The document discusses the formation of the solar system, claiming it originated from a nebula approximately 4.6 billion years ago, influenced by theories such as nebular theory, encounter theory, and protoplanet theory. It describes the solar system's structure, including the sun, eight planets, moons, and other celestial bodies, categorizing planets into terrestrial and jovian types based on their composition and characteristics. Additionally, it provides specific details about each planet's features, such as their size, atmosphere, and orbital periods.

1. Origin of the Solar
System

2. Solar system
• The solar system is composed of the Sun,
the planets and their satellites, the comets,
and the asteroids.
• It is believed that the solar system has been
formed around 4.6 billion years ago, and the
evidence suggests that the members of the
solar system have a fairly uniform age.

3. Nebular Theory
• It explains that the solar system originated from a nebula
– a gas cloud made up of hydrogen particles.
• Before the nebula is stable, it is believed that a nearby
supernova resulted in the disruption of a nebula.
• This disruption created areas of high density, and as these
areas were formed, gravity acted, pulling other materials
to it. The denser the nebula became, the more heat it
produced that resulted in the formation of the Sun.

4. • At first, the Sun looked like a disc (imagine a CD), and
as it rotates, most of its mass fused in the center.
• As the Sun forms, the remaining particles that were not
sucked up by the Sun formed as rings. These rings of
particles rotated and combined to form planets.
• As it forms, the denser materials, such as iron and
nickel, sank and the less dense materials, such as
gases, floated to the atmosphere of the formed planets.

5. • The origins of the Nebula Theory can be
credited to Emmanuel Swedenborg,
Immanuel Kant, and Pierre – Simon
Laplace.

6. Encounter Theory
• It was proposed by Georges Leclerc and Comte de
Buffon which explains that the solar system formed
as a result of a near collision between a passing star
and the Sun.
• As the star passes near the Sun, the materials of both
the Sun and the star were drawn out. The interaction
from the gravity of the passing star and the Sun led
to the formation of the planets in the solar system.

7. • It is believed that the materials from the
Sun are denser. This explains the positions
of the terrestrial planets near the Sun.
• In contrast, the materials from the passing
star are less dense; thus, explaining the
positions of the Jovian planets at a distance
from the Sun.

8. Protoplanet Theory
• The Protoplanet Theory is a modified
version of the nebular hypothesis. Just like
the nebular theory, protoplanetary theorists
Carl von Weizsäcker and Gerard Kuiper
believed that the solar system started from a
nebula.

9. • An unidentified instability resulted in the pulling of dust particles
toward each other.
• This led to the formation of the “planetesimals” – objects made
up of dust and rock particles, which is believed to be the origin
of planets.
• Planetesimals combined with other planetesimals and formed
protoplanets – larger planetesimals. As the protoplanets formed,
like the Sun, they became larger as other materials condensed
with them until the fusion of hydrogen and helium happened.
• This fusion led to the production of the heat of the Sun and
resulted to the blasting off of the protoplanets made up of gases.
The smaller protoplanets were attracted by the gravity of the
larger protoplanets and made them larger until they became the
planets as we know it.

10. In summary…
The Nebular Theory explained that the Solar
System originated from a nebula that was disrupted
by a nearby supernova.
The Encounter Theory suggests that the Solar
System formed as a result of a near collision
between a passing star and the Sun.
The Protoplanet Theory is a modified version of
the nebular hypothesis stating that the Solar System
started from a nebula that was disrupted which led
to the formation of protoplanets.

11. What’s in Our Solar System?
• Our Solar System consists of a central star
(the Sun), the nine planets orbiting the sun,
moons, asteroids, comets, meteors,
interplanetary gas, dust, and all the “space”
in between them.
• The eight planets of the Solar System are
named for Greek and Roman Gods and
Goddesses.

12. The Solar System
The Solar System
• 1 star
• 9 8 planets
• 63 (major) moons
• asteroids, comets, meteoroids

13. Inner and Outer Planets
Inner and Outer Planets
• Inner Planets:
– Mercury
– Venus
– Earth
– Mars
• Outer Planets
– Jupiter
– Saturn
– Uranus
– Neptune

15. The Relative Size of the Planets in
the Solar System

16. The Sun
• The sun’s energy comes from
nuclear fusion (where hydrogen is
converted to helium) within its
core. This energy is released from
the sun in the form of heat and
light.
• Remember: Stars produce light.
Planets reflect light.
• A star’s temperature determines its
“color.” The coldest stars are red.
The hottest stars are blue.

17. The 8 Planets of the Solar System
• Planets are categorized according to
composition and size. There are two main
categories of planets:
– small rocky planets (Mercury, Venus,
Earth, and Mars)
– gas giants (Jupiter, Saturn, Uranus, and
Neptune)

18. Terrestrial Planets
Terrestrial Planets
•Mercury, Venus, Earth
and Mars
•Close to Sun
•Small masses, radii
•Rocky, solid surfaces
•High densities
•Slow rotation
•Weak magnetic field
•No rings
•Few moons
Jovian Planets
Jovian Planets
•Jupiter, Saturn,
Uranus, and Neptune
•Far from Sun
•Large masses and radii
•Gaseous surface
•Low densities
•Fast rotation
•Strong magnetic field
•Many rings
•Many moons

19. Characteristics of Small Rocky
Planets
• They are made up mostly of rock and metal.
• They are very heavy.
• They move slowly in space.
• They have no rings and few moons (if any).
• They have a diameter of less than 13,000
km.

20. Mercury
• Mercury has a revolution
period of 88 days. Mercury
has extreme temperature
fluctuations, ranging from
800F (daytime) to -270F
(nighttime).
• Even though it is the closest
planet to the sun, Scientists
believe there is ICE on
Mercury! The ice is
protected from the sun’s heat
by crater shadows.

21. Venus
• Venus is the brightest object
in the sky after the sun and
moon because its atmosphere
reflects sunlight so well.
People often mistake it for a
star.
• Its maximum surface
temperature may reach 900F.
• Venus has no moons and
takes 225 days to complete an
orbit.

22. Earth
• Earth is the only planet
known to support living
organisms.
• Earth’s surface is composed
of 71% water.
– Water is necessary for life on
Earth.
– The oceans help maintain
Earth’s stable temperatures.
• Earth has one moon and an
oxygen rich atmosphere.

23. Earth’s Moon
• It takes the moon approximately 29 days to
complete one rotation. The same side of the moon
always faces us.
• The moon’s surface is covered in dust and rocky
debris from meteor impacts. It has no water or
atmosphere.
• The moon reflects light from the sun onto the
earth’s surface.

24. • Like Earth, Mars has ice caps
at its poles.
• Mars has the largest volcano
in our solar system: Olympus
Mons. Olympus Mons is
approximately 15 miles high.
• Mars appears red because of
iron oxide, or rust, in its soil.
• Mars has two moons and
takes about two years to
complete an orbit.
Mars

25. Characteristics of Gas Giants
• They are made up mostly of gases
(primarily hydrogen & helium).
• They are very light for their size.
• They move quickly in space.
• They have rings and many moons.
• They have a diameter of less than 48,000
km

26. Jupiter
• Jupiter is the largest and
most massive planet.
• It’s diameter is 11 times
bigger than that of the
Earth’s.
• It takes about 12 years for
Jupiter to orbit the sun.
• Jupiter has 16 known
moons.

27. Saturn • Saturn is composed almost
entirely of hydrogen and
helium.
• Saturn has many rings made
of ice. Saturn’s rings are
very wide. They extend
outward to about 260,000
miles from the surface but
are less than 1 mile thick.
• Saturn has 18 known moons,
some of which orbit inside
the rings!
• It takes Saturn about 30
years to orbit the sun.

28. Uranus
• Uranus is blue in
color due to methane
gas in its atmosphere.
• Uranus has 11 dark
rings surrounding it.
• Uranus has 21 known
moons and takes 84
years to complete one
orbit.

29. Neptune
• Neptune has the fastest
winds in the solar
system: up to 2,000
km/hr.
• Neptune is also blue in
color due to methane gas
in its atmosphere.
• Neptune takes 165 years
to orbit the sun and has 8
moons.

30. OTHER SOLAR SYSTEM
OBJECTS