Araf Karsh Hamid
August 20, 2023
82

# The Universe, How it works

Concepts of Moving Objects
From Aristotle to Albert Einstein - 2000 Years of History of Physics
Relativity
Quantum Physics

The Big Bang
Inflation of Universe
Expansion of Universe & Dark Energy
Dark Matter
Composition of Universe
4% of the Universe
Evidence for Big Bang

Giants
Life of a Star – From Birth to Supernova
Black Holes
Star size Comparison
Planets in Habitable Zones

Our Home
Milky way Galaxy
From Mercury to Neptune

August 20, 2023

## Transcript

1. The Universe
How it works
Class – XI
Ebenezer International Residential School

2. 1. Concepts of Moving Objects
² From Aristotle to Albert Einstein - 2000 Years of History of Physics
² Relativity
² Quantum Physics
1. The Big Bang
² Inflation of Universe
² Expansion of Universe & Dark Energy
² Dark Matter
² Composition of Universe
² 4% of the Universe
² Evidence for Big Bang
2. Giants
² Life of a Star – From Birth to Supernova
² Black Holes
² Star size Comparison
² Planets in Habitable Zones
3. Our Home
² Milky way Galaxy
² From Mercury to Neptune
Structure of our Journey

3. ² If the empty space around an Atom is removed the entire human race can
fit into a cashew nut. That’s more than 7 billion people.
² An atom can be at two places simultaneously, in reality it’s as good as
saying you are here in Kochi as well as in New York.
² If you have a twin, then both of you can age differently, in other words at
some point in time if you are 30 years old, your twin can be 80 years 0ld.
² The Atom inside you was once part of a Dinosaur and a giant star exploded
billions of years ago.
² Time and Velocity is relative to an Observer. Measurement of velocity by
two different observers can produce two different measurements.
Science or Fiction?
Let us start our journey to discover and figure out if the above
statements are Fiction or Science! J

4. Concept of
Moving Objects
From Aristotle to Albert
Einstein
2000 Years History of Physics

5. 1. Objects at rest remained at rest unless there is a force acted upon it.
2. Objects at motion remain in motion unless a force constantly acts upon it.
3. Light is disturbance in the element Air (Wave like phenomenon), While
Democritus (the original Atomist) argued that all things in the universe
including light, are composed of indivisible sub components.
We will see how Galileo and Newton interpreted this 2nd point and How Einstein
interpreted the 3rd Point.
Aristotle (384 BC – 322 BC)

6. Galileo Galilei (1564-1642)
²Concept of Inertia
²An object in a state of motion possesses an “inertia” that causes it
to remain in that state of motion unless and external force acts on
it.
This idea became the corner stone of Newton’s Laws of motion
²Galileo’s experiments gave him the idea of friction, Ex. Pushing a
block of wood on a table – there are two opposing forces in act –
A force that is associated with push and a force associated with
friction that acts in opposite direction

7. ² Classical Relativity Example
² Train moves 100 km / hour (27.8 m / second) towards Delhi.
² Two players plays Table Tennis and hits the ball at 2m / second
² In Players reference ball moves back at forth at 2m / second
² An outside observer sees the ball as follows
² 29.8m / s when the ball is played forward (train heading in that direction –
towards Delhi)
² 25.8 m / s when the ball is played backward (in the same direction)
² Classical Relativity considers
² Time to be Absolute
² Speed of Light has to vary (like the speed of the ball according to external
observer).
Galileo Galilei (1564-1642)

8. ² Newton’s Laws of Motion
² 1st Law – Every object in a state of uniform motion tends to remain in
that state of motion unless an external force is applied to it.
² 2nd Law – The direction of Force vector is same as the direction of the
acceleration vector (F = ma)
² 3rd Law – For Every action there is an equal and opposite reaction.
² Newton’s Concepts
² Absolute Space (Static Universe)
² Absolute Time (Time is same for everyone in Universe)
² Gravity is an attractive force
² First Great Unification in Physics
Sir Isaac Newton (1642-1727)

9. ² Danish Astronomer estimated that light would take 22
minutes to travel a distance equal to the diameter of Earth’s
orbit around the Sun.
² This is equivalent 220,000 km / second about 26% lower than
the true value.
² Demonstrated in 1676 that light has a finite speed.
Ole Roemer (1644 – 1710)

10. ² No formal schooling
² His main discoveries includes
² Electromagnetic induction
² Diamagnetism
² Electrolysis
² Changing Magnetic field produces and Electric Field
² Concept on Light
² An Electro magnetic Wave

11. ² Classical Electro Magnetic Theory
² Unifies Electricity and Magnetism
² Maxwell brought Gauss’s Law, No Magnetic Monopole Law, Faraday’s
Law and Amperes Law with displacement current together with Lorentz
force to completely summarize the theoretical content of
Electrodynamics.
² Demonstrated Electric and Magnetic fields travel through space at
the constant speed of light.
² Light is an Electro Magnetic Wave
² Speed of Light / Electromagnetic Wave is Constant
² Second Great Unification in Physics
James Clerk Maxwell (1831 – 1879)

12. Albert Einstein(1879 – 1955)
² Nobel Prize in 1921 for Photoelectric effect.
² Started the Quantum Revolution as light came in discrete units of Energy
called Quanta of Light (photons).
² As per Galilean Relativity (Classical Relativity)
² Earth rotates at a velocity of v, light emitted in the direction of the Earth
rotation must be c (speed of light) + v, while light emitted in the opposite
direction would travel at c - v, relative to an outside observer.
² This fails as the speed of the light is Constant as Roemer discovered and
Maxwell calculated.
² On Electrodynamics of Moving Bodies (1905) – Special Theory of Relativity is
based on two postulates
² The laws of Physics is same in all inertial reference frames
² Speed of Light in free space is constant

13. Albert Einstein(1879 – 1955)
² Special Theory of Relativity – 1905
² An outstanding feature of SR is its mass-energy relation, expressed as E = mc2
² Unification of Space and Time by adding Time as 4th Dimension called
spacetime.
² Both Space and Time are relative rather than absolute.
² Time changes depends on the velocity and at the speed of Light Time stands
still.
² Here is a thought experiment
² If you a travel at the speed of light and hold a mirror in front of you,
What will you see?
Nothing
To see something light has to fall on the mirror and reflect back to Your eyes. As you
are traveling at the speed of light nothing can beat that speed. So, from lights
Perspective Time is ZERO and everything around is DARK!

14. Albert Einstein(1879 – 1955)
² General Theory of Relativity (1915)
² Matter causes spacetime to curve
² Gravitation is a curved field (warping of the spacetime continuum)
created by the presence of mass instead of an attractive force.
² Predictions
² Sufficiently compact mass will deform spacetime to form a Black Hole.
² This curvature of spacetime gives an effect of lensing called
Gravitational Lensing.
² Einstein's equations predicted an expanding universe!
² However, based on the notions at that time (of a static Universe) Einstein
introduced a constant called Cosmic Constant to stop the expansion of the
Universe.

15. ² 3Rd Great Unification in Physics
² Gravitational Lensing
² Light bends in the curved space
² Today Gravitational Lensing is
used detect planets, stars and
galaxies.
Albert Einstein(1879 – 1955)

16. ² Universe Goes beyond Milky way Galaxy
² Galaxies Running away – Expanding Universe (1929)
² This discovery forced Einstein to say his biggest blunder
is Cosmic Constant.
² However, wait until 1990s to see if Cosmic Constant is a blunder
or another brain wave!
Edwin Hubble (1889 – 1953)
Georges Lemaitre (1894 – 1966)
² Belgian Priest and Astronomer.
² Based on the observed data published about
expanding Universe in 1927 two years before
Edwin Hubble.

17. ² 1983 Nobel Prize awarded for his theoretical studies of the physical
processes of importance to the structure and evolution of the stars.
² 1931 He calculated, using Special Relativity, that a non rotating body
of electron degenerate matter above a certain limiting mass
(Chandrasekhar Limit 1.4 Solar masses) has no stable solutions.
² 1939 Robert Oppenheimer and others predicted that neutron stars
above 3 Solar masses would collapse into black holes for the same
reason presented by Chandrasekhar.
² These collapsed stars (Black Holes) are also known as frozen stars
because an outside observer would see the surface of the star
frozen in time.
Subramanyan Chandrasekhar (1910 – 1995)

18. The foundations of Quantum Mechanics were established during the first half
of the 20th Century by
Max Planck, Niels Bohr, Werner Heisenberg, de Broglie, A Compton, A Einstein,
Erwin Schrodinger, Max Born, John Von Neuman, Paul Dirac, Enrico Fermi,
Wolfgang Pauli, Max Von Laue, Freeman Dyson, David Hilbert, Wilhelm Wien,
Satyendra Nath Bose, Arnold Sommerfield and others.
Quantum
Physics
1927 Solvay
Conference in
Brussels

19. ² Quantum Physics is the World of Sub Atomic Particles
² Energy is not Continuous, but comes in small discrete units.
² Elementary particles behave both like particles and like waves.
² The movement of these particles is inherently random.
² Its physically impossible to know the both position and momentum of a
particle at the same time. When you one measure it precisely and other
one will be that less precise.
² The atomic World is nothing like the world we live in!
² 4th Great Unification in Physics (Electro Magnetic Force with Strong and
Weak Nuclear Force)
Quantum Physics

20. ² In 1905 in Photoelectric Effect Einstein described photon as a particle and in
Special Theory of Relativity of he considered light as a wave.
² The famous Double Slit experiment demonstrates the Duality of the particles.
² Wave particle duality postulates that all particles exhibit both wave and
particle properties.
² Copenhagen interpretation of Quantum Mechanics says that Objective reality
arises only in the act of observing or measuring. Which means the real world is
in Wave nature until we observe it!
² In other words the WORLD not there the way we think about it until we
observe it!
Wave Particle Duality

21. ² Awarded Nobel Prize in 1918 in recognition of the services he
rendered to the advancement of Physics by his discovery of energy
quanta.
² He is known as the father of Quantum Theory.
² The theory revolutionized the human understanding of Atomic and
Sub Atomic world.
² Einstein’s Relativity, Quantum Mechanics are the two greatest
pillars of 20th Century Physics. Two pillars so counter intuitive to
common sense.
Max Planck (1858 – 1947)

22. ² Danish Physicist awarded Nobel Prize in 1922 for understanding Atomic
structure and quantum mechanics.
² Copenhagen (Denmark) Interpretation of Quantum Mechanics
² All particles DON’T exists in one state or another, but in all possible states at ONCE.
² The sum total of possible states of a quantum object is called its wave function.
² The state of an Object existing in all of its possible states at once is called
superposition.
² According Bohr, when we observe a Quantum Object, we affect its behavior.
² The observation breaks an objects superposition and essentially forces the object
to choose one state from its wave function.
² This is the most widely accepted interpretation of Quantum Mechanics
² Many World Interpretation of Quantum Mechanics
² Proposed by Young Hugh Everett, He agreed with Wave function and
Superposition but disagreed with observer effect – Observing or Measuring an
Object doesn’t force it choose a specific state.
² As per him, each observation makes the universe split into two distinct universes to
accommodate each of the possible outcomes.
Niels Bohr (1885 – 1962)

23. ² Nobel Prize in 1932 for the creation of Quantum Mechanics.
² Uncertainty Principle (1927)
² Particles exhibit both particle like and wave like properties
² Wave properties of the particles collapses into particle property
when observed or measured.
² For Ex. You looked and acted like a SOLID human being when a
friend glanced at you, else you were in wave form.
Werner Heisenberg (1901 – 1976)

24. ² Awarded Nobel Prize 1933 along with Paul Dirac for the
discovery of new productive forms of atomic theory.
² In 1920s and 1930s there were two divisions of theoretical physicists who simultaneously
founded Quantum Mechanics. One for Calculus and one for Linear Algebra.
² Calculus : De Broglie, Erwin Schrodinger, Paul Dirac etc. This hand of Quantum Mechanics
became known as Wave Mechanics.
² Linear Algebra : Werner Heisenberg, Max Born, W Pauli etc.
² Schrodinger Equation is Analogous to Newton’s 2nd Law (of
motion in Classical Mechanics) in sub atomic world.
² It’s a partial differential equation that describes the quantum
state of some physical system changes within time.
² This is also known as the Wave Function
Erwin Schrodinger (1887 – 1961)

25. ² Won Nobel Prize in 1945 for the Discovery of the Exclusion Principle
also known as Pauli’s Principle involving spin theory under pinning
the structure of matter and the whole of chemistry.
²
² Pauli’s Exclusion Principle
² It says that NO two identical fermions (particles with half integer spin)
may occupy the same quantum state simultaneously.
² Four example, no two electrons in a single atom can have the same four
quantum numbers.
² Principal Quantum Number (n)
² Angular Quantum Number (l)
² Magnetic Quantum Number (ml)
² Spin Projection Quantum Number (ms)
Wolfgang Pauli (1900 – 1958)

26. ² Best known for his work on Quantum Mechanics in the early 1920s providing
the foundation for Bose – Einstein statistics and the theory of the Bose-
Einstein Condensate.
² BEC : Bose-Einstein Condensate
² It is a state of matter of a dilute gas of Bosons cooled to temperatures very near
absolute zero ( 0K or -273.15 OC).
² This state of matter was first predicted by Satyendra Nath Bose and Albert Einstein in
1924–25.
² Bose first sent a paper to Einstein on the quantum statistics of light quanta (now
called photons). Einstein was impressed, translated the paper himself from English
to German and submitted it for Bose to the Zeitschrift für Physik, which published it.
² The Class of particles that obey Bose-Einstein Statistics, Bosons was named
after him Bose by Paul Dirac.
² 4 Force Particles
² Photons (Electro Magnetic Force)
² W and Z Boson (Weak Nuclear Force)
² Gluon (Strong Nuclear Force)
² Higgs Boson (The particle which gives mass to all other particles) Discovered in
2012
Satyendra Nath Bose (1894 – 1974)

27. ² If two quantum particle (photons, electrons, molecule) are entangled
(connected) then when a measurement is made and it causes one of member
of such a pair to take on a definite value (eg. Clockwise spin), then the other
member of this entangled pair will have at any subsequent time be found to
have taken the appropriately correlated value (e.g counter clock wise).
² If two electrons or protons are entangle and the each part of this pair is in two
different Galaxies, still when you measure one of the pair in one Galaxy the
other pair will have the corresponding correlated value instantly in the other
Galaxy.
² Wait a minute – As per relativity nothing can travel faster than light. So then
how is this possible?
² The Entire universe is connected as ONE Whole thing!
Quantum Entanglement

28. Standard Model of Particle Physics
• Life
• Planets
• Stars
• Galaxies
up of an
Up & Down
Quark and
an Electron
Particle that give
Mass to other Particle
Electro
Magnetic Force
Weak Nuclear
Force
Strong Nuclear
Force

29. Fundamental Particles and
Interactions

30. That was quiet an exciting
Journey isn’t it?
Now its time we look at Big Bang

31. The Big Bang
q Over the years scientist has observed our universe and have concluded some while
back that the solar systems and galaxies..(and whatever is out there) is for some
reason moving away from each other expanding in all directions…
q This baffled many people and with due calculations and with the help of satellite's
concluded that if these objects were to retrace their paths it showed that they all
originated from a same point and SOMETHING
q Like a huge amount of force caused Them to drift away… something like an
Explosion

32. Big Bang Expansion

33. ² Developed in 1980 by Alan Guth
² According to Inflation Theory
² The Universe was created in an unstable energy state
² Which forced a Rapid Expansion of Universe at its early stage
² Theory predicts Uniform Distribution of Energy.
² What Causes Inflation(by a factor of 1078)
² Negative Pressure
² Density of Vacuum Energy
Inflation of universe

34. ² Einstein’s General Theory of Relativity Equations predicted an Expanding
Universe.
² The general notion at that time was a static universe.
² So, Einstein introduced a variable Cosmic Constant to stop the expansion and
make a static Universe.
² Dark Energy is giving a repulsive force which is resulting in the
accelerating expansion of the Universe.
² Composition of Dark Energy is a complete Mystery
² We know the it makes up around 73% of the Universe.
² As per Einstein's GR Theory (with Cosmic Constant) Empty Space contains
Energy. More the empty space more energy it contains.
² As per Quantum Theory – Empty Space is full of virtual particles that continually
form and then disappear.
Expansion of universe & Dark Energy

35. ² What we know about Dark Matter is – What it is not!
² Its not made up usual matter stuff (electrons and quarks)
² Its not Anti Matter
² Its not in the form of Clouds or Stars of Galaxies
Dark Matter

36. ² We belong to 4% of the known
² Dark Energy is responsible for the
expansion of the Universe
² 3 Scientists got Nobel Prize in 2011 for
detecting Dark Energy and Expansion
of Universe
² Dark matter’s presence is detected
using Gravitational Lensing.
Composition of the Universe

37. 4% of Universe
1. Still do we believe that we are alone in this Universe?
2. And we (Humans) are very very very very very special?

38. ² Cosmic Microwave Background Radiation
² 1978 Nobel Prize was awarded to Arno Allan
Penzias and Robert Woodrow Wilson "for their
discovery of cosmic microwave background radiation.”
² 2006 Nobel Prize was awarded to John C Mather
and George F Smoot for their discovery of the
blackbody form and anisotropy of the cosmic
² Confirmation on Expansion of Universe
² 2011 Nobel Prize awarded to Saul Perlmutter, Brian P.
Schmidt and Adam G. Riess "for the discovery of the
accelerating expansion of the Universe through
observations of distant supernovae".
Evidence for Big Bang

39. 1. Life of a Star – Birth to Supernova
2. Black Holes
3. Star Size Comparison
4. Planets in Habitable Zones
Giants

40. ² The Star Birth
² The star formation from Yellow Dwarfs to Super Giants
² The Star Death
² It explodes and there are different types of star explosions. Let us
take a look at the different Supernovas.
1. Supernova Type 1
2. Supernova Type 2
Life of a Star: From Birth to Supernova

41. Birth of a Star
² A star begins life as a cloud of dust and gas (mainly Hydrogen) known as Nebula.
² A Prostar is formed when Gravity causes the dust and gas of a nebula to clump together in
a process called Accretion.
² As Gravity keeps pulling matter inward towards its core, its temperature, pressure and
density increases.
² If the critical temperature is not reached then it ends up as a brown dwarf or a dead Star.
² If a critical temperature in the Prostar is reached then nuclear fusion begins and a Star is
born!
² A star like our Sun an Yellow Dwarf, fuelled by Nuclear fusion starts the conversion of
Hydrogen into Helium.
² Based on the Size of the Star this nuclear fusion continues creating various elements
including Iron.
² Based on the size of the Star it leads into Type 1 or Type 2 Supernova towards its end of life.
² Supernova is ultimately responsible for various elements we see in Earth and ultimately
life!

42. Star Death : Supernova Type 1 & 2

43. Super Nova Type 1a

44. ² Birth of the Black Hole rises from the death of a Star of atleast 1.44
Solar masses. A limit which is known as Chandrasekhar Limit.
² A Black Hole is a region of spacetime from which Gravity prevents
anything (including light) from escaping.
² Event Horizon is the boundary of no return, the point at which the
gravitational pull becomes so great as to make escape impossible
and for an outside observer the TIME is FROZEN at Event Horizon!
Black Holes
Supermassive Black Hole in NGC 1277
Galaxy among Biggest Discovered –
Nov 29th, 2012 Huffington Post.

45. Star Size Comparison Chart

46. Planets in Habitable Zone

47. Kepler Planets

48. Our Home / Milky way Galaxy / Solar System

49. The Milky way
q The Milky Way is where Earth and our Solar System are located.
q The Milky Way contains approximately a minimum of 100 billion stars and a maximum of 400
billion.
q Similar to other galaxies, the Milky Way contains a bulge, disk, and halo.
q The bulge in the center of the Milky Way is said to contain old stars.
q The halo of the Milky Way is believed is said to contain dark matter and globular clusters.
q The disk is said to be made of young stars, dust, and gas.
q The Milky Way is known as a binary system.
q Other Dwarf Galaxies orbit the Milky Way.

50. ~*~*~The Solar system~*~*~
q The solar system includes the Sun and all the objects that orbit around it due to its gravity. This
includes things such as planets, comets, asteroids, meteoroids and moons.
q There are eight planets in the Solar System. The four inner planets
are Mercury, Venus, Earth and Mars while the four outer planets
are Jupiter, Saturn, Uranus and Neptune.
q The Solar System formed around 4.6 billion years ago.
q The inner planets (also known as terrestrial planets) are smaller and made mostly of rock and
metal.
q The outer planets (also known as gas giants) are much larger and made mostly of hydrogen,
helium and other gases.
q As of 2008, there are also five dwarf planets: Pluto, Ceres, Eris, Makemake & Haumea.
q There is an asteroid belt which lies between the orbits or Mars and Jupiter, it features a large
number of irregular shaped asteroids. These asteroids are actually pieces of a planet that has
been destroyed or a planet that was not created and formed properly like mars mercury Venus
and earth.

51. • Mercury is the planet nearest to the sun. It has a
diameter of 3,031 miles, about two-fifths the
Earth's diameter. Because of Mercury's size and
nearness to the brightly shining sun, the planet is
often hard to see from Earth without a telescope.
• The ancient Romans named it Mercury in honor
of the swift messenger of their Gods.
• Mercury has no moons.
The sun appears 2 and a half times larger in
Mercury's sky compared to the Earth's.
• If you weigh 100 pounds on Earth, you would only
weigh 37 pounds on Mercury.
• Mercury has virtually no atmosphere. It however
has small traces of an atmosphere which consists
minute quantities of Hydrogen, Oxygen, Sodium,
Potassium and argon.
• Because of the lack of atmosphere, Mercury's sky
is black and the stars probably can be seen during
the day.
• It takes less than 88 Earth days for Mercury to
orbit around the sun.
Mercury

52. • Venus is the second planet from the sun and the
closest planet to Earth.
• It is named after The Roman Goddess of love and
beauty, but it's extremely hot and deadly
atmosphere makes it impossible for any human
astronaut to explore it's surface.
• The diameter of Venus is about 7,520 miles which
is about 400 miles smaller than that of Earth.
• Venus is known as Earths' twin sister because of
its similar size and proximity to each other.
• Its atmosphere is made up mostly of carbon
dioxide.
• Venus rotates so slowly that it orbits the sun
faster than it can make one whole rotation on its
axis. In other words, Venus has a longer day than
year.
• It takes 243 days for Venus to make a rotation.
• And it takes 224 days for Venus to orbit around
the sun.
Venus

53. • Earth is a very special planet.. The reason why is
that, well obviously it supports life
• But what makes this so called life supporter is
because it’s in the some where in this region
called the circumstellar habitual zone
( "ecosphere", "Liquid Water Belt", "HZ", "life
zone" or "Goldilocks zone") is the region around
a star where a planet with sufficient atmospheric
pressure can maintain liquid water on its surface..
• This zone or area that our earth is in is perfect in
the sense that earth is not very close to the sun
making it too hot.. And neither is it farther away
making it too cold.
And because it’s in this zone which is PERFECT
neither too hot nor too cold.
It supports life as it can maintain water on it’s
surface..
• Surprisingly there are atleast 500 million planets
like earth in our milky way..
Who knows there might be other life out there
• And for those who don’t think life exist outside
you might as well take a cup of ocean water look
at it and say there is no whales in the ocean..
Earth

54. • Mars is the only planet whose surface can be
seen in detail from the Earth.
• It is reddish in color, and was named after the
bloody red God of war of the ancient Romans.
• Mars is the fourth closest planet to the sun
• Mars is red because it is rusty. There is a lot of
iron in the soil, and the air on Mars has made it
turn red-just like rusty iron on Earth.
• One of Mars' moons, Phobos, is moving closer
and closer to Mars. Scientists think that one day
it will crash into Mars.
• Mars has the tallest Volcano in the Solar System
named Olympus Mons and it is 15 miles high
which is three times the height of Mount
Everest.
• Like Earth, the poles of Mars are covered in ice.
The ice becomes thicker in the winter.
• Mars orbits the sun every 687 Earth days.
Mars

55. • Jupiter is the largest planet in our Solar System.
Ancient Astronomers named Jupiter after the king
of the Roman Gods. Jupiter is the 5th closest
planet to our sun.
• If you weigh 100 pounds on Earth, you would
weigh 264 pounds on Jupiter.
• Jupiter has a mass 318 times greater than the
Earth's and a diameter that is 11 times larger.
• The mass of Jupiter is 70% of the total mass of all
the other planets in our Solar System.
• Jupiter's volume is large enough to contain 1,300
planets the size of Earth.
• Jupiter rotates faster than any planet in the Solar
System.
• It rotates so quickly that the days are only 10 hours
long...
• But it takes 12 Earth years for Jupiter to complete
an orbit around the sun.
Jupiter

56. • Saturn is the second largest planet. Only Jupiter
is larger.
• Saturn has seven thin, flat rings around it.
• A couple of planets have rings, but their rings
are much fainter than those around Saturn
• Saturn has the lowest density of all the planets
in the solar system. It is so light that it could
actually float on water if there was an ocean big
enough to hold it.
• It takes about 29.46 Earth years for Saturn to
orbit around our sun.
• Saturn's rings are made up of billions of pieces
of rocks and dust.
• Saturn has over 30 known Satellites, but many
of them are small and faint.
• Saturn has no solid surface. It is a giant ball of
gas, but it does have a solid inner core.
• The temperature difference between the poles
and the equator is very small on Saturn.
Saturn

57. • Uranus is the seventh planet from the sun and is
named after the Greek God of the sky in latin.
• Because of the strange way it spins, nights on some
parts of Uranus can last for more than 40 years.
• The planet's most extraordinary feature is the tilt of
its rotational axis, which is almost perpendicular to
the plane of the eclipitc, which means that it
alternately has its north pole and its south pole
turned towards the sun.
• Uranus has 27 known satellites.
• In many Asian languages, Uranus' name is translated
into “Sky king star”.
• Uranus mass is more than 14 times larger than Earth.
• Uranus and Neptune are both known as Ice Giants.
Uranus

58. • After Pluto was declassified as a planet, Neptune
became the farthest planet from the sun.

• Neptune is so far away that it took the space
probe Voyager 2, 12 years to reach it.
• Neptune is the stormiest planet. The winds there
can blow up to 1,240 miles per hour, that is three
times as fast as Earth's Hurricanes.
• The planet has a system of thin dark rings but they
are incomplete rings and are best described as
arcs.
• Neptune is a sea blue color due to the methane
gas in its atmosphere.
• Neptune once had a great dark spot similar to
Jupiter.
• Neptune only receives 1/900 of the solar energy
that reaches Earth.
• Neptune has its own heat source, it emits a
quantity of energy 2.7 times greater than it