Time to think…… When can you observe Mars? a) sunrise b) noon c) sunset d) midnight
Northern Lowlands Southern Highlands
Theories of Dichotomy • Large impact on northern hemisphere • Problem: edges not very smooth • Plate tectonic activity • Northern hemisphere was an expanding ocean • Analogous to Atlantic Ocean on Earth
Time to think…… Work out ‘Exercise I. Martian Features’ in class activity ‘Mars’.
Time to think…… Work out ‘Exercise II. Martian Atmosphere’ in class activity ‘Mars’.
Seasons in hemispheres differ • Due to elliptical orbit • Summer in southern hemisphere occurs at perihelion, at aphelion in northern hemisphere • Atmospheric pressure drops during southern hemisphere’s winter • At midsummer, southern hemisphere’s ~150 K, while the northern hemisphere’s ~200 K
Takes ~3 days to set after rising P = 7 h 39 m
Time to think…… Recall Phobos orbits Mars in about 7 hours, Deimos orbits slightly slower than geosynchronous orbit and a Martian day is 24 h 37 m. Which of the following will eventually occur? a) Phobos will eventually fly away b) Phobos will keep getting closer and closer to Mars c) Phobos will be struck by Deimos d) Nothing, Phobos will remain in its present orbit forever