Transcript 3 Sept 2003 Solar System - C. C. Lang Check your knowledge-- Northerners have cold days in January because: (a) the earth is.

3 Sept 2003
Solar System - C. C. Lang
1
Check your knowledge--
Northerners have cold days in January because:
(a) the earth is farthest from the Sun in January
(b) the orbital velocity of Earth is greatest in Jan.
(c) the Sun is lower in the sky in January
(d) El Nino is always strongest in January
ANSWER: (c)
3 Sept 2003
Solar System - C. C. Lang
2
Physical Features of Mars
• The Martian Surface as revealed by the Mariners, Vikings
- craters
- volcanoes
- plains
• Evidence for Water on Mars
- geological
- chemical
• The Martian Atmosphere
3 Sept 2003
Solar System - C. C. Lang
3
Fast Facts on Mars:
• size = 5974 km/4200 miles
~53% Earth’s size
• mass = 6.5 x 1023 kg or
0.1 Earth’s mass
• density = 3900 kg/m3
(Earth’s density = 5510 kg/m3)
• gravity/physics will be
different on Mars, i.e., mts.,
activity in planet’s core
3 Sept 2003
Solar System - C. C. Lang
4
Solar System
- C. C. Lang
Changes in surface coloring:
thought
once to be vegetation!!
3 Sept 2003
5
Mariners 6 and 7
Fly by of Mars on 31 Jul 1969
- came within 2,130 miles of Mars
- pictures of ~20% surface (missed important volcanic features)
- sent back ~80 photos (Mar. 6) and ~120 photos (Mar. 7)
Mariners 6 and 7 had scientfic instruments to study Martian atmosphere:
- composition, pressure, density, and temperature
- two cameras
- infrared spectrometer
3 Sept 2003 - ultraviolet spectrometer
Solar System - C. C. Lang
6
Martian surface covered with craters!
- surface isn’t smooth (as historical observations thought)
3 Sept 2003
- similar to Moon surface (being studied simultaneously)
- must be old: peak in impacts ~3.8 billion years ago
- difficult to see from Earth, but Mars’ thin atmosphere
Solarfor
System
- C. “water”/
C. Lang “life” on Mars
- many gave up hope
seeing
7
Mariner 9 – first ORBITER spacecraft!!
3 Sept 2003
Solar System - C. C. Lang
8
• Mariner 9 was the first spacecraft to orbit another planet
- arrived at Mars 14 November 1971
- orbited Mars for more than a year
• Major dust storm on Mars when Mariner 9 arrived!
-surface was not visible for an entire month
-however, the cones of major volcanoes (new discovery) were visible
3 Sept 2003
Solar System - C. C. Lang
9
Craters weren’t all that was found on Mars!!
Even though dust
covered, there were
several ‘crater-like’
features visible rising
above the dust...
Picture from Mariner 9
during the dust storm
(ignore black dots)
Carl Sagan took a polaroid of the TV screen in the headquarters of Mariner 9 – he rushed into a
3 Sept
System
- C. C. Lang
group
of 2003
scientists in the next roomSolar
and they
realized
that these were volcanic calderas!!10
Mariner 9’s Mars Milestones
• 349 days in orbit (circled Mars twice daily for a year)
• Mariner 9 transmitted 7,329 images, covering over 80% of Mars' surface
• lowest altitude images distance of spacecraft ~900 miles above surface
• An infrared radiometer was included to detect volcanic activity
• Mars' tiny moons, Phobos and Deimos, were also photographed.
Channels on the flanks of the
volcano Hecates Tholus. Various
radial channels have been interpreted
as erosional ash channels,
lava channels or channels eroded
by fluvial processes.
Mariner 9 narrow angle camera.
3 Sept 2003
Solar System - C. C. Lang
11
The images revealed structures
resembling river beds
Extinct volcanic activity!
3 Sept 2003
Olympus Mons – 3x as high
as volcanoes on Earth
Solar System - C. C. Lang
12
Valles Marineris – picture from Mariner
Valles Marineris - system of canyons over 4,000 km (2,500 miles)
3 Sept 2003
Solar
System - C. interest
C. Lang
- revived
people’s
in possible water/life13
Valles Marineris - “Grand Canyon of Mars”
- streches for at least 2500 miles (NYC  LA)
- “rift valley” – region broken by crust motions earlier in Mars’ history
 signs of river erosion in early history of
Mars (3-4 Billion yrs ago) like Grand Canyon
3 Sept 2003
Solar System - C. C. Lang
14
Viking 1 and 2 – Orbiter & Lander
3 Sept 2003
Solar System - C. C. Lang
15
Viking Orbiter
• This image is a mosaic of the
Schiaparelli hemisphere of Mars.
The center of this image is near
the impact crater Schiaparelli,
450 kilometers (280 miles) across!.
• Bright white areas to the south,
including the Hellas impact basin
at extreme lower right, are covered
by carbon dioxide frost.
3 Sept 2003
Solar System - C. C. Lang
16
Viking Orbiter
• This image is a mosaic of the
Valles Marineris hemisphere of Mars.
• The center is the Valles Marineris
system – 3,000 km (1,860 miles) long
and up to 8 km (5 miles) deep.
• Many huge ancient river channels
begin from the chaotic terrain and
north-central canyons and run north.
• Many of the channels flowed into a
basin called Acidalia Planitia, which
is the dark area in the extreme north.
• The three Tharsis volcanoes (dark
red spots), each about 25 kilometers (16
miles) high, are visible to the west.
3 Sept 2003
Solar System - C. C. Lang
17
Changes in color across Mars’ Surface
- first thought to be vegetation!
- changes over seasons (growing seasons?)
now understood physically:
- changes in the surface features
(i.e. plains, volcanoes, crater beds)
- changes in the surface
chemical composition (rock, soil
types – e.g., basalt) determined
from spectroscopy (radar) of
reflected light from the surface
- albedo – measure of the
reflectivity of a planet
3 Sept 2003
Solar System - C. C. Lang
18
Mars Global Surveyor
- NASA launched in December 1996
- 6 instruments including
MOC – high resolution camera
MOLA – laser altimeter (first 3D look!)
TES – high-resolution temperature detector
Magnetic field detector
How do we measure the height of features on Mars?
Laser Altimeter (MOLA)
bounce laser beams off surface
time delay between signals gives height measure
plot of Mars’ height as a function of position on the planet – North to South
3 Sept 2003
Solar System - C. C. Lang
19
The “Face” on Mars (Viking Image from 1976)
Mars Global Surveyor (1998)
3 Sept 2003
Solar System - C. C. Lang
20
Radar map of
Martian
surface
Low area:
Former Ocean?
MOLA
(Mars Orbiter
Laser
Altimeter)
Color indicates
elevation
(Blue =low,
red= high)
3 Sept 2003
Solar System - C. C. Lang
21
Mars Topographic Map
(MOLA radar 1998/99)
Low elevation Northern hemisphere
Volcanoes
- Resurfaced by some process??
Hellas impact
basin (2000 km)
Valles Marineris
(2500km)
High elevation southern hemisphere
Many more craters! “Older surface”?
3 Sept 2003
Solar System - C. C. Lang
22
Mars’ Crustal Dichotomy =
noticeable differences between N and S hemispheres
- Altitudes (N lowlands, S highlands)
- Cratering (age of surfaces?)
Various Explanations:
- large impact (asteroid) on Mars
- plate tectonics (although Mars too small for hot core)
- volcanic eruptions which smoothed parts of the planet
3 Sept 2003
Solar System - C. C. Lang
23
Hellas Impact Basin
 2000 km diameter, 9 km deep!
 Probably formed by asteroid
impact
 Debris from collision would cover
US with layer 3 km thick
3 Sept 2003
Solar System - C. C. Lang
24
Olympus Mons – largest volcano in S.S.
• rises 15 miles above
surrounding flat plains
• three times as tall as
Mt. Everest
• “hot spot” volcanism
like in Hawaiian Islands
(magma lifts up underneath)
• caldera is ~70 km across
3 Sept 2003
Solar System - C. C. Lang
25
Tharsis Rise – cluster of large volcanoes
• near Olympus Mons
• blue/white clouds often
seen over these volcanoes
• these clouds result when:
- warm air (water) rises
- cools at the high altitude
- freezes into cloud
3 Sept 2003
Solar System - C. C. Lang
26
This powerpoint was kindly donated to
www.worldofteaching.com
http://www.worldofteaching.com is home to over a
thousand powerpoints submitted by teachers. This is a
completely free site and requires no registration. Please
visit and I hope it will help in your teaching.
3 Sept 2003
Solar System - C. C. Lang
27