Evolving AtmosphereFor 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 Evolving Atmosphere

The Earth’s The Earth’s AtmosphereAtmosphere

Overview of the Earth’s atmosphereOther planetary atmospheresVertical structure of the atmosphereWeather and climate

Overview of the Overview 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 the Composition of the AtmosphereAtmosphere

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

Layers of the AtmosphereLayers of the Atmosphere

vertical temperature (T) profiletropospherestratospheremesospherethermosphere

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 Air Sources 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 Pollution Controlling 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).

Inversion

This is an example of temperature profile for a surface inversion.

Temperature-profile changes in bottom diagram after the sun has heated the surface.

An Inversion

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 temperatureair pressurehumiditycloudsprecipitationvisibilitywind

ClimateClimate

average weather• time-average• regional (spatial) average

extremestrends

Weather Weather

Weather is Weather is the dynamical way the dynamical way in which the atmosphere in which the atmosphere maintains the equilibrium maintains the equilibrium

climate.climate.

A Look at a Weather MapA Look at a Weather Map

wind speed and directioncyclones and anticyclonesfronts

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

Computers and Weather

forecasting

Weather forecasting copyright@chauhanamay

Commonly Accepted Commonly 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 collect ion

Sensors

Data logging

Weather stat ion

Radiosonde

Satell i tes

Radar

Weather ships

Supercomputers

Parallel ProcessingSoftware

Pressing Weather forecasting on any slide wil l br ing you back to this menu

During the last two decades the Met Office hasused state-of-the-art supercomputersfor numerical weather prediction and morerecently, also for predictions of global cl imate.

Weather forecasting

This is a picture of a supercomputer

Weather forecastingWeather forecasting

Weather forecasters are helped by several things. These include:-

The computer makes mill ions of calculations.

1. The computer’s advice

2. Information from radar

3. Information from satell i te pictures

The sums are called differential equations

Before the computer can do the calculations, data has to be collected f irst.

Weather forecasting

Collecting data on the weather is very important.

Without the data, the computer could not do the calculat ions that enable it tomake 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 highlytrained people and they use their judgementand expertise to make their forecastbased on the information the computergives them and the information from the radarand the satell i te pictures.

Supercomputer

Radio-sonde

Weather shipand weather buoys

Satell i tes

Radar

Weather forecasting

Weatherstations

Forecaster

Supercomputer

Global forecast services

Aviation

Shipping National and International Forecast Services up to

7 days ahead.

Radio-sonde

Weather shipand weather buoys

Satell i tes

Radar

Weather forecasting

Weatherstations

Weather forecasting

Data is collected continuously for the computer from the following:-

1. Weather stat ions2. Automated weather

stations 3. Satell i tes 4. Radar 5. Radiosondes 6. Weather ships 7. Mini-radiosondes 8. Radar 9. Aeroplanes10. Drif t ing 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 f low.

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. Off ice.

1. Temperature .. Air, surface and subsurface temp.

2. Atmospheric Pressure

3. Wind speed

4. Wind direction

5. Humidity

6. Rainfal l

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

FrictionRadiation from the

earth

Radiation from the atmosphere

Radiation from the sun

Evaporation and

heat exchange

The atmosphere is spli t 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 stat ions are used here.


wind speed and wind directions as well as rainfall, cloud cover,etcRadiosondes

are used up here.

20 km

Sea

Weather forecasting

Sea


wind speed and wind directions as well as rainfall, cloud cover,etc

Minisondes are used

here.

5 km

Everest is 8.85 Kms high. So we have shown you a very high mountain!

Weather forecasting

Sea



Aeroplanes send

data too. 10 km

Weather forecasting

Sea



Satell i tes send data

too.

36,000km

Weather forecasting

The Geostationary satell i tes are 36,000 Km above earth.

There are two types of satell i tes .

• 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 satell i tes are enough to give

global coverage.

Weather forecasting

• Polar orbit ing. These orbit the earth about 14 t imes a day. They orbit at 1000 km above the earth.

Weather forecasting

A Geostationary satell i te stays in the same place with respect to

earth all the t ime

A Polar orbit ing satell i te moves above the earth’s surface

Weather forecasting

Picture courtesy of the European Organisation for the Exploitation of Meteorological Satell i tes and photo

courtesy of Dundee University.

The URL ( Uniform Resource Locator ) www.sat.ac.in/tour.html wil l tel l you more

about satell i tes if you are interested

Meteosat: a geostationary satell i te. I t sends microwave signals back to earth.

The satell i te’s signals are received by antennae .

©Eumetsat 2003

This is a Polar Orbit ing Satell i te

Weather forecasting

The satell i te 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 forecasting

There are weather ships out to sea

There are also buoys taking weathermeasurements in the sea

This is a Weather ship.

Weather forecasting

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 mil l ion bytes 10 9) of data on the Hard drives in our school.Supercomputers have stores for Terabytes of data.

A Terabyte isone mil l ion, mil l ion bytes, 10 12 bytes.

A supercomputer is a very large computer, which works very, very fast. I t is about 1000 t imes more powerful than a PC.

It also has an enormous store (memory).

Weather forecasting

Parallel processing splits jobs up and gives dif ferent processors tasks. These all have to

be brought together.

When a computer usesseveral processors in parallel

it is known asparallel processing.

Parallel processing is diff icult to program

Massively Parallel Processor machines.

MPP systems use a distr ibuted 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. I t 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 @amayGROUP -1FC – SCI. AND LIFE

I would l ike to thank all my team members who supported me in making this presentation a success.

the evolution of earth

Science