Transcript Our Solar System

Our Solar System
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The
SunSun
is the –
center
our solar
The
ourofvery
ownsystem
star
The word “solar” means “of the sun”
Our sun is a medium-sized star
Our sun is medium-hot, and yellow
The Sun dominates the Solar
System
The Inner Planets
Terrestrial Planets
• Mercury, Venus, Earth & Mars
– “Earth-Like” Rocky Planets
– Largest is Earth
– Only in the inner solar system (0.4 to 1.5 AU)
• Rocky Planets: small, dense and rocky
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Solid Surfaces
Mostly Silicates and Iron
High Density: (rock & metal)
Earth, Venus, & Mars have atmospheres
Spinning Planets
• Period of Rotation: amount of time that
an object takes to rotate once. (1 Day)
• Period of Revolution: time it takes an
object to revolve around the sun once. (1
year)
http://www.youtube.com/watch?v=97Ob0x
R0Ut8&feature=related
Mercury
• On Mercury you weigh only
38% of what you weigh on
Earth.
• Fastest orbiting planet
• Planet nearest to the sun
• One side of the planet can be 800
degrees Fahrenheit when the
other can be -280 degree
Fahrenheit at the same time.
• Orbit Period 88 days
• Rotation Period 59 days
Mercury
• The planet Mercury is the closest of the planets to the Sun, but it
is not the hottest.
• The surface of the planet Mercury is covered with craters. These
craters have been created by eons of accidental encounters with
asteroids and comets. This is because it does not have an
atmosphere.
• Mercury is just a little bit larger than Earth's moon. The surface
of Mercury that faces the Sun can reach about 800 degrees
Fahrenheit. On the other hand, the temperature on the nighttime
side can plummet to almost -300 degrees Fahrenheit. This is
because Mercury has little to no atmosphere to help regulate
temperature.
Venus
• On Venus you weigh only 91% of what you
weigh on Earth.
• Venus has 90 times the pressure of Earth
and it’s the hottest planet.
• Venus has volcanoes like Earth
• Rotates in the opposite direction of Earth.
• One time there were oceans before they
boiled away.
• Orbit Period 224 days
• Rotation Period 242 days
Venus
• Venus rotates in a prograde rotation. The
sun comes up in the west and sets in the
east.
• Venus is the hottest planet because of its
extremely thick atmosphere of carbon
dioxide.
• Venus is know as Earth’s twin.
• Venus has no moons.
Earth
• 23 hours and 56 min=1 Earth day (rotation)
• 365 days =1 Earth year (revolution)
• Earth is warm enough to keep most of its
water from freezing and cold enough to
keep it’s water from boiling
• Temperature is between –13 degrees
Celsius and 37 degrees Celsius
Earth
• Earth is the only planet know to have life forms.
• Earth has one natural satellite, the moon.
• The ground you're walking on is recycled. Earth's
rock cycle transforms igneous rocks to
sedimentary rocks to metamorphic rocks and
back again.
• The oceans cover some 70 percent of Earth's
surface, yet humans have only explored about 5
percent, meaning 95 percent of the planet's vast
seas have never been seen.
Mars
• Air Pressure on Mars is the same as 30 km
above the Earth’s surface
• Mars is in the form of ice.
• Evidence that water was there at one time
• Volcanic history like Earth.
• It has the tallest mount of the planets (Olympus
Mons) 3x’s size of Mt. Everest.
• Orbital Period 687 days
• Rotation Period 24. 6 hours
Mars
• Mars’ red color is due to iron oxide, also known as rust, and has the
consistency of talcum powder. Literally, the metallic rocks on Mars are
rusting.
• No human could survive the low pressure of Mars. If you went to Mars
without an appropriate space suit, the oxygen in your blood would literally
turn into bubbles, causing immediate death.
• Mars has an enormous canyon named Valles Marineris (Mariner Valley)
which is an astounding 2,500 miles long and four miles deep. As long as
the continental United States, this gigantic canyon was likely formed by the
tectonic “cracking” of Mars’ crust and is the longest known crevice in the
solar system.
• Although it is much colder on Mars than on Earth, the similar tilt of Earth’s
and Mars’ axes means they have similar seasons. Like Earth's, Mars’ north
and south polar caps shrink in the summer and grow in the winter. In
addition, a day on Mars is 24 hours 37 minutes—nearly the same as
Earth’s. No other planet shares such similar characteristics with Earth.
Outer Planets
The Jovian Planets or Gas Giants
• Jupiter, Saturn, Uranus & Neptune
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Largest Planets: at least 15 times mass of Earth.
Only in the outer solar system (5 to 30 AU)
No solid surfaces (mostly atmosphere)
Low density
• Gas Giants: (Jupiter & Saturn)
– Thick H/He atmosphere, liquid hydrogen mantle, ice core
• Ice Giants: (Uranus & Neptune)
– Ice/rock core & mantle, thin H/He atmosphere
Jupiter
• Largest planet in the Solar System
• Has a Great Red Spot from a storm system
that is more than 400 years old
• Pressure is so great it would crush a
spaceship.
• Orbit Period 12 years
• 9 hours and 54 min=1 Jupiter day (shortest
day)
Jupiter
• Jupiter is the largest planet in our Solar
system.
• Jupiter has many storms raging on the
surface, most notably the big red spot which
is the largest hurricane in our Solar System.
It's been raging for over three hundred
years.
• Jupiter has many moons circling around it.
Four of these moons are bigger than Pluto.
• Jupiter also has a number of rings similar to
that of Saturn but much less noticeable.
Saturn
• 2nd Largest planet in the Solar System
• 95 times more massive than earth.
• Saturn has the largest rings of any
planet, the rings are made of icy
particles.
• Most moons of any planets ( 47 known)
• Orbit Period 12 years
• Rotation Period 10 hours
Saturn
• Many astronomers consider Saturn the most beautiful
planet in the solar system because of its stunning
rings. In fact, Saturn’s nickname is “the jewel of the
solar system.
• Saturn is the least dense planet in the solar system,
and if there were a body of water large enough to
hold Saturn, the planet would float.
• Saturn rotates so fast (6,200 miles per hour) that the
planet bulges at its equator and its poles are flat. It is
the flattest (oblate) planet in the solar system.
• Because Saturn spins on a tilt, it has seasons.
Summer on Saturn lasts about eight Earth years.
Uranus
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Discovered in 1781
Uranus appears blue-green in color
It’s axis of rotation is tilted 90 degrees
Moons are named after Shakespearean
plays and formed from other broken
moons.
• Orbit Period 84 years
• Rotation Period 17 hours
Uranus
• Uranus spins lying on its side (like a barrel), this
is perhaps due to a large collision early in its
formation.
• Uranus’s atmosphere is mostly hydrogen but it
also contains large amounts of a gas called
methane. Methane absorbs red light and scatters
blue light so a blue-green methane haze hides the
interior of the planet from view.
• It has only been visited one time
- It has 27 moons
- It can be seen without a telescope or binoculars.
Neptune
• Discovered in 1846
• The atmosphere appears blue and is
marked by large dark blue storms
• Neptune has visual belts of clouds
• It has a system of 5 rings and at least
13 moons
• Orbit Period 165 years
• Rotation Period 16 hours
Neptune
• Neptune suffers the most violent weather in
our Solar System.
• Storms have been spotted swirling around
its surface and freezing winds that blow
about ten times faster than hurricanes on
Earth make it the windiest planet.
• Neptune is a large, water planet with a blue
hydrogen-methane atmosphere and faint
rings.
• Neptune is covered in thin wispy white
clouds which stretch out around the planet.
Pluto
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Discovered 1930
Mystery Planet
Farthest from the sun
Recently changed from a
being considered a planet
to a dwarf planet.
• Orbit Period 248 years
• Rotation Period 6.4 days
Is Pluto a Planet?
What to consider?
• Size?
• Shape?
• Orbit?
• What is it made
of?
IAU Definition of a Planet
In 2006, the International Astronomical Union
(IAU) came up with the following definition of
a planet:
 orbits the Sun
 has sufficient mass for its self-gravity to overcome
rigid body forces so that it assumes a hydrostatic
equilibrium shape (i.e., it is spherical),
 has cleared the neighborhood around its orbit,
 is not a satellite
IAU Definition of a Dwarf Planet
In 2006, the International Astronomical Union
(IAU) came up with the following definition of
a dwarf planet:
 orbits the Sun
 has sufficient mass for its self-gravity to overcome
rigid body forces so that it assumes a hydrostatic
equilibrium shape (i.e., it is spherical),
 has not cleared the neighborhood around its orbit,
 is not a satellite
st
21
Century Solar System
If you traveled on a shuttle that’s
going 28,000 mph it would
take…
Mercury 52d
• Venus 100d
• Mars 210d
• Jupiter 1.9yr
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Saturn 3.6yr
Uranus 7.3yr
Neptune 11.4yr
Pluto 15.1yr
Dwarf Planets
• A dwarf planet is a celestial body massive
enough to be spherical, in orbit around the
Sun, which are not satellites. The crucial
factor dividing a planet from a dwarf planet
is that a planet must have succeeded in
clearing the area of its orbit from debris and
other objects, whereas a dwarf planet has
not.
Dwarf Planets
Mimas
Mercury
Iapetus
Miranda
Proteus
Tethys
Dione
Umbriel
Europa
Moon
Pallas
Ariel
Io
Hygeia
Triton
Titan
Ganymede
Vesta
Oberon
Callisto
Ceres
Rhea
Titania
Enceladus
Pluto
Charon
Kuiper Belt
• Class of icy bodies orbiting beyond Neptune.
– Found only in the outer Solar System (>30AU)
– Densities of 1.2 to 2 g/cc (mostly ices)
• Examples:
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Pluto & Eris (icy dwarf planets)
Kuiper Belt Objects (30-50AU)
Charon, Pluto’s large moon
Sedna & Quaor: distant large icy bodies
Kuiper Belt
The Giant Moons
• Moon: any natural satellite orbiting a planet or
dwarf planet
• Giant Moons:
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Earth: The Moon (Luna)
Jupiter: Io, Europa, Ganymede, & Callisto
Saturn: Titan
Neptune: Triton
• Many smaller moons, both rocky & icy.
• Only Mercury & Venus have no moons.
The Giant Moons
The Leftovers (small bodies)
• Asteroids:
– Made of rock & metal (density 2-3 g/cc)
– Sizes: Few 100km to large boulders
– Most are found in the Main Belt (2.1-3.2 AU)
• Meteoroids:
– Bits of rock and metal
– Sizes: grains of sand to boulders
• Comets:
– Composite rock & ice “dirty snowballs”
– Long tails of gas & dust are swept off them when
they pass near the Sun.
Asteroids
253 Mathilde
951 Gaspra
243 Ida
Comets
• A comet is an icy small Solar System body that, when close enough to
the Sun, displays a visible coma (a thin, fuzzy, temporary atmosphere)
and sometimes also a tail. Comets are often referred to as "dirty
snowballs." They are left over from the formation of stars and planets
billions of years ago. Before zipping around the Sun with their
characteristic big tails, comets that we see in our solar system start out
as big chunks of rock and ice just floating around in something called
the Oort Cloud. When the gravity from a large passing body, like a
star, becomes strong enough, some large chunks of ice get pulled away
from the cloud and head toward the Sun. As that ball of ice gets close
enough to the Sun, its heat begins to melt some of the ice that makes
up the comet. The melted ice becomes a gaseous tail that extends away
from the source of the heat (in this case, the Sun). The tail is pushed
out by the Sun's solar wind.
Comet P/Halley
Comet P/Wilt
Comet
Meteoroid, Meteorite and Meteor
• A meteoroid is a small rock or particle of debris in our
solar system. They range in size from dust to around 10
metres in diameter (larger objects are usually referred to
as asteroids).
• A meteoroid that burns up as it passes through the
Earth’s atmosphere is known as a meteor. If you’ve ever
looked up at the sky at night and seen a streak of light or
‘shooting star’ what you are actually seeing is a meteor.
• A meteoroid that survives falling through the Earth’s
atmosphere and colliding with the Earth’s surface is
known as a meteorite.
Meteor burning up in the
atmosphere.