Transcript Largest moon in the solar system

Modeling the Solar System
Geocentric Model aka Ptolemaic Model
Ancient Greeks
 Earth is at the center of the Universe.
 The Earth stood still & never moved.
 Stars are on a separate sphere orbiting the
Earth
was named after the philosopher Claudius Ptolemy
who lived circa 90 to 168 A.D.
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7 objects moved differently in the sky known as
the “wanderers” or planetai. Sun, Moon, Mercury,
Venus, Mars, Jupiter & Saturn
Ptolemy
 Designed an updated model of the
geocentric model.
 The planets orbit in circles around the
Earth & also travel in circles on the orbit.
Heliocentric Model
Nicholas Copernicus
 Earth revolves around the Sun.
 Moon revolves around the Earth.
 Earth rotates on an axis.
 Planets revolved around the Sun.
 Planets have circular orbits.
Tycho Brahe died of a ruptured bladder because he refused to excuse himself at a banquet as
it would have been rude.
Tycho had his nose cut off in a duel. He
wore a gold and silver prosthetic nose
Tycho Brahe & Johannes Kepler
 Brahe charted the motions of celestial
bodies before telescopes.
 Mathematician Kepler used Brahe’s
data to form the Laws of Planetary
Motion:
1. The path of a planet around the Sun
is an ellipse.
2. A planet will travel faster
when it is closer to the Sun &
cover a greater distance than
when it is farther away.
3. The more distant the
planet’s orbit is from the
Sun, the longer it takes to
make a single revolution.
Revolutionary Periods
Mercury = 88 Earth days
Earth = 365.25 days
Jupiter = 11.86 Earth years
Pluto = 248 Earth years
Nebula Theory: Formation of the Solar System
1. More than 4.6 billion years ago, the solar system
was a cloud (nebula) fragment of gas, ice, & dust.
2. Gradually, this cloud fragment contracted into a
large, tightly packed, spinning disk. The disk’s
center was so hot & dense that nuclear fusion
reaction occur forming the Sun.
3. The rest of the material in the disk cools
enough to clump into scattered solids.
It is estimated that within the entire Universe there are
more than a trillion galaxies (the Milky Way itself
contains 100 billion stars). This means that there are
probably about 100 (to the 22nd power) stars in the
entire cosmos.
Our sun is a second or possibly 3rd generation star
A new star is born in our galaxy every
18 days
Scientists believe that we can
only see about 5% of the matter in
the Universe. The rest is made up
of invisible matter (called Dark
Matter) and a mysterious form of
energy known as Dark Energy.
4. Finally, these clumps collided & combined to
become the planets, dwarf planets, comets,
asteroids, etc.
» The planets all orbit on the same plane called
the ecliptic.
» The 8 planets occasionally line up in a straight
line.
Astronomers have discovered more than 150 planets outside our solar
system, ranging from 100 to 1,000 times Earth's mass.
Gravity and the Solar System
Galileo
Believed that objects fall to the Earth at
the same rate despite the object’s
weight.
 Air resistance slows down falling
objects.
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Sir Isaac Newton
 Law of Universal Gravitation
» Gravity is a force
generated between two
objects.
» Gravity depends on the
mass of each object &
the distance between
them.
Gravity Equation
F = G
m 1 x m2
r2
F is gravitational force
r is the distance between the 2 masses
m is the mass of an object
G is the Gravitational Constant
G= 6.673 x 10 -11
m1
r
m2
Albert Einstein
 Theory of General Relativity
» Matter tells space how to curve.
» Curved space tells matter how to move.
» Everything moves in the straightest possible line in
curved space-time.
The Planets & their Moons
Distances in the Solar System
 Astronomical Units
Distances in space are millions of
miles/kilometers in the solar system.
 One astronomical units (AU) is the
distance between the Earth & the Sun.
1 AU = 93 million miles = 150 million km
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Terrestrial Planets
Mercury
 .39 AU from the Sun
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Named after the Roman messenger god
(Hermes)
Covered in craters & cliffs, similar to the
Moon.
No true atmosphere; trace amounts of
sodium & potassium.
As cold as -170oC in the dark & as hot as
425oC in the light.
Mercury is the most iron rich planet in the Solar
System with an iron core like Earth.
Earth and moon from Messenger (on it’s way to
Mercury)
The sun's rays are about seven times as strong on Mercury as
they are on the Earth.
Venus
 .72 AU from the Sun
Its atmosphere is made up mostly of
 Named after the Roman
carbon dioxide. It has clouds made of
sulfuric acid!
goddess of love & beauty
(Aphrodite)
 Thick atmosphere of CO2
which causes a severe
greenhouse effect
producing temperatures well
over 400oC. (Hottest planet)
 Air pressure is 90 times
greater than the Earth’s.
 Similar to Earth’s size.
Venus is known as Earths' twin sister because of
its similar size and proximity to each other.
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Has retrograde rotation (rotates backwards)
Takes longer to rotate than to revolve around the
Sun. (Day is longer than its year.)
Covered with inactive volcanoes.
3rd brightest object in Earth’s sky.
The pressure at the
centre of the Earth is
27,000 tons per square
inch.
The Sun is 330,330 times larger
than Earth.
Earth
 1.0 AU from the Sun
 Also known as Gaia, Terra,
or Home.
 More than 70% of Earth’s
surface is covered in water.
 Only planet known to have
life in existence.
 Has a natural satellite
(Moon/Luna.)
Earth spins at ~1100 mph, revolves around the sun a
~67,000 mph, moves (with the solar system) around the
Milky Way at ~45,000 mph, the Milky Way hurtles through
space at ~500,000 to 660,000 miles per hour.
At this moment, the earth is in the middle of the Pliocene-Quaternary glaciation which
began ~2.58 mya. We are in an interglacial period which started btw 10k and 15k
years ago and my last ~50k years before global glaciations begins again.
Mars is red because it is
covered in iron oxide (rust).
In 1996 NASA, while studying the ALH
84001 meteorite of Martian origin
found in Antarctica in 1984, announced
that fossilized micro-organisms from
Mars might be present in it.
Mars
 1.5 AU from the Sun
 Named after the Roman
god of war (Ares)
 Iron oxide (rust) in the soil
gives it a reddish color.
 Polar ice caps made
mostly of frozen CO2 (dry
ice) & some water.
 Mars is half the size of the
Earth.
 Global dust storms.
 Ranges from -125oC at
night & 20oC during the
day.
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Phobos
Olympus Mons, the
largest volcano in the
solar system is on Mars.
Thin Martian
atmosphere of Nitrogen
& CO2
Mars has two small
moons (Phobos and
Deimos) that came from
the asteroid belt.
Deimos rises and sets twice a day.
Deimos
Phobos, is moving closer and closer
to Mars. Scientists think that one day
it will crash into Mars.
Jupiter's core is non-metal, but due to the
immense pressure inside Jupiter, the core has
become a metal. This metal is liquid metallic
hydrogen.
Jovian Planets
Jupiter
 5.2 AU from the Sun
 Named after the Roman king
of the gods. (Zeus)
 Completely made of
Hydrogen & Helium gas (gas
giant)
 Largest of the solar planets.
 Swirling bands of rotating
clouds in the upper
atmosphere.
About 1300 Earths would fit inside Jupiter and the Sun could hold about 1000 Jupiters.
Jupiter acts as a huge vacuum
cleaner, attracting and absorbing
comets and meteors. Some
estimates say that without Jupiter’s
gravitational influence the number of
massive projectiles hitting Earth
would be 10,000 times greater.
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Large rotating hurricane called the Great Red
Spot. (2 Earth sizes)
4 faint rings in orbit.
2.5 times greater in mass than all of the other
planets combined.
Has at least 63 natural satellites, 4 largest are
known as the Galilean Moons.
The Great Red Spot has been
observed for over 300 years!
Jupiter is so big that twice the
mass of the rest of our Solar
System's planets combined
would still not be enough to
equal its mass.
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Ganymede
» Largest moon in the solar system (bigger
than Mercury, but less mass.)
» Covered with a crust of rock & ice that is
heavily cratered.
» Thin atmosphere of Oxygen.
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Callisto
» 3rd largest moon in the solar system
» Most heavily cratered object in the
system.
» Thin atmosphere of CO2.
solar
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Europa
» Covered in a shell of ice
» A deep ocean beneath the ice shell.
» Thin atmosphere of Oxygen.
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Io
» About the size of the Earth’s Moon.
» Most volcanically active body in the
solar system. Erupts sulfur.
» Thin atmosphere of Sulfur dioxide.
» No craters.
Saturn
 9.6 AU from the Sun
 Named after the Roman god of agriculture.
(Cronos)
 Made of Hydrogen & Helium (gas giant)
 Flattened poles from spinning very fast.
 Less dense than water.
If you put Saturn in water it would float
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Most elaborate system of rings (rock & ice
debris)
14 or more rings.
56 or more natural satellites.
Mimas
Titan
Dione
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Titan
» 2nd largest moon in the solar system.
» Has a thick, dense atmosphere mostly of
Nitrogen & some methane.
» Surface is “squishy” & has lakes of
liquid hydrocarbons.
Saturn's moon Titan
has hundreds of
times more oil and
natural gas than all
the known reserves
on Earth.
Even though Neptune is further
Uranus
from the sun, Uranus is the coldest
planet in the solar system.
 19.2 AU from the Sun
 Named after the Greek god of the sky.
 Gas giant made of Hydrogen, Helium &
methane.
 Rotates on its side.
 System of rings.
 27 or more moons.
Uranus was originally named Georgium Sidus or “George’s Star”.
On Uranus, each
pole gets around 42
years of continuous
sunlight, followed by
42 years of
darkness.
Neptune
30.1 AU from the Sun
 Named after the Roman god of the sea
(Poseidon)
 Gas giant made of Hydrogen, Helium, &
methane.
(the methane makes it blue)
 Near-supersonic & dynamic storms.
 Faint ring system.
 13 known moons
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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.
Neptune is so far away that it took
the space probe Voyager 2, 12
years to reach it.
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Triton
» Icy, rocky surface.
» Coldest body in the solar system (- 37oC)
» Icy volcanoes & geysers erupting Nitrogen,
dust & methane
Dwarf Planets
Ceres
 2.7 AU from the Sun
 Largest object in the asteroid belt (950km in
diameter.)
 Classified an asteroid for over 150 years.
 It is believed to have a rocky core, icy water
mantle, & a thin, dusty crust.
Technically, Pluto's name is now 134340
Pluto
after being declassified as a planet.
 39.4 AU from the Sun
 Named after the Roman god of the underworld
(Hades)
 Second largest dwarf planet in the solar
system.
 Pluto’s companion, Charon , is half the size &
doesn’t orbit around Pluto.
 Pluto & Charon are small enough to fit inside
the United States.
Pluto is smaller than the
Earth's moon.
Some astronomers believe that
Pluto was once a moon of Neptune
but it somehow escaped into its
own orbit.
Eris
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67.7 AU from the Sun
Largest known dwarf planet in the solar system
with a diameter of 2400km.
At least one moon, Dysnomia.
Other Possible Dwarf Planets
 Orcus
 Sedna
 Charon
 Possibly 43 others
Other Solar Objects
Comets
 Large chunks of frozen gases, rock & dust orbiting the
Sun. (Dirty snowball)
1. Nucleus – main portion of the comet
2. Coma – thawed gases & dust form a bright cloud
surrounding the nucleus.
3. Tail – solar winds push away the gases of the coma
forming a blue ion tail & a yellowish-white dust tail.
If one were to capture and bottle a
comet's 10,000 mile vapor trail, the
amount of vapor actually present in the
bottle would take up less than 1 cubic
inch of space.
Nucleus
Coma
Ion Tail
Dust Tail
Famous Comets
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Halley’s Comet
» Most famous comet
» Returns roughly every 76 years.
 Comet Hale-Bopp
» Comet discovered by amateur astronomers.
» Last seen Spring of 1997.
The comet’s orbit was ~4,200
years but it passed close
enough to Jupiter to change
it’s orbit. It is now
~2,533 years
It will next return to
the inner solar
system around the
year 4385.
It was visible to the
naked eye for a record
18 months, twice as long
as the previous record
holder, the Great Comet
of 1811.
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Comet Shoemaker-Levy 9
» Broke into several pieces and collided with
Jupiter in 1994.
» They created several dark marks in the
atmosphere that eventually disappeared.
Asteroids
 Large chunks of rock material left over
from the
formation of the solar system.
 Most asteroids are found in the asteroid belt between
Mars & Jupiter.
If an asteroid hit the Earth, the effect would be similar to gathering
ALL the worlds’ nuclear weapons together, and detonating them.
Meteoroids, Meteors, & Meteorites
 Meteoroids are pieces of rock & dust left behind by
orbiting comets.
 Small meteoroids that burn up in the Earth’s atmosphere
are called meteors or “shooting stars.”
 Larger meteoroids that don’t burn up in the atmosphere
and hit the Earth are called meteorites.