Transcript File - Mr. Dudek`s Science

Planet Motion
Chapter 8, Section
1
Models of the Solar System
• The Ancient Greeks believed in the
geocentric model.
• In the geocentric model, the Earth was at
the center of the universe and that the
stars consist of two spheres; one that was
consistently spun around the Earth and
one that seemed to wander (planet
translates to “wandering star”)
Ancient Greek (Ptolemy)
Geocentric model
• The Ancient Romans did not seek out
much in terms of science about the
cosmos.
• They did however name three days of the
week after it:
– Saturday – Saturn
– Sunday – Sun
– Monday – Moon
– (The other four were named after Norse
gods; Tiu, Woden, Thor, & Friya)
• In the geocentric model, the solar
system would have been arranged
in the following order:
A map of the Geocentric
model
Copernicus
• In 1543, Copernicus came up
with the heliocentric model
• Stated that the moon revolved
around the Earth and all of the
planets revolved around the sun.
(Helios was the Greek god of the
Sun.)
• Did not count on ellipses and
thus his model could not
accurately predict the location of
the planets and was not widely
accepted
Galileo
• Found that Venus has phases
much like our moon
• Found that Jupiter has moons
that revolve around it.
• This evidence further supported
the heliocentric model.
• He invented the modern
telescope and was the first
person to document sunspots.
• Was forced by the church to
recant all his findings 6/22/1623
Kepler
• Mathematician who
took the work of
other astronomers
and put it together.
• Found that the
paths of planets
were ellipses
• Planets travel at
different speeds.
Understanding the Solar
System
• In the early 1600s, a German
mathematician Johannes Kepler
calculated the speeds of the planets and
found that they were ellipses.
• He also learned that the speed of each of
the planets was different and the outer
planets took much longer to orbit the Sun
(Mercury=88 days, Saturn= 29.5 years).
• In the heliocentric model, the solar
system would have been arranged
in the following order:
• Scientists now use two units to measure
distance in space:
– one is the astronomical unit which is
equal to the average distance
between the Earth and the Sun, and
the light year which is the distance
traveled by light in space in one year.
(L.Y. = 9.5 Trillion km)
• By definition, there are eight planets
which consist of four terrestrial planets
which are closer to the Sun and four
gaseous giant planets which are further
away. The terrestrial and gas planets
are separated by a belt of rocky debris
known as the asteroid belt.
• Beyond the orbit of the gas giants are
no less than 100 small planet-like
objects known as planetoids (including
Pluto).
• The solar system also contains a sizable
collection of meteors, comets, and belts
of rocky materials that also orbit the Sun.
• The solar system is thought to have
formed from a condensing cloud of gas
and dust known as a nebula. As the
cloud contracted, it became super-heated
and created our Sun. The remaining dust
and gasses condensed into the planets.
Other Solar systems
• So far, over 300 stars have been found to
have planetary systems.
• Upsilon Andromedae is one star with
planets around it.
The Inner
Planets
Chapter 8, Section
2
Planets near the Sun
• The solar wind
and heat have
all but stripped
most of the
gases and
lighter elements
off of the
terrestrial
planets.
(Planet size ratio is not accurate)
Mercury
• Smallest of the planets; size of our moon
• Has no atmosphere
• Surface temperatures vary from 427°C to
-170°C
Mercury
• Taken by
Mariner 10
• Mercury in color
Mercury view from sun
Venus
• Size and mass similar to Earth
• Surface pressure is 92x greater than
Earth
• Atmosphere is almost entirely CO2
• Surface temperatures vary from 450°C
to 475°C
• RETROGRADE ROTATION:
Backwards rotation of a planet
Venus
• As seen
from
Earth
Venus
• As pictured
by
Magellan
spacecraft
• It takes 223 days for Venus to
revolve.
• Rotation takes 243 days! Notice
something????
• Thousands of volcanoes
• Silicon and Oxygen in crust
The Surface of Venus
Radar Images of Surface
Venus in front of the sun
Earth
Earth
• Allows water to exist as a solid, liquid,
and a gas
• Atmosphere burns up most meteors
before they hit the ground
• Ozone in the atmosphere protects the
life from U.V. rays
• Temp. range: -88 to 58°C
Mars
• Known as the red planet due to the high level of iron
oxide (rust)
• Has polar ice caps
• Appears to have once had flowing water on its
surface
• Mars is tilted 25° on its axis and has seasons
• Atmosphere is mostly CO2 and does not filter out
harmful rays
• Surface temperatures vary from 37°C to -123°C
• Mars has two small moon; Deimos and Phobos
• ½ size of Earth!
Mars
NASA on Mars
• NASA sent probes to Mars in the 1970s
and 80s but much more detailed
information has come from the Mars
Rovers; Spirit and Opportunity
• In 1996, structures identical in nature to
some bacteria were found fossilized in a
fragment of rock from Mars.
Mars Rover
A Face on Mars?
How Disappointing!
Evidence of Water?
Sunset on Mars
Olympus Mons: Largest Volcano
in Solar System
• Three times taller
than Mt. Everest
• 342 miles across
What do the inner planets have in
common?
• small
• Planets with a solid surface are
called terrestrial
• Contain iron cores
• Crust contains heavier elements
The Outer
Planets
Chapter 8, Section
3
The Outer Planets
• Why are the outer
planets so different?
• The outer planets
have large amounts
of lighter elements
such as H and He.
• Are not as affected
by the solar wind
than the inner
planets
Jupiter
• Is the largest planet
• Composed of hydrogen and helium
SIMILAR TO THE SUN!
• As you get closer to the surface, the
pressure is equal to 50 million Earth
atmospheres and the temperature is apx.
20,000°C
• Thin rings
• Has continuous storms that cause swirls in
the atmosphere
• Has more than 60 moons, of which Io,
Europa, Ganymede, and Callisto are
thought to have water and conditions
possible for life to occur
Jupiter
Jupiter
with moons
Comet that struck surface in ‘94
Eclipses on Jupiter
Aurora on Jupiter
Saturn
• Saturn is the second largest planet;
HYDROGEN AND HELIUM!
• Has rings made of chunks of rocks and ice
• Has 53 moons
• The largest is Titan
Saturn
Saturn Edge View
Saturn Surface
Saturn Aurora
Uranus
• Axis is tilted on its side (north to south)
• Has a blue/green color due to its methane
atmosphere
• Has 27 moons
Uranus
Uranus
with rings
Infrared Image of Uranus
Neptune
• Was actually predicted by mathematical
calculations before it was ever seen (It was
known that an object was affecting Uranus’
orbit)
• Has blue color due to methane in its
atmosphere
• Has 13 moons
• The largest is Triton
– Has poles covered in ice
– Has eruptions
Neptune
The Great Dark Spot
What do the outer
planets have in common?
• Large and gaseous
• Have rings
• H and He make up atmospheres
• Many moons
• Iron cores
Planetoids (Pluto)
• Is smaller than the Earth’s moon
• Has its own moon, Charon
• Another planetoid is Sedna
Pluto and Charon
Comets and other objects
• Comet – dust, ice, frozen water, methane,
and ammonia, ROCK!!!
• Asteroids – chunks of rocks (>10 meters)
• Meteoroids – chunks of rocks that can
pass through the Earth’s orbit and into the
atmosphere of the Earth; SOME OF
THESE ARE LEFT BEHIND BY COMETS
• (<10 meters)
Comet
Hale~Bopp Comet
Asteroid
Another Asteroid
• Asteroid
belt
between
Mars and
Jupiter
Meteor vs. Meteoroid. vs. Meteorite
• METEROID: a rock that travels aimlessly in
space
• METEOR: a streak of light we see when a
rock is burning up in the atmosphere
• METEORITE: if the rock makes it to the
ground, it’s now a meteorite.
Meteoroid
Meteors: known as shooting stars!
Meteor Shower: Leonid
Meteorite!
When Meteors Attack
Chapter 8,
Section 4
Is There Life
Beyond Earth
Life on other worlds?
• All living things contain CARBON on Earth
• Most life forms on Earth need water and a
comfortable temperature…….but……
• Life has been found to exist in places with
extreme living conditions on Earth
• These extreme living conditions include scalding
hot areas, freezing cold areas, completely dark
areas, etc.
Life on Europa, Jupiter’s Moon
• The surface is covered in large moving
chunks of ice that are possibly made of
frozen water.
Europa, Getting Closer…
Close up of Europa
Titan, Saturn’s Moon
• Nitrogen
atmosphere….don’t plants
on Earth use nitrogen?
• Contains
hydrocarbons…isn’t life on
Earth based on carbon?
• Surface pics show old
riverbeds of ethane….and
liquid METHANE!!! These
are hydrocarbons.
Titan’s Surface from Sky…
yes, it’s real
Titan’s
surface