Transcript Earth

The Solar System
SOL 6.8
Introduction
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In this presentation we will :
explore the nine planets and their
features.
compare and contrast the similarities
and differences of the “inner” and
“outer” planets.
examine the location of the solar system in
the universe and explore theories about its
beginning.
take a detailed look at comets, asteroids, and
moons as significant members of our solar system.
Let’s start with the Sun
A G2 typical yellow dwarf star
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Diameter: 1.4 million kilometers
Contains 99.8% of the mass of the
solar system
The volume of the Sun could hold
1 million Earths.
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Composition: 75% hydrogen,
25% helium
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Surface Temperature: 5500 oC
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Rotates on its own axis once
every 25.4 days at the equator.
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Core Temperature: 15 million
degrees Celsius
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Revolves around the center of the
Milky Way Galaxy once every 225
million years.
How about the planets?
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The solar system is divided into two basic
groups. The inner and outer planets.
The inner planets lie inside of the asteroid belt
and consist of Mercury, Venus, Earth, and Mars.
They are four of the five smallest planets in the
solar system and are often called terrestrial
planets because of their similarities with Earth.
They have high densities because of heavy
metal cores.
Lets take a closer look at each one.
Mercury
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Mercury is the eighth largest
planet (or second smallest) in the
Solar System.
Mercury is a heavily cratered
planet, composed of rock with a
central iron core that is threequarters of the diameter of the
planet (3,600 km). Following the
Earth, Mercury is the second
densest planet in the Solar
System.
Covered with thousands of
craters, the surface of Mercury
closely resembles the Earth's
Moon.
Mercury has few non-cratered
areas on the surface, with the
exception of the large flat area
known as the Caloris Basin, and a
few other small areas.
The Caloris Basin, the result of an
asteroid impact, is 1300 km in
diameter.
More on Mercury
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The surface temperature of Mercury is
characterized by major fluctuations.
The daytime side of the planet reaches
over 400 degrees C (752 degrees F),
but on the night side the temperature
falls to -170 degrees C (-274 degrees
F).
Mercury has no atmosphere and no
known satellites.
The only visit to Mercury was made by
the Mariner 10 spacecraft in 1974.
Mercury was believed by the Greeks
to be two different stars. Mercury's
appearance in the morning was called
Apollo, and its evening appearance
was referred to as Hermes.
Mercury, often identified with the
Greek god, Hermes, is the messenger
of the gods in Roman mythology.
Mercury is often characterized with
winged sandals.
Position:
Closest to Sun
Distance from Sun:
57,910,000 km
Mercury Day:
58.65 Earth Days
Mercury Year:
87.97 Earth Days
Orbital Speed:
47.8 km/sec
Eccentricity of Orbit: 0.206
Satellites:
None
Diameter:
4,878 km
Mass:
3.30e23 kg
How About Venus
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Venus is the sixth largest planet in the
Solar System.
Similar in size, density, and mass,
Venus and Earth often referred to as
sister planets. However the surface
and atmosphere of the two planets are
drastically different.
The atmosphere of Venus is primarily
composed of carbon dioxide (96%)
and nitrogen (3%), with traces of other
gases and little to no water vapor.
Venus would have a cold climate if it
weren't for the high concentration of
carbon dioxide in its atmosphere
(96%).
The high albedo on Venus reflects the
majority of the solar radiation that
reaches it, but carbon dioxide, a well
known greenhouse gas, keeps the
planet extremely warm.
In fact the surface temperature of
Venus is over 480 degrees C (900
degrees F).
Photograph of Venus
More about Venus
Magellan Probe Computer Generated
Surface Image
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The clouds in Venus' atmosphere are
composed of sulfuric acid which
causes the planet to reflect 65% of the
sunlight that reaches it.
Thus, Venus the third brightest object
in the sky (third only to the Sun and
the Moon).
The atmospheric pressure on the
surface of Venus is 90 times the
pressure on Earth..
The surface of Venus is very dry with
flat plains, highland regions, and
depressions.
The interior of Venus is composed of a
central iron core and a molten rocky
mantle, similar to the composition of
Earth.
The rotation of Venus is very slow. A
day on Venus (243 Earth days) is
longer than a year (224.7 Earth days).
The rotation is also opposite from that
of Earth, with the Sun rising in the
West.
The Russians photographed the
surface first with their Venera probe
And a little more Venutian info…
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Venus has been visited
by over 20 spacecrafts.
The first visit was
made by Mariner 2 in
1962.
The Soviet Venera 7,
which visited Venus in
1970, was the first
spacecraft to land on
another planet.
A recent visit made by
the Magellan, launched
in 1989, produced high
resolution maps of the
surface using radar.
Venus is named after
the Roman goddess of
love and beauty.
Position:
Second from Sun
Distance from Sun:
108,200,000 km (.72 AU)
Venus Day:
243 Earth Days
Venus Year:
224.7 Earth Days
Orbital Speed:
35 km/sec
Eccentricity of Orbit:
0.007
Satellites:
None
Diameter:
12,100 km
Mass:
4.869e24 kg
Major Atmospheric Gas: Carbon Dioxide
The Third Planet - Earth
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Diameter: 12.7 thousand
kilometers
Mass: 6.0 x 1024 kilograms or
six sextillion metric tons
Composition: water, silicon,
carbon, heavy metal ironnickel core
Atmosphere: nitrogen, water
vapor, oxygen, carbon dioxide
Surface Temperature: -13 –
37oC
Called the “Blue Planet”
because of the color of
nitrogen in it’s atmosphere.
More on the Earth
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The Earth rotates on an axis that is tilted 23 ½ degrees relative to
the orbital or ecliptic plane.
It’s period of rotation is one day or 23 hours and 56 minutes.
The period of revolution around the Sun is a year or 365 and onequarter days.
Earth (continued)
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Earth is the fifth largest planet in
the Solar System.
The Earth is around 4.6 billion
years old.
Earth is the only presently known
planet in the Solar System to
support life. The earliest fossil
evidence for life dates back 3.5
billion years ago.
71% of Earth's surface is covered
in water.
The Earth is the densest planet in
the Solar System.
The Earth travels at an orbital
speed of 108,000 km (67,000
miles) an hour.
The Earth has only one satellite,
the Moon. The Moon is the
second brightest object in the sky.
Position
Third from the Sun
Distance from Sun:
149,600,000 km
Earth Day:
24 hours
Earth Year:
365 Earth Days
Orbital Speed:
29.8 km/sec
Eccentricity of Orbit:
0.017
Satellites:
1
Diameter:
12,756 km
Mass:
5.976e24 kg
Major Atmospheric Gas: Nitrogen
How about the Red Planet - Mars
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Mars is the seventh largest planet
in the Solar System.
Known as the Red Planet, Mars
is characterized by its red, dusty
landscape.
In observation of Mars seasonal
changes and river channels on
the surface, many scientists
hoped for a possibility of Martian
life. They speculated that the
composition of Mars' was similar
enough to Earth to support life.
However, the atmosphere on
Mars is very different than
Earth's, with only small amounts
of life supporting oxygen and
water.
The atmosphere on Mars is very
thin, composed mainly of carbon
dioxide(95%), nitrogen(2.7%),
and argon(1.6%), with traces of
oxygen and water.
More on Mars
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Mars has polar ice caps,
composed of solid carbon dioxide,
that advance and retreat with the
changing seasons.
Temperatures on Mars vary from a
maximum of 0 degrees C (32
degrees F) to minimum -100
degrees C (-148 degrees F).
The terrain on Mars is complex
and varied, with deep canyons,
mountains, volcanoes, and
craters. Olympus Mons, the
largest mountain in the Solar
System, stands on Mars with an
altitude of 24 km (78,000 feet) with
a base that is 600 km across.
Valles Marineris is a system of
canyons that stretch out over the
surface of Mars for nearly 2,500
miles (4000 km). The canyons can
get up to 200 km wide and 6 km
deep in some areas.
Position:
Fourth from Sun
Distance from Sun:
227,940,000 km
Mars Day:
24.6 Earth Hours
Mars Year:
686.98 Earth Days
Orbital Speed:
24.2 km/sec
Eccentricity of Orbit:
0.093
Satellites:
Two
Diameter:
6,794 km
Mass:
6.4219e23 kg
Major Atmospheric Gas: Carbon Dioxide
Mars (continued)
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Mars was first visited by
the Mariner 4, in 1965,
which transmitted 22
pictures of the Martian
surface back to Earth.
The pictures revealed
that there was no water
or life on the cold
surface, shattering hopes
to find life on Mars. There
has been no proof to date
that there was ever life
on Mars.
Mars has two small
satellites named Phobos
and Deimos.
Mars is the god of war in
Roman mythology.
Mars Rover currently on Mars
What have you learned?
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Name the inner planets.
Which one is smallest?
Which one is biggest?
Which ones have water?
Which is the densest?
Which one is the “red
planet?
Which have no moons?
Which one has two
moons?
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Which has no
atmosphere?
Which has an
atmosphere of sulfuric
acid?
Which is the brightest
object in the night sky
after the Sun and Moon?
Which has one moon?
Which has the tallest
mountain?
The Outer Planets
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The outer planets consist of four gas
giants, Jupiter, Saturn, Uranus, and
Neptune, and the outermost planet called
Pluto.
Another 1-2 AUs and we’ll be in the
Asteroid Belt
Asteroids are small rocky objects that
move in elliptical orbits in the asteroid belt
between the orbits of Mars and Jupiter.
 Their average distance from the Sun is
about 2.9 astronomical units (A.U.)
 Asteroids are also called minor planets.
Giuseppe Piazzi discovered the first
asteroid, Ceres, on January 1, 1801.
 Take a look.
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Ten thousand
of these??
More on Asteroids
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Asteroids range in size from Ceres, which has a
diameter of about 1000 km, down to the size of
pebbles.
Sixteen asteroids have a diameter of 240 km or
greater. They have been found inside Earth's
orbit to beyond Saturn's orbit.
Most, however, are contained within a main belt
that exists between the orbits of Mars and
Jupiter.
Astronomers have calculated that, the chances
of a collision between Earth and an asteroid
averages out to only one collision about every
300,000 years.
On to Jupiter
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Jupiter, the largest
planet in our solar
system, is 318
times larger than
Earth.
It has 62 moons.
The largest four
were discovered by
Galilei Galileo. Io,
Europa, Ganymede
and Callisto
Jupiter is the fourth
brightest object to
be seen in the sky.
Occasionally Mars
will appear to be
brighter than Jupiter
in the Earth's sky.
The Great
Red Spot
More on Jupiter
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Jupiter spins faster on its axis than
any other planet in our solar system.
One day on Jupiter is 9.8 Earth hours
Position:
Fifth from Sun
Distance from Sun:
778,330,000 km
Jupiter is a gas planet, composed
largely of hydrogen (89%) and helium
(11%), with traces of methane, water
vapor, and ammonia. The gas gets
denser with depth turning into liquid
toward the center. The tops of the gas
clouds in the atmosphere make up
the colorful texture on Jupiter.
Jupiter Day:
9.8 Earth Hours
Jupiter Year:
11.9 Earth Years
Orbital Speed:
13.1 km/sec
Eccentricity of Orbit:
0.0483
Satellites:
16 (plus Rings)
Equatorial Diameter:
142,984 km
Polar Diameter:
133,708 km
Mass:
1.900e27 kg
The Great Red Spot is a high
pressure region with clouds, moving
in a counter-clockwise direction,
thought to contain red phosphorus.
The cloud tops in the Spot are higher
than the surrounding clouds. The
Great Red Spot is about 12,000 by
25,000 km.
Major Atmospheric Gas: Hydrogen
Still More About Jupiter
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The Pioneer 10 was the first spacecraft to visit
Jupiter in 1973, and was followed by visits from
Pioneer 11, Voyager 1, Voyager 2, and Ulysses.
The Galileo probe arrived in the Jovian system
in late 1995 and will remain in orbit there until
1997 (two years).
Jupiter, sometimes called Jove, was the King of
the gods in Roman mythology and the son of
Saturn.
Like Saturn, Jupiter has rings, though they are
much smaller, fainter, and darker. Jupiter's rings
were discovered by the Voyager 1 in 1979.
Take a look!
Rings of Jupiter??
How about Saturn
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Saturn is the sixth planet from
the Sun and the second largest.
Saturn is flattened at the poles,
due to a fast rotation on its axis.
Galileo discovered Saturn in
1610, and was confused by its
strange appearance in his
telescope.
Saturn is a gas planet, like
Jupiter, and is large enough
and far enough away from the
Sun to retain its original
primitive gases. The
atmosphere on Saturn is
primarily composed of
hydrogen, with small amounts
of helium and methane.
More about Saturn
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Saturn is the only planet in our
solar system that is less dense
that water.
Saturn is well known for it's
beautiful ring system, which are
composed of millions of
particles and large chunks of ice
and snow. The ring system is
divided into various parts,
including rings and gaps. The
bright A and B rings are
separated by a large gap called
the Cassini Division. Radial
"spokes" composed of fine
particles, about the size of dust
specks, were found in the BRing by the Voyager.
Saturn was the god of
agriculture in Roman mythology.
Saturn is also the father of
Jupiter, the king of the Roman
gods.
Position:
Sixth from Sun
Distance from Sun:
1,427 million km
Saturn Day:
10 hours, 14 minutes
Saturn Year:
29.5 Earth Years
Orbital Speed:
9.7 km/sec
Eccentricity of Orbit:
0.056
Satellites:
18 (plus rings)
Equatorial Diameter:
120,536 km
Polar Diameter:
108,728 km
Mass:
5.688e26 kg
Major Atmospheric Gas: Hydrogen
Mission to Saturn
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This photo was
taken by the
CassiniHuygens
Probe on a
mission to
Saturn and its
largest moon,
Titan.
The Cassini-Huygens Probe
on route to Saturn
How About Uranus?
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The atmosphere of Uranus
is composed of hydrogen,
helium, and methane. The
methane in the atmosphere
absorbs red light, giving the
planet a blue-green color.
Uranus is considered
unusual because the planet
is tipped on its side.
The poles actually point
towards the Sun. This is due
to the fact that its magnetic
field is tilted 60 degrees
from the axis of rotation.
Like Venus, Uranus spins
from east to west, which is
opposite from the spin of
Earth.
More About Uranus
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Uranus has rings that are
composed of fine dust, rocks,
and ice boulders. The rings are
very faint and remained
undiscovered until the Voyager
2 spacecraft visited the planet
in 1986.
Voyager 2 is the only
spacecraft to have visited
Uranus.
Uranus is named after the
Greek god of the sky. Uranus
was the husband of Gaia, the
goddess of the Earth.
Take a look at the rings of
Uranus.
Position:
Seventh from Sun
Distance from Sun:
2,870,990,000 km
Uranus Day:
.72 Earth Days
Uranus Year:
84.01 Earth Years
Orbital Speed:
6.6 km/sec
Eccentricity of Orbit:
0.047
Satellites:
15 (plus rings)
Diameter:
51,800 km
Mass:
8.686e25 kg
Major Atmospheric Gas: Hydrogen
Nine rings…Can you Count them?
Now on to Neptune
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Neptune is the fourth
largest planet in the
Solar System.
The only spacecraft ever
to visit Neptune was the
Voyager 2 in 1989.
Neptune is a gas planet,
composed of hydrogen,
helium, methane, with
traces of ammonia and
water.
The blue color of the
planet is due to the
absorption of red light by
methane in the
atmosphere.
More about Neptune
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Neptune has actually been the
most distant planet from the sun
since 1979 to 1999, due the fact
that Pluto's orbit is highly
eccentric. Pluto is now the most
distant planet from Sun the
again.
Neptune has the stronger winds
than any other planet in the
Solar System. Blowing in a
westerly direction, winds on
Neptune get up to 2,000 km/hour
(1,200 miles/hour).
"The Scooter" is a cloud that
moves around Neptune about
every 16 hours.
Neptune is the god of the sea in
Roman Mythology.
Position:
Eighth from Sun
Distance from
Sun:
30.06 AU
Neptune Day:
0.75 Earth Days
Neptune Year:
164.83 Earth Years
Orbital Speed:
5.4 km/sec
Eccentricity of
Orbit:
0.0097
Satellites:
8 (plus rings)
Diameter:
49,528 km
Mass:
1.0247e26 kg
Major
Hydrogen
Atmospheric Gas:
Can you see the faint rings of
Neptune?
On to Pluto
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Pluto is the smallest
planet in our Solar
System.
Not a very good
picture..huh?
It’s just too far away.
Pluto is named after
the Greek lord of the
underworld, Hades. It's
only satellite, Charon,
is named after the
boatman who ferried
the dead across the
River Styx to Hades.
More on Pluto
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Pluto's moon, Charon, is
12,200 miles from the
planet and has a
diameter of 1,200 km
(740 miles).
Charon was first seen
from Earth in 1978.
Pluto and Charon are
similar in size, and they
orbit each other like a
double planet, with the
same sides permanently
facing each other.
Check this out.
Position:
Ninth from Sun
Distance from Sun:
39.5 AU
Plutonian Day:
6.39 Earth Days
Plutonian Year:
247.7 Earth Years
Orbital Speed:
4.74 km/sec
Eccentricity of
Orbit:
0.2482
Satellites:
1
Diameter:
2340 km
Mass:
1.32e22 kg
Major Atmospheric
Gas:
Methane
Pluto and Charon
Planetary Moons (9/2003)
Planet
Number of Moons
Mercury
0
Venus
0
Earth
1
Mars
2
Jupiter
62 WOW!
Saturn
31
Uranus
27
Neptune
13
Pluto
1
How about Comets
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Comets are small, fragile, irregularly shaped bodies composed of a
mixture of non-volatile grains and frozen gases.
They are thought to come from places in the Solar system called the
Kuiper belt, and the Oort Cloud.
The Kuiper Belt is a disk-shaped region past the orbit of Neptune
extending roughly from 30 to 50 AU from the Sun containing many
small icy bodies. It is now considered to be the source of the shortperiod comets.
Occasionally the orbit of a Kuiper Belt object will be disturbed by the
interactions of the giant planets in such a way as to cause the object
to cross the orbit of Neptune or cross into the inner solar system.
The statistics imply that the Oort cloud may contain as many as a
trillion (1e12) comets. Unfortunately, since the individual comets are
so small and at such large distances, we have no direct evidence
about the Oort Cloud.
The Anatomy of a Comet
Space Missions to Comets
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Deep Space 1: NASA. Launched in 1998. DEEP
SPACE 1 flew within 10 miles (16 kilometers) of
Asteroid 1992 KD Braille on July 28, 1999. The
mission is mainly a test of new propulsion and
navigation technology. The extended mission
was to include flybys of two comets, WilsonHarrington and Borrelly, but a problem with the
tracking system meant that priority is now being
given to Comet Borrelly.
Stardust: NASA. Launched 1999. STARDUST
will fly past comet Wild 2 and capture dust grains
blown from the comet's surface. These will be
returned to Earth for analysis.