Transcript Solar Systemm

Chapter 16
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Astronomy – the scientific study of the
universe beyond Earth’s atmosphere
Universe – everything, all energy, matter, and
space
Milky Way Galaxy – one of 50 billion galaxies
scattered throughout the universe
Solar System – contains our sun and 9 planets
Sun – supplies the energy for nearly all life on
the planet earth
Intro
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The solar system - complex system of
moving masses held together by gravitational
forces
Sun is center
Sun is the dominant mass
Revolving around the sun – 8 major planets
with over 160 moons, 3 dwarf planets, and
1000’s of other objects (asteroids, comets,
meteoroids, etc.)
Section 16.1
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Terrestrial planets – Mercury, Venus, Earth,
Mars
◦ High percent of more massive (non-gaseous)
elements
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Jovian planets - Jupiter, Saturn, Uranus, and
Neptune
◦ High percent of less massive gaseous elements
Section 16.2
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The Earth is the third planet from the sun,
and is a solid, spherical, rocky body with
oceans and an atmosphere
Large amounts of surface water in all three
phases – solid, liquid, and gas – exist on
Earth
An oxygen-containing atmosphere,
temperate climate, and living organisms all
make Earth a unique planet
Section 16.3
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Atmosphere – 21% oxygen
Earth’s crust – over 90%, by volume, of the
rocks/minerals are oxygen!
We live in an oxidized environment
Examples of very common minerals at the
earth’s surface include:
◦ Quartz – SiO2, Calcite – CaCO3, Feldspar – KAlSi3O8
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Note that most common minerals have
oxygen (O) in their formula
Section 16.3
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The planet Earth is not a perfect sphere, but
rather an oblate spheriod
◦ Flattened at the poles
◦ Bulging at the equator
◦ Due to rotation about its axis
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Pole Diameter is about 43 km less than the
Equatorial Diameter
◦ Since the earth has an average diameter of 12,900
km this difference is only a small fraction
Section 16.3
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Albedo – the fraction of the incident sunlight
reflected by an object
Earth’s albedo is 33%
Moon’s albedo is 7% (from Earth the moon is
the 2nd brightest object in the night sky)
Venus’ albedo is 76% (3rd brightest is sky)
Since the Moon is so close to Earth it is
brighter than Venus
Section 16.3
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The terrestrial planets include: Mercury,
Venus, Earth, Mars
Due to physical/chemical characteristics they
resemble Earth
All four terrestrial planets are
◦ Relatively small in size and composed of rocky
material and metals
◦ Relatively close together and close to Sun
◦ Have no rings
◦ Only Earth and Mars have moons
◦ Only Earth has surface water and oxygen
Section 16.4
Section 16.4
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Mercury is the closest planet to the sun
Mercury has the shortest period of revolution
(88 days), and is the fastest moving
Mercury was named by the early Greeks after
the swift messenger of the gods
Temperatures on Mercury range from about
473oC on the side facing the sun to about 173oC on the dark side
Due to its small size and closeness to the
sun, Mercury has practically no atmosphere
Section 16.4
Rotates 3 times while circling the Sun twice
Section 16.4
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Venus is the closest planet to Earth
Venus is the third brightest object in the sky
Due to its brightness it was named after
Venus the goddess of Beauty
The surface of Venus cannot be seen from
Earth, due to dense, thick clouds that cover
the planet
Magellan radar images indicate that the
surface of Venus is composed of black, hot
rock
◦ Most surface rocks appear to be volcanic
Section 16.4
Atmosphere rotates faster than solid planet.
Retrograde rotation possibly caused by impact??
Section 16.4
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Mars has a red color, as viewed from the
Earth, and was named for the Roman god of
war
The surface of Mars has two outstanding
features that have intrigued scientists for
decades; polar ice caps and extinct volcanoes
The ice caps are composed of frozen CO2 in
the winter and CO2 vapor with frozen water in
the summer
Section 16.4
Copyright © Bobby H. Bammel. All rights reserved.
Section 16.4
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Jupiter, Saturn, Uranus, Neptune
Much larger than the terrestrial planets
Composed mainly of hydrogen and helium
◦ The four Jovian planets have a very low average
density (approximately 1.2 g/cm3)
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All four are thought to have a rocky core
composed of iron and silicates
Thick layers of frozen methane, ammonia,
and water are found above the core
Section 16.5
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Largest planet of the solar system, in both
volume and total mass
Named after the supreme Roman god of heaven
because of its brightness and giant size
Diameter is 11 times Earth’s -- 318 times more
mass than Earth
The average density of Jupiter approximately 1.3
g/cm3
Jupiter is covered with a thin layer of clouds
composed of hydrogen, helium, methane,
ammonia, and several other substances
Section 16.5
Section 16.5
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The Great Red Spot
has erratic movement,
shape, color, and size
– sometimes even
disappearing
Likely a huge
counterclockwise
“hurricane-like”
storm, lasting
hundreds of years
Section 16.5
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Distinctive system of three prominent rings
◦ Rings are inclined 27o to orbital plane
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The rings are thought to be composed of ice
and ice-coated rocks (micrometers  10 m)
Most spectacular sight that can be viewed
from Earth with a small telescope
Diameter is 9 times Earth’s -- 95 times more
mass than Earth
Average density of only 0.7 g/cm3
Section 16.5
Section 16.5
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Neptune also has a large dark spot similar to
Jupiter’s and thought to be the result of large
wind systems
Neptune and Uranus are similar in size and in
the composition of their atmospheres
In many respects these two planets can be
considered twins
Section 16.5
Section 16.5
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In 2006 the IAU adopted the following criteria
for a solar system body to be a planet:
◦ (1) It must be in orbit about the Sun.
◦ (2) It must have sufficient mass for self-gravity to
form a nearly round shape.
◦ (3) It must be the dominant body within its orbit.
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The last statement disqualifies Pluto
Section 16.6
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Pluto’s orbit takes it inside that of Neptune’s,
\ Pluto is not the dominant body of it orbit.
The IAU established two new categories for
objects that orbit the Sun.
Dwarf planets is one of the categories
Pluto, Ceres and Eris are now designated
dwarf planets
Section 16.6
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Lies in the asteroid belt between Mars and
Jupiter
Discovered in 1801 by Italian Giuseppe Piazzi
and named after the Roman goddess of
agriculture
Has a diameter of only 940 km and is the
smallest dwarf planet
Section 16.6
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Names for the god of outer darkness
Average density of only 1.65 g/cm3
Discovered in 1930, by C.W. Tombaugh
◦ Investigating discrepancies in the orbital path of
Neptune and Uranus
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Does not resemble either the terrestrial or
Jovian Planets
Pluto has not been visited by a space probe –
flyby planned in 2015.
Section 16.6
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There are similarities between Pluto and
Triton, of Neptune’s moons
Some scientists think that both are large
asteroids captured from interplanetary space
If this is the case, Pluto has maintained its
own orbital path, and Triton was captured by
Neptune
Section 16.6
Section 16.6
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Any theory that purports to explain the origin
and development of the solar system must
account for its present form
According to our best measurements, our
solar system has been in its present state for
about 4.5 billion years
A valid theory for solar system formation –
must be able to explain a number of major
properties of our solar system
Section 16.7