Transcript Planets - Hays High School

Chapter 19-2
The Inner and Outer Planets
Rocket Science . . .
http://www.youtube.com/watch
?v=mmlM5XQxdMs
The Nine Eight Planets
• The term “planet” is derived from the Greek
for “wanderer” (picture not to scale)
Source: http://vathena.arc.nasa.gov/curric/space/planets/
Planets
• Five visible w/o telescope
– Mercury, Venus, Mars, Jupiter, Saturn
• Nine Eight total
– Uranus, Neptune, Pluto
– Who is Clyde Tombaugh, and why should you know?
• Moons: (define satellite)
– Earth’s: Luna, “loony,” werewolves, moonth
– Jupiter’s: Galilean (Io, Europa, Ganymede, Callisto) disc. by . . .
Galileo Galilei
– Saturn’s, Uranus,’ Neptune’s
– Pluto’s size ~ Charon’s; considered a binary system
Planets & Their Moons
The planets, to scale
The Terrestrial Worlds
Inner Planets: Overview
• Inside the asteroid belt
• “Terrestrial” planets
–Small
–Solid surfaces
–Composed of rocks & metals
–High densities
–Few satellites
Inner Planets: Mercury
• God of commerce, travel
& thievery (speed)
• Closest to sun
– Orbit didn’t behave
according to Newton’s
predictions on
planetary motion
• Caused by Vulcan?
– Reconciled by
Einstein’s General
Theory of Relativity
Inner Planets: Venus
• Ancient goddess of
beauty
• Bright, beautiful
morning/evening
“star”
• Heavily clouded
w/CO2
• Hot, sulfuric acid
• Runaway
greenhouse effect
Inner Planets: Earth
• Hydrosphere
• Thick enough
atmosphere to protect
from UV
– Mercury’s is too thin, no
protection
– Venus’ is too thick, traps
energy
• Oxygenated via
volcanic gases &
photosynthesis
Inner Planets:
Mars
Mars Rover Landing
Surface Exploration
Olympus Mons
Valles Marinaris
Polar CO2 “ice”
caps
Exobiology
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
Mars
• Two tiny moons (20 km
diameter)
• Very thin atmosphere of
carbon dioxide
• No liquid water on surface
• Mostly frigid (200 K), but
occasionally warm (290 K)
• Chance of microbial life,
especially in past
Hrad
Auqakuh
Al-Qahira
Maíadim
Harmakhis
MARS
Shalbatnu
The Red Planet
Her Descher
Ares
Huo Hsing
Bahram
WHY DO YOU THINK MARS IS
RED?
a) Mars is red because that is where men are
from. Men get red when they are angry or
embarrassed or trying to not pass gas in mixed
company.
WHY DO YOU THINK MARS IS
RED?
(b) Mars is red because it has such a thin
atmosphere, which cannot hold the blue like
the earth's atmosphere can. Mars is also red
because of all of the rusted iron dust
surrounding the planet and all the rusted iron
on the planet.
WHY DO YOU THINK MARS IS
RED?
(c) The ancient Roman god, Mars, was a great
hunter (and resident of Georgia) who was
smeared with red blood. Mars had a gun rack
on the back of his truck, and liked to shoot off
his guns on New Year's Eve. Mars was
originally called the Redneck god, but over
time, people just started saying, "Mars is
red."http://www.why-is-the-sky-blue.tv/mars-red.htm
OKAY, REALLY . . .
• FROM
http://image.gsfc.nasa.gov/poetry/ask/a
10510.html
• Mars’ is red because of the prevalence
of iron oxides (rust) on the surface.
SCHIAPARELLI
H. G. WELLS
• Lowell's theories influenced the young
English writer H.G. Wells, who in 1898
published “The War of the Worlds”
• In this novel, Wells created an invasion
of Earth by deadly aliens from Mars and
launched a whole new genre of alien
science fiction.
• Radio broadcast Halloween 1938
Mars landings (1976, 1997)
Why haven’t we gone to Mars?
• 140 times farther than the
moon (at best)
• Months of weightlessness is
crippling
• Serious radiation hazards
• Would have to carry food,
fuel, oxygen to last years
• Taking earth bacteria to
Mars could confuse search
for native Martian life
• So much to learn from
robotic exploration!
IS THE FACE ON MARS REAL?
• The "face" is nothing
more than a hill that
has been eroded by
billions of years of
Martian winds. The
original Viking orbiter
image showed the hill
illuminated from an
angle that highlighted
certain features,
creating the impression
of a face.
WATER, VOLCANOES, ICE
CAPS
• Canyon: would reach from Chicago to
LA if on Earth
• Dust storms can last for months
• Two moons, Phobos (fear) & Deimos
(panic)
http://www.kidscosmos.org/kid-stuff/mars-facts.html
VOLCANOES
• Olympus Mons,
largest volcano in the
solar system
• Covers an area about
the size of Arizona
• More than 3 times
the height of Mt.
Everest
• “Asteroid” means
“starlike”
• Also called minor
planets
– 3 to 700 km diameter
• Hundreds of
thousands have been
identified
• The largest (Ceres)
has a diameter of
1023 km
• Most in belt between
Mars and Jupiter
• Some cross Earth’s
orbit (called Apollo
objects)
Asteroids
Source:
http://www.solstation.com/stars/as
teroid.htm
Source:
http://www.mira.org/fts0/planets/
098/images/gaspra.jpg
Asteroid Belt (10/4/04)
Orbit
of
Mars
Orbit
of
Earth
Green
dots
represent
minor
planets
Orbit
of
Jupiter
Source: http://cfa-www.harvard.edu/iau/lists/InnerPlot.html
Outer Planets:
Overview
•
•
•
•
•
•
•
Outside asteroid belt
“Jovian” planets, or gas giants
Primarily hydrogen & helium
Low densities
Deep atmospheres
Rings
Many Satellites
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Outer Planets:
Jupiter
• Largest planet in solar
system
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
– Could hold 1300 Earths
– If 80x larger, would have
become a star
•
•
•
•
10-hour day
12 (Earth)years to orbit sun
Great Red Spot: hurricane
Galilean Satellites
– Io, Europa, Callisto,
Ganymede
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Jupiter
• 11 times earth’s diameter (1/10
sun’s diameter)
• 300 times earth’s mass (1/1000
sun’s mass)
• Visible surface is gas (mostly
hydrogen); interior must be
mostly liquid, with solid core
• Fascinating banded patterns,
hurricanes, great red spot
• Four large moons, many small
ones
• Visited briefly 4 times in 1970’s
(Pioneer, Voyager); orbited by
Galileo spacecraft 1995-2003
Saturn
• Prettiest planet in small
telescopes
• 9 times earth’s diameter
• 100 times earth’s mass (1/3
Jupiter)
• Gaseous surface, liquid interior,
solid core (like Jupiter)
• Rings!
• Many moons
• Visited by Pioneer 11 (1979),
Voyager 1 & 2 (1980-81);
Cassini will arrive next year for
a 4-year mission
Saturn’s rings
Rings are mostly ice particles, from tiny grains to bouldersized chunks. Gaps are created by tug of nearby moons.
Uranus
• Discovered by William
Herschel, 1781
• At the threshold of nakedeye visibility
• Less than half the size of
Saturn, and nearly twice as
far
• Another gas giant planet
with rings (faint), many
moons
• Spin axis is tipped sideways
• Visited by Voyager 2, 1986
Uranus
• Discovered by William
Herschel, 1781
• At the threshold of nakedeye visibility
• Less than half the size of
Saturn, and nearly twice as
far
• Another gas giant planet
with rings (faint), many
moons
• Spin axis is tipped sideways
• Visited by Voyager 2, 1986
Moons of Uranus
All are icy, smaller than our own moon.
Neptune
• Discovered by mathematics
(anomaly in orbit of Uranus) in
1845-46, by John C. Adams and
Urbain Leverrier
• Can be seen in binoculars (looks
like a faint star)
• About the same size as Uranus,
but 60% farther away
• Voyager 2 discovered a cool
blue spot, which has since
disappeared
• Largest moon, Triton, is a little
smaller than our own and orbits
backwards; surface is covered
with ice
In a class by itself: Pluto
• Is it a planet? (Neil DeGrasse Tyson on The
Daily Show)
– Small, rocky
– Unlike other outer planets
• Moon, Charon
– Proportionally larger than the moons of any other
planets
• Discovered by Kansan in 1930
– Clyde Tombaugh, age 24
– Of Burdett, KS
– While a teen, built his own telescopes, grinding his
own mirrors
– Asked advice from Lowell Observatory; was
offered a job
The comets
•
•
•
•
•
“Comet” means “hairy”
Thousands have been
identified but the total
population may be 10
trillion
Total mass may be
greater than Jupiter’s
Divided into short-period
and long-period comets
Located in two areas:
– Kuiper belt
– Oort cloud
Source:
http://www.solarviews.
com/browse/comet/hal
ebop2.jpg
Source:
http://www.solarviews.
com/raw/comet/west.g
if
Where the comets live
Source: http://www.solarviews.com/browse/comet/kuiper3.jpg
The Oort cloud
Source: http://spaceguard.esa.int/NScience/neo/neo-what/com-oort.htm