Download - Universe for high school students
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Universe
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The most incomprehensible thing about the Universe is that; it is comprehensible.
- Albert Einstein
The Universe is comprehensible because it is governed by scientific laws; that is to say, its behaviour can be modelled.
- Stephen Hawking
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Part -I• How and Where did the Universe come
from and what awaits its final fate.
Part –II• Human Journey in understanding
Universe since last 3000 years
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Part –I
How and where did the UniverseUniverse come from and what awaits its final fate.
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The Magnitude of our Universe
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EARTH
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The earth
Diameter at the equator - 7,930 miles
Av distance to the Sun - 93 million miles(1AU)
Average Density - 5.52 g per cu cm
Mass (M⊕) - 5.9722 x 1024 kg
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Sun
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The Sun
• Diameter at the equator - 864,000 miles• • Average Temperature - 5,500° C
• Temperature at core - 15,000,000 ° C
• Mass - 332,900 M⊕
• Density - 1.4 g per cu cm
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Solar system
Planets and their satellites,
asteroids and other rocky objects, and an incalculable number
of comet like objects, some more than 1 trillion miles from the Sun,
make up the solar system.
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Our planet
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Our planet
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Our planet
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Our Sun with its Neighbours
There are Stars in our Galaxy more than two thousand times the diameter of Sun
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OUR GALAXYOUR GALAXY
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Our galaxy – milky way• Diameter - 100,000 Light
years• Thickness - 1,000 Light years • Stars it contains > 100,000,000,000 (100
bn)
• Mass - 1.5x1021 M⊕
(1 Light Year = 10 trillion km (1x1013 km )
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Our UniverseOur Universe
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Our universe
• Came into existence – 13.7 bn years ago
• Diameter – 46,600,000,000 (46.6 bn) light years.
• Galaxies it contains > 100,000,000,000 (100 bn)
• Stars it Contains > 100,000,000,000,000,000,000
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What universe consist of
The universe is everything that
exists, from the smallest Particles to the largest ones,
together with all matter and energy. The universe includes visible and
invisible things.
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What universe consist of
The universe, marvellous in its
majesty, is an ensemble of > 100 billion galaxies. Each
of these galaxies (which tend to be found in large groups) has 100 billion
stars. These galactic concentrations surround empty spaces, called cosmic
voids.
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Where did this Universe come from ?
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Big BangBig Bang
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Big Bang
• Time: Zero Temperature: Infinite
• Size : Infinitesimal
Though we now know about the Universe from a billionth of a second
after big bang, We do not know much about the very moment of big bang.
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Big Bang
• Time: 10-43 sec Temperature: 1032 oC
Universe's inflation begin
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Expansion
Time: 10-38 sec Temperature: 1029 oC
universe Increases in size
more than a trillion, trillion, trillion times every
fraction of a second. The expansion of the universe and the division of its forces
begin.
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Forces appearTime: 10-12 sec Temperature:
1015 oCGravity,
electromagnetic force, strong nuclear force
and weak nuclear force appear.
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Protons and Neutrons AppearTime: 10-4 sec Temperature:
1012 oCProtons and neutrons
appear, formed by threequarks apiece. Light is trapped within
the web of particles, the Universe is still dark
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Dark mater
Time: 1 sec Temperature: 1010 oC
The neutrinos separate from the initial
particle through the disintegrationof neutrons. Though having extremely
little mass, the neutrinos might be the greatest
part of the universe's dark matter
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Atom Time: 5 sec Temperature:
109 oC
The electrons and their antiparticles,
positrons, annihilate each other until thepositrons disappear. The remaining
electrons form atoms in company with proton.
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Elements FormTime: 3 sec Temperature:
107 oCThe nuclei
of the lightest elements, Hydrogen and
Thereafter Helium, form. Protons and neutrons unite to form the nuclei of
atoms
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Light Escapes
Time: 380,000 Yrs Temperature: 2700 oC
Photons (particles of light) escapes from the Dense Web of
particles and could now pass freely through the Universe.
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GRAVITATION GIVES SHAPE TO STARS
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GalaxiesTime: 500 million yrs Temp: -
243 oCGalaxies
acquire their definitiveshape. Gravitation gives shape
to islands of millions and millions of stars from masses of gases . The stars
explode as supernovas and disperse heavier elements, such as carbon.
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Solar systemTime: 9 Billion Yrs Temperature:
-258 oC
Solar system emerged. A mass of gas
and dust of supernova collapsed until it gave rise to the Sun. Later the planetary
system was formed from the leftover material.
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Solar systemTime: 9.1 Billion Yrs Temp: -
265 oC
Like the rest of the planets, the Earth
formed of material that remained After the formation of the solar system.
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Expansion Continues
Time: 13.7 Billion Yrs Temp: -270 oC
Universe continues to expand. Temperature near
big bang has cooled to 2.7 deg K
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What awaits The future of universe ?
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Future of Sun (and other stars up to 08 Solar Mass)
After five billion years Supply of hydrogen will be exhausted,
and will transform into a red giant, expanding
until it swallows Mercury. At its maximum size, it
may even envelop the Earth and condenses into a white dwarf.
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SUPER NOVASUPER NOVA
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The star swells and heats up. The
heavy core of iron explodes as SUPERNOVA and its dense core turns into a
NEUTRON STAR.
Future of other Stars ( more than 8 solar masses)
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Black hole
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When the fusion energy is unable to balance
its intense gravitational force BLACK HOLE is formed, Its gravitation
captures even light.
Future of other Stars ( more than 20 solar masses)
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Future of Stars
In the scale of hundreds of billion years
all the stars in the universe willflicker out after their nuclear fuel is
exhausted.
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Future of Matter
1032 years. Atoms disintegrate,
Protons and neutrons decay, electrons and neutrinos separate.
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Future of Universe
The big bang Theory helped solve the enigma of the
early moments of the universe. What is yet
to be resolved is the mystery surrounding its future.
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The Mystery
To unravel this mystery, the total mass
of the universe must be known, but that figure has not been reliably
determined.
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Critical Density
For the universe
to reverse expansion, An average density of more
than 10-29 gm /cm3 is required
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Open UniverseIt appears
that the mass of the universe is far too little to stop
its expansion. If this is the case, the universe's present growth is merely the
last step before its total death in complete
darkness. Universe dies as temperatures in the entire universe drops to near
absolute zero.
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Closed Universe
If the universe had more than critical
mass, it would expand until reaching a point where gravity stopped the expansion.
Big Crunch, will culminate in
an infinitely small, dense, and hot spotsimilar to the one from which the
universe was formed
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Part –IIHuman Journey in understanding Universe
since last 3000 years
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If I have seen farther than most, it is because I have stood on the shoulders of
giants.
- Isaac Newton
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At about 1000 BC people believed:
• Stars were bonfires lit by other tribes in the sky.
• Universe was a flat plate resting on the shell of a giant turtle.
• Later, Egyptians thought that the Sun was a ball of fire, and they had no idea what the fuel was.
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Understanding Universe• 640 BC Greek philosopher Thales Named as
the world’s first mathematician predicted solar eclipse accurately.
• 450 BC - The beginning of Physics Democritus said: – Nothing exists except Atoms and Empty Space, – Everything existing in the Universe is the result of
chance and necessity.• 350 BC - Greek philosopher Aristotle
– Believed earth was a sphere and not a flat plate.– Believed universe existed and would exist forever.• Philosopher Anaxagoras Thought that the Sun
was a red hot iron.
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Understanding Universe
• 300 BC Euclid Postulated laws of Geometry
• 212 .B.C.Eratosthenes Measured the circumference of earth.
• Philosopher Thales – Water is the primary and ultimate element
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Understanding Universe
• Philosopher Anaximander – There exist primary building block of matter but it can’t be water.
• Philosopher Parmenides – Matter can neither come nor pass away.
• Philosopher Empedocles – There are only few basic ingredients in the Universe, and everything is combination in a multitude of ways.
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Understanding Universe
• 2nd Century AD- Ptolemy Thought the planets orbited around Earth.
• 1514- Copernicus – Put the Sun in the centre and planets
around it.– Stars are fixed in its position, meaning a
static universe• Johannes Kepler
– That planets orbit is not circular but elliptical.– Formulated laws of planetary motion
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Understanding Universe• 1580s- Galileo Galilee.
• First to aim a telescope skyward. • Developed the formula used to calculate the
free fall of any object toward earth.• Relation between distance between distance,
time and speed.• Object under free fall, fall faster over time and
the acceleration is constant.• Free fall object irrespective of its weight
touches the ground at the same time.• Concluded that object under motion will
neither slow down or speed up but continue for ever.
Thus contradicting Aristotle’s belief that the object’s natural state is rest.
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Understanding Universe
• 1676- Ole Christensen Roemer Discovered that light travels at a finite but
very high speed.•
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Understanding Universe
• 1687- NEWTON'S EQUATION – Formulated mathematical relation for
gravitational force between masses. F = G m1x m2
r2
– Was the father of “infinitesimal calculus”
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Understanding Universe
– 1700 – Galvani Invented battery.
– 1781- Philosopher Immanuel Kant Argued that universe had a beginning.
– 1808 – John Dalton Declared that the basic unit of chemical element is atom and each chemical atom has its own weight.
– 1815- William Prout – All matters are made up of Hydrogen.
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Understanding universe
• 1800 – Scientists realised that Sun could not have stayed hot for a long time had it been a hot iron.
• 1809 - AstronomerJean Baptiste Joseph Delambre Reported the time for light to travel from the Sun to the Earth as 8 minutes and 12 seconds
• Around the same time Darwin pointed out that the earth had to be hundreds of millions year old.
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Understanding Universe
– 1820- Hans Christian Discovered a connection between electricity and magnetism.
– 1820’s –Ampere Found the mathematical relation between electricity and magnetic field.
– 1823 – Philosopher Heinrich Olbers Stars were not been shining for ever, but was
turned on in a finite past. – 1830 – Michael Faraday
• Made laws of electrolysis.• Invented electric motor.
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Understanding Universe
• .. 1867 - Dmitri Mendeleev
Created the first Periodic Table of elements.
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Understanding Universe
– 1850 – John Waterston A School teacher. Showed that chemical energy could have fuelled Sun only for some 10,000 years.
– 1853 - John Waterston Proposed that the Sun is falling under its own weight and producing heat.
– 1860 – William Thomson Calculated the Sun’s age as 100 million with the idea of shrinking Sun.
– 1860 – James Clerk Maxwell Established existence of electromagnetic waves moving through space at a finite velocity of 3 x 10 8
m/s.
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Understanding Universe
• 1865- James Clerk Maxwell Described the theories of electricity and magnetism.
• 1874 – George Johnston Stony Coined the term “Electron
• 1887-Albert Michelson Discovered that light traveled at same speed irrespective of the speed and direction of the one who measures it.
• 1887-1905- Dutch Physicist Hendrik Lorentz Attempted to explain object contracting and clocks slowing down when they move through ‘ether’ or empty space.
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Understanding Universe
– 1895 – Rontgen Accidentally discovered X-Rays.– 1986 – Henri Becquerel Discovers radioactivity.– 1896 – Marie and Pierre Curie Discovered
release of energy associated with radioactivity– 1897 – William Thomson Refined his calculation
and said Sun was 25 million years old.– 1897 – JJ Thomson Discovered that atoms have
inner structure, they contain electron.– 1897 – Earnest Rutherford Unravelled atomic
structure and radioactivity.
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Understanding Universe
– 1900- German scientist Max Plank Light and other waves energy emission is in packets called ‘quanta’ and not in any arbitrary rate.
– 1904 - Ernest Rutherford Realized that radioactivity could a source of energy for Sun.
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Understanding Universe
1905 – Albert Einstein –Explained photo electric effect–Formulated Theory of Special Relativity, with that came E=Mc2
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Understanding Universe Einstein’s Relation. 1905-1915Special Relativity Between Time-Space Time can beat at
different rates, depending on how fast one is moving. It means that the speed of light appeared same for all observers.
Relativity Principle Between Mater-energy Energy and mass are interchangeable, to be precise at E=MCE=MC22. If an object increases its mass, its energy increases, and vice versa. i.e. mater is condensed energy.
Equivalence Principle Between Acceleration-Gravity law of nature in an accelerating frame are equivalent to the laws in a gravitational field. Gravity, according to this theory, is a distortion of space that determines whether one object rolls toward another.
General Relativity Between Mater-Energy and Time-Space The presence of mater-energy determines the curvature of the space-time surrounding it. Gravity is a result of this curvature.
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Understanding Universe • 1910 – JJ Thomson Demonstrated the
existence of Electron. • 1911 – Ernest Rutherford Showed that
atoms are made-up of positive charged Nucleus around which Electrons orbit.
• 1913 – Rutherford Stated that the enormous temperatures Sun could make elements change from one to another, which mightbe stable on earth.
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Understanding Universe • 1920 – Francis Aston Found that the
atomic mass of Helium was one part in 120 less than four Hydrogen atom.
• 1920 -Satyendra Nath Bose Laid the foundation for new quantum mechanics of Schrodinger, Heisenberg.
• 1920 – Sir Arthur Erdington Stated that Sun burns Hydrogen into Helium producing heat and light.
• 1939 – Hans Bethe Explained “CNO” cycle responsible for Sun’s energy production.
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Understanding Universe • 1926- Werner Heisenberg Formulated uncertainty
principle, by which – to predict a future position and velocity of a particle, one
should be able to measure present position and velocity. – It is impossible to predict the position and velocity of a
particle in space, – More precisely one parameter is measured, less precisely
the other can be measured.
• 1930 – Wolfgang Pauli Postulated that beta decay has to be associated with emission of a particle with trifling mass.
• 1930 – Subramaniam Chandrashekar Discovered the limiting mass of the star in formation of white dwarf and neutron star.
• 1932 – James Chadwick Discovered that the nucleus contained another particle called the Neutron which has almost same mass of a proton but no electric charge.
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Understanding Universe Edwin Hubble
in 1929 observed that the universe is expanding.
Which means at some point of time earlier all matter was at one
point and its density was infinite. This discovery brought the question of the
beginning of the universe into the realm of science.
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Understanding Universe
• 1940s, George Gamow Developed the idea that the universe began with a primordial explosion.
• 1960s- Arno Penzias and Robert Wilson Accidentally detected A consequence of Big Bang in existence of uniform background radiation in space.
• 1960. Peter Higgs -predicts the existence of a new particle, the Higgs boson.
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Understanding Universe
• 1969 – Murray Gell-Mann Discovered Particle elementary than proton and neutron namely QUARK.
• 1970 – Scientists briefly contemplated if the Sun was still shining, which was quickly falsified.
• 1970-2000 – Standard model of ‘Particle Physics’ contributed by many physicsts.
• 1998 - Saul Perlmutter, Brian Schmidt, and Adam Riess discovered accelerating expansion of the Universe
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Understanding Space and Time
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Understanding Space and Time– Aristotle
•Stared that, there is a absolute Stared that, there is a absolute position in spaceposition in space..
– Newton – There is no absolute state of rest.•Stated that, it cannot be determined Stated that, it cannot be determined
if two events took place in different if two events took place in different times occurred in the same position.times occurred in the same position.
– Both Aristotle and Newton believed in absolute time.•Agreed that, one can unambiguously Agreed that, one can unambiguously
measure the interval of time between measure the interval of time between two events in space, and the time two events in space, and the time would be same whoever measures it,would be same whoever measures it, (provided they used a good clock)(provided they used a good clock)
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Understanding Space and Time
– Maxwell – Light should travel at fixed speed.
– Albert Michelson Light travels at same speed irrespective of the speed and direction of the one who measures it.
– Hendrik Lorentz Object contracts and clocks slow down when they move through ‘ether’.
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Understanding Space and Time
• Einstein– Abandoned the idea of ‘ether’ and absolute time to explain the speed of light. – It means that the speed of light appeared It means that the speed of light appeared
same for all observers.same for all observers.– The energy the object has due to motion The energy the object has due to motion
will add to its masswill add to its mass
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Understanding Space and TimeThe Consequence of Einstein’s Relativity.
– If a pulse of light is sent from one place to other.– All observers will agree on the time for the
journey.– All observers will not agree on the distance– Since speed of light is the distance travelled/time
taken. – As per relativity speed of light is same for all
observers. – So, now all observers must disagree over the
time taken. – Thus the theory of relativity put an end to
absolute time.
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I am finished with Space and Time for now
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We each exist for but a short time, and in that time explore but a small part of the whole Universe. We wonder, we seek answers living in the vast world that is by turn kind and cruel, and gazing at the immense heavens above, people have always asked multitude of questions: How can we understand the world in which we find ourselves? How does the Universe behave? What is the nature of reality? Where did all this come from? Did the Universe need a creator? Most of us do not spend most of our time worrying about these questions. But almost all of us think about them some time or other.
- Stephen Hawking
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QuoteQuote
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• Hyper Space – by Michio Kaku
• A Brief History of Time – by Stephen Hawking
• Articles on Astrophysics from Encyclopedia Wikipedia
• Illustrated Science Library – Britannica
• The God Particle - Leon M. Lederman
• The Grand Design - Stephen Hawking
• Euclid’s Widow - by Leonard Mlodinow
• The Human Touch – by Michael Frayn
• Absolutely Small - Michael D Frayer
• Public lectures and colloquium of Prof Stephen Hawking
• Zero - Cherles Seife
• Neutrino - Frank Close
•
References:
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Thanks for Listening
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