Stars to fossil fuels
Big bang.
Dark matter, Dark energy.
Stars.
Fundamental forces.
Einstein's equation.
Energy density.
Our Sun.
Elements.
Earth.
Life.
Energy transfer.
Oxygen.
Coal.
Petroleum and natural gas.
Fossil fuels.
Everything in the universe was formed in an instant 13.8 billion years ago, with a Big Bang.
The universe is a closed system, and nothing can be added to it.
The entire history of the cosmos has been one of recycling and renewal.
All the energy that we use on Earth, from the fuel we burn, to the food we eat,
is the simply the latest link in a series of transitions and exchanges that began with the Big Bang.
The first moment is called the Planck epoch.
There are four fundamental forces that govern the universe.
- The weak nuclear force.
- The strong nuclear force.
- Gravity.
- Electromagnetism.
During the Planck epoch, these fundamental forces became distinct and independent.
In this process gravity weakened significantly.
The energy from this separation drove the fleeting next phase transition.
This is called the Grand Unification Epoch.
This phase was a time of cosmic inflation.
During cosmic inflation the universe doubled in size, at least 90 times.
It went from the sub atomic size, to the size of a golf ball almost instantaneously.
After inflation the expansion was much slower.
Even before it was a second old, the universe had grown from 10 to the power of minus 25 meters,
to 10 to the power of plus 25 meters, in diameter.
It grew from a size much smaller than the nucleus of an atom, to over 1 billion light years across.
Our own milky way galaxy is only 100 thousand light years in diameter.
During cosmic inflation, the universe was using heat very fast.
This cooling allowed particles to form.
By the time the universe was one second old,
it was no longer hot enough or dense enough to create protons and neutrons.
Their ratio was fixed for eternity.
Four minutes later, the production of atomic nuclei was frozen.
There was only radiation until the first generation of stars began to form 380,000 years later.
The early universe was a hot dense soup of super heated particles,
moving around in complete darkness.
We do not know everything about the early universe.
We are learning more and more about the early universe.
In 2013, the Planck telescope mapped the cosmic microwave background.
This provided the most precise measure, currently known, for the age of the universe.
The observable universe accounts for just 5% of the total mass.
The 95% that is missing is difficult to track down.
Scientists currently guess that 27% of this elusive material is made up of dark matter.
Dark matter is completely undetectable.
It comprises of Weakly Interacting Massive Particles, called WIMPs.
WIMPs don’t interact with anything.
The other component of dark matter is Massive Astrophysical Compact Halo Objects, or MACHOs
MACHOs float through the universe emitting neither light nor radiation.
They have no association with any visible stellar object.
Scientists are searching actively for dark matter.
But so far its presence is known only indirectly through its gravitational influence.
We can feel dark matter’s effects.
This is what allowed galaxies to form.
It is dark matter that is stopping them from flying apart.
Ordinary matter and dark matter are estimated to constitute less than a third of the universe.
68.3% of the total mass energy of the universe is still missing.
Scientists believe that this shortfall is made up of dark energy.
The effects of dark energy was first noticed in 1998.
Scientists discovered that something was overpowering gravity,
and causing the universe’s rate of expansion to increase.
Apart from this, we do not know much about dark energy.
Stars comprise of ordinary matter.
There are billions and billions of stars in the universe.
There is an estimated 10 to the power of 24 stars in the universe.
Stars come in a wide range of colours, sizes and brightness.
All stars are made up of just two elements, hydrogen and helium.
Hydrogen and helium together account for all the 97% of visible matter in the universe.
All the other matter like nitrogen, oxygen, iron, copper etc., are rare materials.
Stars burn brightly because they harness the power of nuclear fusion.
Nuclear reactors that we have built work by nuclear fission.
In nuclear fission atoms are split to release vast amount of energy.
In stellar fusion the opposite happens.
The temperature in the core of a star is very high.
This causes hydrogen atoms to move and collide with each other,
and fuse to form helium.
The helium atoms have slightly less mass than the two hydrogen atoms that created them.
The mass that is lost, escapes in the form of radiation.
Energy and mass should be viewed as two sides of the same coin.
All objects are moving through space.
The Earth is moving at 67000 miles per hour, in its orbit around the sun.
The whole solar system is orbiting our milky way galaxy at 514000 miles per hour.
The milky way galaxy itself is moving through space.
If we add all these, we are moving at 3,240,000 miles an hour, even when we are asleep.
We don’t feel that we are moving, because speed is relative.
We feel movement only when there is an increase or decrease in speed.
A objects mass is a measure of its resistance to the change of speed.
The forces employed to get objects to change their speed, exchange energy.
Objects like a plant cell, a tree, an atom or a star, can be viewed as a closed physical system.
Scientists define energy as the ability of a closed physical system to do work, on other physical systems.
The work takes the form of a force that acts over time and space.
This is equivalent of a pull or push against the four fundamental forces of nature.
These forces act upon everything all the time.
Even as we read a book, the force of gravity is pulling us down,
and the force of electromagnetism is responsible for generating the light for us to read.
The two remaining forces work at an atomic level, and cannot be felt.
The strong nuclear force is what holds atoms together.
Without it nothing would exist.
The weak nuclear force is responsible for the radioactive decay,
that initiates the process of hydrogen fusion in the sun.
No weak nuclear force means no fusion, which means no stars, no sun and no life on Earth.
E=mc squared is the famous Einstein’s equation.
This equation shows us how energy and mass are related.
The total energy in any object, whether it is in hydrogen atom, or a lump of coal,
is identified with its mass.
Like mass energy cannot be created or destroyed.
It can be only converted from one form to another.
For example, the chemical energy of petrol is converted into,
kinetic energy within an internal combustion engine.
The binding energy of two hydrogen atoms is converted into radiation during fusion.
The mass of the system does not change through out the transformation process.
If we can weigh it accurately, the mass of a freshly baked loaf of bread,
will be higher than an identical cool one, because it has more energy.
There is no absolute measure of energy.
Only its transition from one state to another can be described.
Even this can be only on relative terms.
The conventional method of measurement is calorimetry.
This is based on temperature or the intensity of radiation.
The energy transferred is expressed in a variety of units,
such as ergs, calories, joules, or kWh, depending on use.
kWh is used to measure electricity bills.
Calories is used to measure energy content of food.
When discussing fuels, it is more helpful to measure in energy density.
Energy density is the amount of useful energy stored per unit volume or mass.
For example, if we compare hydrogen and petroleum, hydrogen contains far more energy per Kg,
compared to petroleum.
In practical terms petroleum is a vastly more effective fuel because,
even in liquid form, hydrogen has lower energy density.
This effectively means that petrol will give more Kilometers per litre.
Energy can take several different forms.
It can be chemical, nuclear or magnetic.
It can be mechanical, radiant or thermal.
All forms of energy can be divided into two groups.
Kinetic energy is the energy, an object has due to its motion.
Potential energy is the energy contained in a physical system.
A moving car has kinetic energy.
The petrol in the gas tank has potential energy.
Petrol has chemical energy which is converted to thermal energy,
which drives the pistons in the engine, to produce mechanical energy.
When energy is converted from one form to another usually some energy leaks away as heat.
Einstein’s E=mc squared equation,
shows us that even a tiny amount of matter can produce large amounts of energy.
The speed of light is a very large number.
It is 2.99 into 10 to the power of 8 meters per second.
This is why fusion is such an efficient means of producing energy.
In our own Sun, every second 600 million tonnes of hydrogen fuses to create helium.
This releases 4 million tonnes of energy in the process.
This has been happening for 4.6 billion years and will continue for several billion years more.
If the Sun produced the same amount of energy, burning coal,
then its lifespan would be very much shorter.
Burning coal is a conversion of molecular bonds, into radiation.
Burning coal yields 25 kilojoules per gram.
This yield comes by breaking the carbon to carbon, and oxygen to oxygen molecular bonds,
and forming carbon to oxygen bonds.
This is not very efficient compared to converting mass directly to energy,
which would yield 4 billion times more energy.
This amounts to 8.9 into 10 to the power of 10 kilojoules per gram.
3 Kg of coal can produce 20 kilowatt hours.
This is enough to heat a small house for one hour.
It releases energy at the rate of 7 kilowatts or 7 kilojoules per second.
The Sun’s mass is 2 into 10 to power of 23 Kg.
It releases energy at the rate of 4 into 10 to power of 23 kilowatts.
If the Sun was burning coal, instead of converting mass into energy,
it would last only for 4000 years, instead of several billion.
This is why fusion is the most common form of energy production, in the visible universe.
It is able to power every star for billions of years.
Stars last for a long time, but not forever.
They are born, live, and die.
How long they live, and how they die depends on what kind of star they are.
Our own Sun is an unremarkable G-dwarf star.
As it grows older, it will become smaller, brighter, and hotter.
In 3 billion years time, it will be 40% hotter than it is today.
It will evaporate all the water in our oceans, and bring an end to all life on the planet.
In 5 billion years time, its core will collapse, as it runs low on fuel.
It will expand to become a massive red giant.
It will engulf all the inner planets, Mercury, Venus, Earth and Mars.
Eventually it will throw of its outer matter in a mass of gas and dust.
It will leave behind a white dwarf to twinkle over trillion of years.
Bigger stars live fast, burn brighter, and die younger in supernovae.
During their lives, stars provide the universe with light and heat.
Their death is also productive.
We do not know how long an atom can survive.
They are remarkably durable and estimated lifespan is 100 billion trillion years.
In the universe stars are dying all the time.
They are recycled and new stars are being born all the time.
The atom is at the heart of the cosmic recycling scheme.
Stellar nucleosynthesis is the process that creates new atomic nuclei,
from existing proton and neutrons within stars.
This is how all other primordial elements like carbon to iron got produced.
As stars get older and hotter, fusion starts to produce heavier elements,
from the hydrogen and helium nuclei.
All the elements that have an atomic number more than iron, upto plutonium,
are produced by explosive nucleosynthesis, which occur during supernova.
Recycling begins as soon as the dying star explodes.
It leaves clouds of superheated atoms and particles.
Gravity causes these clouds to condense.
As the matter becomes compact, it heats up and eventually becomes so hot,
that it ignites, and the new star is born.
This process has been going on as long as the universe itself.
Our Sun is a third generation star.
This means that every atom in our solar system has been through this process twice before.
The solar system began its life as one of these clouds of cosmic dust,
called the solar nebula.
About 4.6 billion years ago that nebula coalesced under the force of gravity,
and began spinning into a flattened disk.
99% of all the material was compressed into a proto-sun.
The rest of the materials formed a disk of rings.
Close to the sun only rock and metals could survive the heat.
This is why the inner planets from Mercury, Venus, Earth and Mars,
are made up of heavier material, predominately iron.
The outer planets Jupiter, Saturn, Uranus, Neptune are mostly gaseous.
Eventually, the Sun became hot enough and dense enough to ignite.
The ancient solar system was a chaotic place where astral collusions were common.
When the Earth was just 100 million years old it collided with another proto-planet called Thea.
Thea was about the same size as Mars.
The collision knocked the Earth of its axis, giving it an axial tilt.
This axial tilt from 22.1 to 24.5 degrees gives us the seasons.
This in turn provided the stimulus for evolution to take place.
It also increased the velocity of rotation.
This reduced the daily variation in temperature.
It changed the surface composition of the planet, enriching it with silica and other minerals.
Most important, it formed the Moon.
Earth is unusual because it is the only inner planet with a moon.
Venus and Mercury do not have a moon.
The twin moon of Mars are just tiny rouge asteroids captured by the gravity of Mars.
Our own moon is very large.
It is 27% of the Earth’s size.
Without the moon there will be no tidal pools.
Scientist believe that tidal pools are essential for formation of complex life.
The moon also initiated plate tectonics, which allowed replenishment of nutrients,
for the primitive life forms to feed on.
The Earth orbits the Sun, in what the scientist call the habitable zone.
Here the planet with sufficient atmospheric pressure can maintain liquid water on its surface.
Water on Earth probably arrived in the early part of its history,
as a result of collision with stray comets and other icy celestial bodies.
The Earth was big enough to hold on to its atmosphere.
On smaller planets gravity is insufficient to hold on to surrounding gases.
Planets with out an atmosphere are prone to enormous changes in temperature.
In Mercury, which has no atmosphere,
the temperature fluctuates between 400 degree centigrade during the day,
and minus 200 degree centigrade during the night.
This diurnal variation makes it impossible to sustain substantial oceans.
Smaller planets tend to have rougher surfaces with larger mountains and deeper canyons.
It seems that a set of coincidences made all the conditions on Earth just right for life.
This observation is called ‘Goldilocks Enigma’ .
Some people believe that the universe itself has been fine tuned for life to exist.
By luck or by design, as far as we know, Earth is the only place that life is known to exist.
How it came to exist is yet another mystery.
Evidence suggest that life on Earth has been there for 3.7 billion years.
There is no standard model of its genesis.
Most of the models conquer with the Oparin-Haldane hypothesis.
This posits that primordial soup of organic molecules could be created in the oxygen free atmosphere,
of early Earth, through the action of sunlight.
Beyond this, there is no proven theory.
What constitutes life is another grey area.
Living things are distinguished that they have signalling and self sustaining processes.
The earliest and simplest forms of life are the prokaryotes.
There are a group of tiny organisms that lack a nucleus.
They include bacteria, and a whole host of organisms called archea.
Archea though similar to bacteria, belong to a different family.
Probable fossils have been found dating back to 3.5 billion years.
Viruses are even smaller than prokaryotes.
They are possibly even older.
Their origin is unclear because they do not fossilise.
However they are found wherever life exists.
Viruses have genes.
They reproduce via natural selection, and by making multiple copies of themselves.
They do not have a cellular structure.
They do not have metabolism, - the set of chemical reactions that takes place in living organisms.
They rely on a host for metabolism.
Abiogenesis is the theory, that life is created from non living matter.
Some scientist believe that life exists throughout the universe,
and is distributed by meteors, comets and astroids.
This is called panspermia.
There is not enough evidence yet to substantiate it.
No one has been able to create life in a laboratory.
As of now we believe that cellular carbon based life emerged on Earth,
3.7 billion years ago and has thrived ever since.
Life is an essence of highly complex process of energy transfer.
The cells that makeup all living things are life basic functional units.
They are also the vectors for all energy transfer.
Cells are tiny bags of plasma enclosed by a membrane.
The human body contains about 10 trillion of them.
The cell membrane is a significant accomplishment of evolution.
Membranes are semi-permeable.
They control the flow of substances in and out of the cell.
Membranes are made of fat like lipid molecules.
The membrane is embedded with a variety of proteins.
The nucleus has the DNA of the cell.
DNA generates RNA which gives the cell, its instructions.
This determines what type of cell it is,
like skin, bone, blood, brain etc,.
The actual work is done by the organelles, which are miniature organs.
The ribosomes process amino acids.
The centrosome organise the cell and maintain its structure, the cytoskeleton.
The vacuoles store food, and get rid of waste.
An important organelle is the mitochondria in animal cells, and chloroplast in plant cells.
Chloroplast make carbohydrates, the basic fuel for all life forms.
Mitochondria burn carbohydrates to make adenosine triphosphate or ATP.
ATP is the energy vector that powers the processes of life.
Mitochondria generate much of these cells supply of chemical energy by converting,
sugars, fatty acids, and nucleotides into ATP.
ATP is called the molecular unit of currency.
It is a vehicle by which chemical energy is transported for use by the metabolism.
The metabolic processes use ATP as an energy source, and convert it back to its components.
ATP is continuously recycled in organisms.
The human body contains about 250 grams of ATP,
it turns over its own weight in the substance each day.
Chloroplasts are found in the cells of plants.
It is what gives these life forms, their distinctive green colour.
Chloroplasts produce ATP by capturing and converting light energy.
This process is called photosynthesis.
In photosynthesis sunlight is used to convert carbon dioxide to organic compounds like sugars.
This process releases oxygen.
Photosynthesis is vital for all aerobic or oxygen breathing life on the planet.
It regulates the levels of oxygen in the atmosphere.
It is the primary source of energy for almost all life on the planet.
Plants use sunlight to produce food.
Animals consume the food produced by plants.
In general we can think of food as captured sunlight.
The earliest photosynthetic microbes, lived in the ancient oceans,
surrounding the singular continent of Pangaea.
There was no life on land at that time.
These organisms transformed the atmosphere by discharging oxygen into it.
In the early stages the oxygen remained water bound.
Iron exists in two oxidation states, Ferrous oxide, and Ferric oxide.
Ferrous oxide is water soluble.
Ferric oxide is what we know as rust.
The oxygen produced converted the ferrous oxide to ferric oxide.
After all the ferrous oxide has been oxidised, oxygen started building up in the atmosphere.
Eventually, it reached a homeostatic state of 21% in the atmosphere.
This is the amount of oxygen what we have today.
Photosynthetic microbes are also responsible for creating all the iron ore that we use.
It is interesting to note that coal and iron ore, that drove the industrial revolution,
are merely relics of a much earlier energy revolution, involving photosynthesis.
We cannot find coal or iron ore in dead planets.
Photosynthesis provides us more than just food.
Its rate of energy capture is immense.
It is about 90 terawatts per year.
This is 6 times more than the current power consumption.
Photosynthesis is also the source of the carbon in all the organic compounds,
within the body of every living organisms.
Photosynthetic organisms convert 115 billion tons of carbon into biomass every year.
Photosynthetic organisms are photoautotrophs.
They are repositories of energy.
What is not consumed as food is often preserved after the plants die.
When we burn a log of wood, we are tapping into this repository of stored energy.
The same is true when we burn a lump of coal.
The only difference is that the energy in the lump of coal is much older.
Coal is the most abundant of the fossil fuels.
Fossil fuels include petroleum and gas.
These fuels are the fossil remains of dead plants and animals.
The energy built up when these organisms were alive, are stored in their fossils.
These organisms expired long ago, typically tens of millions years ago.
Some of them could have lived more than 650 million years ago.
Because they were once living things, fossil fuels contain a high percentage of carbon.
Fossil fuels were found from the remains of organisms,
by exposure over millions of years, to heat and pressure within the Earth’s crust.
In the case of coal, these organisms were the trees in the forest 300 million years ago.
This was the carboniferous period, when dense forests covered almost the entire land.
The wide shallow seas of this period provided ideal conditions for coal to form.
Natural processes like flooding caused these forests to get buried under the soil.
A combination of mud and acidic water prevented decomposition from taking place.
Instead the trees were covered with increasing layers of soil, sinking deeper and deeper into the Earth.
All the carbon was trapped in immense peat bogs.
This was covered and buried by further sediments.
Over millions of years the pressure and temperature increased,
and the vegetation became converted to coal.
This process is called carbonisation.
Petroleum and natural gas are formed by remains of algae and zooplankton,
that lived in ancient oceans.
When these organisms died, there bodies settled in large quantities,
at the bottom of seas and lakes, where oxygen was scarce.
The absence of oxygen prevented normal decomposition from taking place.
The organic matter was preserved, and just like coal was buried under layers of sediment.
Over millions of years heat and pressure built up.
This caused a chemical transformation of the organic material, into a waxing material called Kerogen.
This material is found in oil shales in Canada and Brazil.
Much of this kerogen was subjected to further heat and pressure.
This converted them to liquid hydrocarbons such as natural gas,
and liquid hydrocarbons such as petroleum.
This process is called as catagenesis.
Burning fossil fuels releases this ancient energy.
It also emits carbon dioxide.
We emit about 22 billion tons of carbon dioxide every year.
Plants absorb some of this carbon dioxide.
Plants and other natural processes can absorb only half of what we emit.
This means that every year, there is a net increase of 11 billion tons of atmospheric carbon dioxide.
Carbon dioxide is one of the green house gases, that contribute to global warming.
Global warming is the increase in surface temperature of the Earth.
It has major adverse effects for all of us.
Fossil fuels are not renewable.
They take millions of years to form.
It has taken 600 million years to produce all the coal, petroleum and natural gas in the world.
We burn about 20 million years of this fossil fuels every year.
The development of cells that could photosynthesise,
was the first effective mechanism to capture sunlight.
Fossilisation ensured that this could be stored indefinitely.
We are now harvesting nature’s labour for millions of years.
The food we eat, and the fossil fuels we burn are nothing but captured sunlight.
Energy transfer began with the big bang.
It continued through nuclear fusion reactions of three generations of stars.
This was followed by photosynthesis of ancient plant life.
Millions of years later, we casually consume this as fuel.
Estimates of how much of this fossil fuel reserves are left varies by a few decade.
What is clear however is that these reserves are limited, and it will take millions of years to renew them.
It is quite obvious that we will run out of fossil fuels very soon.
We need to explore alternative sources to meet our energy needs.