Title: Seasonal and Daily Changes on Mars
1Seasonal and Daily Changes on Mars
- Global and local dust storms
- Dust devils
- Eroded rock and dunes
- Polar Caps and their variation by season
- Layers within caps
- Other cold-climate features
- Cause of climate changes on Mars?
2Global dust storms evolve in lt 1 months, and last
gt 3 months
3Dust Storms
4Dust storm
Polar cap
Dust storm
Africa
Local dust storm on Mars
Dust storm from Sahara
5(No Transcript)
6 Dust devil tracks evidence for local winds and
surface fines
7Wind-scoured rocks are called Yardangs
8(No Transcript)
9The material eroded from rocks forms many
dunes. Show constant wind direction for long
periods of time.
10Wind erosion features on Mars
11North Polar Cap
Water (H2O) ice
Low elevation
12South Polar Cap
Carbon dioxide (CO2) ice
High elevation
13Changing shape of the South Polar Cap due to
seasons
Frost
Cap
Spring
Winter
Summer
MOLA data indicate that this eroding layer is
about 10 cm thick
14Polar Caps composed of hundreds of layers of ice
and dust
15Snow melt as possible mechanism for pit erosion
16Polygonal ground as indicator of freeze-thaw
process
17So how do we get these longer seasonal changes on
Mars?
The obliquity of Mars may have varied from
almost 0 60 degrees
The precession may have changed climate
dramatically in the past on timescales of 25,000
175,000 years
18Temperature change on Mars due to change in
eccentricity
19Present and past climates of Mars may be very
different
Present cold/dry
Past cold and moist
20Results from Viking Lander Gaschromatograph -
Mass spectrometer
21- Viking Biology Experiments
- Labeled release experiment, looked for signs of
metabolism - Pyrolytic release experiment, looked for signs of
photosynthesis - Gas exchange experiment, looked for signs of
respiration
22In 1996, possible fossils were found in a
meteorite from Mars!
ALH 84001 originated as a slowly-cooled igneous
rock in the Martian crust, was excavated by an
impact, altered by fluids, and finally sent to
Earth by another impact. The consensus among most
researchers is that these are not fossils
butludae naturae (playthings of nature), of
inorganic origin.
23More pseudofossils from Martian meteorite ALH
84001
24Carbonates in Martian meteorite ALH 84001 formed
by shock
25Carbonate globules in Martian meteorite ALH 84001
are of inorganic origin
26(No Transcript)