Transcript The Solar System - Tenafly Public Schools

The Solar System
Ideas About the Solar System
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Chapter 24-1
Objectives:
Compare models of the solar system.
Explain that gravity holds planets in orbits
around the sun.
Ptolemy
• In the second century
AD, the Greek
scientist Ptolemy
proposed a theory that
placed Earth at the
center of the universe.
• He also proposed that
all objects in the sky
traveled in orbits
around an unmoving
Earth.
Orbits
• He also proposed that
all the orbits were
circular.
• His model included
the Earth, the Moon,
the Sun and five
planets, mercury,
Venus, Mars, Jupiter
and Saturn.
Nicolaus Copernicus
• Between 1500 and 1530
the Polish astronomer
Copernicus developed a
new theory about the solar
system, that the Earth and
the other planets revolved
around the sun.
• He stated that each planet
took a different amount of
time to complete their
revolution in a perfect
circle.
Copernican Theory
• He also stated that the
daily movement of the
planets and stars was
caused by the Earth’s
rotation.
• This is known as the
sun centered theory.
Galileo
• Galileo Galilei gave
support to Copernicus’
theory.
• He observed that
Venus went through
phases like the moon.
This could only be
explained if Venus
were orbiting the Sun.
Modern View of the Solar
System
• As of 2006, the solar
system is made up of
eight planets and many
smaller objects that
orbit the Sun.
• The distances between
planets and the Sun
are measured in
astronomical units
(AU).
Solar System
• The Sun contains
99.86% of the mass in
the Solar System.
• The Sun’s gravity
holds the planets and
other objects in their
orbits.
The Nebular Theory
• The solar system
began as a huge cloud
of ice, dust and gas,
which later condensed
to form the sun and its
planets.
Nebular Theory of Formation
• A nearby super
massive star exploded
in a supernova.
• The shock waves from
the explosion caused
the nebula to begin to
spin in a
counterclockwise
direction. (b)
The Sun Forms First
• It began to spin faster
and the most of the
matter moved to the
middle. As it
continued to spin, it
became very hot and
when fusion began our
sun was born. (c)
Planetesimals
• As particles collide
with each other the
clump together to
form planetesimals in
the swirling disk. (c)
The Planets Form
• Because of their
greater gravitational
attraction, the larger
planetismals begin to
collect the dust and
gas. (d)
• Smaller planetismals
collide with the larger
ones and the planet
begin to form. (e)
The Asteroid Belt
Some of the matter was
not able to pull
together and formed
the pieces of the
asteroid belt.
• The matter that was
left formed moons that
began to orbit the
planets.
Inner Planets
• The planets near the
sun became so hot,
most of their gases
burned boiled away.
• The inner, hotter
planets were left as
collections of metal
and rock.
• The inner planets are
Mercury, Venus, Earth
and Mars.
The Gas Giants
• The planets farther
from the sun were less
affected by the sun’s
heat.
• They retained their
gases and grew to
enormous sizes.
• The gas giants are
Jupiter, Saturn, Uranus
and Neptune.
Motions of the Planets
• The Greeks noticed that although the stars
appeared to move across the night sky, their
position relative to each other was constant.
• The Greeks also noticed that some of the
stars appeared to wander among the other
stars.
• The Greeks called these objects, planets, or
wanderers.
Johannes Kepler
• The sixteenth-century
German
mathematician and
astronomer Johannes
Kepler discovered
something new. He
proposed that the
planets orbit in an
ellipse, or oval orbit
(egg shaped).
Orbits
Sir Isaac Newton
• Newton proposed that the
elliptical orbit is caused by
two factors: gravity and
inertia.
• Inertia causes the planet to
move in a straight line.
• Gravity pulls the planet
toward the sun.
• When the two combine,
the planet moves in an
elliptical orbit.
Period of Revolution
• A planet’s period of revolution, or time it
takes to orbit the sun, is called a year on that
planet.
• The time it takes a planet to complete one
rotation is called its period of rotation.
The Inner Planets
Chapter 24-2
• Objectives:
• To describe the main characterisitics of the
inner planets.
• To compare and contrast the inner planets
and the outer Planets.
Mercury
• Mercury was named
for the Roman god.
Mercury –Faster than a Speeding
Bullet
• Mercury moves quickly around the sun at the pace
of 48 km per second and was named after the
speedy messenger of the Roman gods.
• Mercury rotates 3 times for every 2 revolutions.
Sunrise occurs every 175 Earth-days making it
one of the hottest and coldest planets in the solar
system.
Exploration of Mercury
• Mariner 10 flew by Venus
and Mercury in 1973-1975
and sent back images.
• It photographed 45% of
the surface.
• It has many craters and
cliffs as high as 3 km.
• It has a weak magnetic
field.
Current Mission
• Messenger began a
flyby of the planet
in 2008 and an orbit
in 2011.
• It is currently
mapping Mercury.
Theory about Mercury
• Some scientists
hypothesize that
Mercury’s crust
solidified while the
iron core was still
molten and hot. A
• As the core began to
solidify, it contracted
and cliffs resulted.
Atmosphere of Mercury
• Because of
Mercury’s low
gravitational pull,
most of the gases
that could have
formed an
atmosphere have
escaped into space.
Venus – Greenhouse in the Sky
• Venus was named for
the Roman goddess of
beauty and love.
• Venus rotates east to
west, retrograde
rotation.
• Venus has a toxic
atmosphere that is
mostly carbon dioxide.
Exploration of Venus
• Astronomers believed
Venus to be the twin
of Earth until explored
by the Soviet
spacecraft Venera.
Venera landed but
stopped working after
an hour due to the
extreme temperature
and pressure.
Exploration of Venus
• Pioneer Venus Mariner 2 (1962), and
Mariner 5 (1967) which found land forms
due to once active volcanoes. Clouds are
made of sulfuric acid. The atmosphere is
very thick.
Magellan
• Between 1990 and
1994, the U.S.
Magellan prove used
radar to map the
surface.
Venus
• In early days, the sun
was cooler and Venus
may have had oceans.
(Remains of coastline
and beds can still be
detected.)
• As sun grew hotter,
the water evaporated
into the atmosphere.
Greenhouse Effect
• Clouds on Venus are so dense only a small
percentage of sunlight that strikes the top of
the clouds reaches the surface.
• Much of the heat is absorbed by carbon
dioxide in the atmosphere.
• Water vapor and later carbon dioxide in the
atmosphere created a greenhouse and made
the planet very hot (475ºC).
Earth
• The distance from
Earth to the Sun is 93
million miles or 150
million km or 1
astronomical unit.
• Unlike the other
planets, Earth has
liquid water and
supports life.
Mars
• Mars was named after
the Roman god of war
because the planet
looked bloody.
• The two moons are
Phobos and Deimos,
fear and terror.
Mars – the Rusty Planet
• Mars known as the rusty
planet because it appears
reddish. The reddish
appearance is due to the
iron oxide in the soil.
• Other features visible
from earth are the polar
caps, made of frozen
water covered by frozen
carbon dioxide.
Mars
• The temperature
difference between
day and night
produces strong
winds.
• Since the atmosphere
is so thin, Mars
temperature always
stays below 0 degrees
C.
Olympus Mons
• Mariner 9 (1971)
discovered the largest
volcano in the solar
system, Olympus
Mons. It is probably
extinct.
Discoveries on Mars
• Mariner 9 also found
long channels that
might have been
formed by flowing
water.
• Large rift valleys were
also found on the
surface.
• Valles Marineris is
shown at right.
Viking Probes
• Viking I and II landed
on Mars in 1976. Each
consisted of an orbiter
and a lander.
• They analyzed the soil
found that soil is
covered in iron oxide.
• They found no
evidence of life.
Pathfinder
• The Mars Pathfinder
carried a robot named
Sojourner to test
samples of the rocks
and soil.
• The data showed that
the iron may have
been leached out by
groundwater.
Global Surveyor
• Cameras on Global
Surveyor showed
features that looked
like sediment gullies
and deposits formed
by running water.
Odyssey and Mars Exploration
Rover
• In 2002, Mars
Odyssey began
orbiting Mars.
• It measured elements
in the crust and
searched for water.
• It detected high levels
of hematite a mineral
that forms in water
near the poles.
Odyssey and Mars Exploration
Rover
• Odyssey also relayed
information to Earth
from the Mars
Exploration Rovers
Spirit and Opportunity
in 2004.
• They confirmed that
there were once bodies
of water on the
surface.
Mars Atmosphere
• The Viking and Global Surveyor probes
analyzed gases in the atmosphere and
determined that the atmosphere is much
thinner than earth.
• It is mostly carbon dioxide with some
nitrogen and argon.
• Surface temperatures range from -125º to
35º, resulting in strong winds and dust
storms.
Seasons on Mars
• Mars axis tilt is 25º
which is close to
Earth’s. Mars goes
through seasons like
the Earth.
• The polar ice caps
change with the
season. Frozen carbon
dioxide changes to gas
in summer.
Moons on Mars
• Mars has two small
irregularly shaped
moons, Phobos
(25km) and Deimos
(13 km).
• Phobos orbits every 7
hours. Deimos orbits
every 31 hours.
Phobos and Deimos
• Deimos is the outer
moon. It is one of the
smallest moons in the
solar system. It is
smoother than Phobos.
• Phobos has many
craters such as
Stickney Crater.
Chapter 23-3
The Outer Planets
• Objectives:
• To describe the characteristics of the outer
planets.
• To describe some of the largest moons of
the Outer planets.
Solar System
Jupiter
• In 1979 Voyager 1 and
Voyager 2 flew past
Jupiter and found that it
had faint dust rings and
one moon had an active
volcano.
• Galileo arrived in 1995.
• Cassini in 2000.
• New Horizons in 2007.
Jupiter
• Our sun contains 99.7% of all the matter in
our solar system.
• Jupiter contains 70% of all the remaining
matter in the solar system.
• Romans named this planet after the king of
the Gods.
Jupiter-Almost a Star?
• The core reaches 30,000º C (5 times the
surface of the sun).
• Some scientist hypothesize that if Jupiter
had grown larger during formation, it would
have become a star.
• Jupiter gives off more heat than it receives
from the sun.
Atmosphere of Jupiter
• Jupiter is main primarily of hydrogen and
helium gases with ammonia, methane and
water.
• This atmosphere changes to a liquid
hydrogen and helium ocean near the middle
of the planet.
• Below this is what might be a rocky core.
Great Red Spot
• Continuous storms of
swirling, high pressure
gas have been detected
on Jupiter.
• The greatest of these is
called the Great Red
Spot.
Moons of Jupiter
• At least 63 moons
orbit Jupiter.
• The four largest
moons are
Gannymede, Europa,
Io and Callisto.
Io
• Both Jupiter and
Europa pull on Io
causing it be the most
• Volcanically active
moon in the solar
system.
Europa
• Europa is composed
mostly of rock with a
thick smooth crust of ice.
Under the ice might be an
ocean as thick as 50 km. If
it is water this is the only
other place in the solar
system, besides Earth,
where liquid water exists.
It has a thin oxygen
atmosphere.
Ganymede
• Ganymede has a
heavily cratered crust
of ice covered with
grooves. It has a
rocky interior
surrounding a molten
iron core. It has a thin
atmosphere.
Callisto
• Callisto is composed
mostly of rock and ice.
• It has a heavily
cratered surface , a
rock core and a thin
atmosphere of carbon
dioxide.
Galileo
• Galileo plunged into
Jupiter's crushing
atmosphere on Sept.
21, 2003. Galileo was
the first to measure
Jupiter's atmosphere.
Galileo Probe
• Galileo (found evidence of subsurface
saltwater on Europa, Ganymede and
Callisto and revealed the intensity of
volcanic activity on Io.
• New Horizons arrived at Jupiter in 2007.
Saturn
• The Voyager probes
studied Saturn inn
1980 and 1981.
Cassini reached Saturn
in 2004.
• It is the second largest
planet in the solar
system.
Saturn’s Atmosphere
• Saturn is a large
gaseous planet. It has
a thick outer
atmosphere composed
mostly of hydrogen
and helium. The
atmosphere also
contains ammonia,
methane and water
vapor.
Saturn’s Atmosphere
• The atmosphere gradually changes to liquid
as you go deeper into the atmosphere.
• Below the atmosphere and liquid layer, it
may have a small rocky core.
Saturn – A World of Many Rings
• The Voyager and
Cassini gathered
information about the
ring system. There are
several broad rings.
Saturn has seven
major rings (A-G).
• Each ring is made of
tiny ringlets made or
ice and rock particles.
Moons of Saturn
• Saturn has 47 known
moons. The largest
moon , Titan, is larger
than Mercury.
• Cassini delivered the
Hyugens probe to
study the atmosphere
of Titan and found it
composed of nitrogen,
argon and methane.
Saturn
• It is the least dense planet.
• Saturn spins so fast, it flattens at the poles
and bulges at the equator.
Uranus
Uranus – A Planet on its Side
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Uranus named for the father of Saturn,
was discovered by Sir William Herschel in
1781.
The axis of Uranus is tilted at a 98 degree
angle. Uranus has 11 thin, dark rings and
27 known moons.
Uranus’ largest moon, Titania has many
deep valleys. The valleys indicate that the
moon was reshaped by some force after
formation.
Atmosphere of Uranus
• The atmosphere of Uranus is composed of
hydrogen, helium and some methane.
• The methane gives the planet a bluish-green
color because methane absorbs the red and
yellow light while the clouds reflect the
green and blue light.
• Scientists think that under the atmosphere
of Uranus it is mainly rock and ice. There
is no separate core.
Voyager 2
• Voyager 2
studied Uranus
and found the
methane in the
atmosphere gives
it a bluish
appearance.
Neptune - the Mathematician’s
Planet
• Mathematicians
predicted the
location of Neptune
as early as 1845.
• It was discovered in
1846.
• Neptune was
named for the
Roman god of the
sea.
Characteristics of Neptune
• Neptune, like Uranus, is covered by clouds of hydrogen,
helium and methane and has a bluish appearance.
• The disappearance and reappearance of the Great Dark
Spot on Neptune in images from the Hubble show that the
atmosphere changes rapidly.
• Voyager found Neptune to have 13 moons and 5 rings.
Triton, Neptune’s largest moon, orbits in a retrograde
pattern.
• Under its atmosphere, Neptune has a mixture of rock and
ice made of methane and ammonia. It probably has a
rocky core.
Triton – a moon of Neptune
Dwarf Planets
• There are five dwarf or minor planets,
Pluto, Ceres, Eris, Makemake and
Hamauea.
Pluto – a Dwarf Planet
• When discovered, Neptune did not orbit as
predicted. Although astronomer Percival Lowell
predicted the existence of Pluto in the early
1900’s, it was not located until 1930.
• Pluto was named for the Roman god of the
underworld.
Moons of Pluto
• Pluto has three moons,
Charon, Hydra and
Nix.
Reclassification of Pluto
• A “planet” is a celestial body that (a) is in
orbit around the Sun, (b) has sufficient mass
for its self-gravity to overcome rigid body
forces so that it assumes a nearly round
shape, and (c) has cleared the
neighbourhood around its orbit.
• Pluto is considered a dwarf planet because it
does not clear the neighborhood.
Other Dwarf Planets
• Ceres is a dwarf planet with a diameter of 940
km in the asteroid belt.
• Eris, another dwarf planet, is slightly larger
than Pluto. It has a very elliptical orbit that
varies between 38 and 98 AU from the Sun. It
has one moon.
• Makemake is the third largest dwarf planet. It
orbits outside of Neptune.
• Hamuea is in the Kuiper Belt.
Other Objects in the Solar
System
Chapter 24-4
• Objectives:
• To describe the other objects that orbit the
sun, comets, asteroids and meteoroids.
• To describe how comets change as they
approach the Sun.
• To explain how objects from space
sometimes impact the Earth.
Composition of a Comet
• The core of a comet is
called the nucleus.
• The cloud of dust
surrounding the nucleus is
called the coma. Together
they form the head.
• The solar wind of the sun
blows the coma outward
into a long tail. The tail of
an incoming streams
behind, an outgoing
streams in front.
Comets
• When a comet melts, some of the rocks fall
into space and become meteoroids.
• Most of 100,000 comets in the solar system
orbit over and over.
• Halley’s comet returns every 75-79 years.
Some take thousands of years.
Oort Cloud
• The Oort cloud is a
hypothesized spherical cloud of
comets which may lie roughly
50,000 AU, or nearly a lightyear, from the Sun.[a][1]
• Sometimes the comets in the
Oort Cloud are pulled toward
the sun. As they near the sun,
they begin to melt which forms
a cloud around its core.
Comet Hale-Bopp
• Hale-Bopp was
discovered in 1995 as
it approached the sun.
It was larger than most
comets and very
bright.
Kuiper Belt
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The Kuiper belt rhyming with
"viper"),[1] is a region of the Solar
System beyond the planets extending
from the orbit of Neptune (at 30 AU) to
approximately 55 AU from the Sun.[2] It
is similar to the asteroid belt, although
it is far larger—20 times as wide and 20
to 200 times as massive.[3][4] Like the
asteroid belt, it consists mainly of small
bodies, or remnants from the Solar
System's formation. While the asteroid
belt is composed primarily of rock and
metal, the Kuiper objects are composed
largely of frozen volatiles (termed
"ices"), such as methane, ammonia and
water.
Meteoroids, Meteors and
Meteorites
• When the meteoroids fall
into our atmosphere and
rub against the gases,
friction causes it to burn,
producing a streak of light
known as a meteor or
shooting star.
• Those that strike earth are
called meteorites. They
can cause craters such as
Barringer Crater in
Arizona.
The Asteroid Belt
• Asteroids are made of rock, metal or a
combination of the two. NEAR (2000)
spacecraft went to the asteroid Eros to
collect samples.
• It is believed this matter did not form a
planet due to the strong gravitational pull of
Jupiter.
Death of Dinosaurs?
• One theory states that the collision of a
huge asteroid 65 million years resulted in
the extinction of dinosaurs and almost 90%
of all other life on Earth.
• It is believed the force of the collision was
10,000 times greater than the force of all
nuclear weapons on Earth.
The Asteroid Belt
Exploring Asteroids
• The Near Earth Asteroid Rendezvous
(NEAR) occurred in 2000 when a
spacecraft went in to orbit around the
asteroid 433 Eros and gathered data. The
data showed that Eros has many craters and
is similar to meteorites on Earth.
• The Japanese probe, Haryabusa arrived in
2005 to collect samples.