ASTR 151 Chapter 10
Popular in Journey Thr Solar Sys Lecture
Popular in Astronomy
This 4 page Class Notes was uploaded by Wesley Fowler on Friday April 22, 2016. The Class Notes belongs to ASTR 151 001 at a university taught by Dr. Sean Lindsay in Spring 2016. Since its upload, it has received 10 views.
Reviews for ASTR 151 Chapter 10
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/22/16
Wesley Fowler ASTR Chapter 10 Mars th Distance from Sun: 1.52 AU (4 planet from the Sun) Radius: 3,390 km (0.52 Earth radii) Mass: 6.4 x 10 kg (0.11 Earth Masses) Average Density: 3,900 kg/m (LOW density) 3 *Average density of surface rocks: 2,500kg/m Mean Temperature: 210 K (81.4 F) o Max Temperature about 300 K Does have an atmosphere: Very thin (6% of Earth’s) Does not have a magnetic field: No longer exists Mars’ Orbit Orbital Period: 1.88 years (~687 days) Rotational Period (Sidereal Day): 24 hrs 37 min Semimajor Axis: 1.52 AU Eccentricity: 0.094 - Closest Opposition: 0.37 AU (Distance between Mars and Earth when closest to Earth) - Opposition to opposition roughly every 780 days. This is Mars’ synodic period. Martian days are called sols Mars’ axial tilt (obliquity) changes from 10 to 60 over very long periods of time Mars’ Surface Has polar ice caps that show seasonal variability - Lowland Northern hemisphere: Smooth volcanic plains - Highland Southern hemisphere: Dark mountains Crater counting dates volcanic activity around 100 million years ago Surface Features Tharsis bulge: Contains four huge volcanoes - Size of North America, 10km above surface Olympus Mons: The largest volcano on Mars, being 700 km across it covers a surface area equal to the size of Arizona. - Sticks out of atmosphere Hellas Basin: Large impact basin in the southern hemisphere. Valles Marineris: Huge canyon, the biggest in the solar system - 4000km long, deepest at 7km Water on Mars Runoff channels: Large, ancient river bed systems - Mostly in southern highlands - Active 4 billion years ago, which is the same as Mars’ atmosphere - Formation of clays - Suggest a wet period 4 billion years ago when the atmosphere was thick enough to support liquid water Outflow channels: Young areas characterized by a catastrophic flood - Only appear in equatorial regions, closer to northern lowlands - Have tear-drop shaped “islands” - 3 billion years old - Suggest a wet period about 3.7-3 billion years ago by a catastrophic period of flooding, possibly caused by the melting of ice on Mars. Water-ice currently exists on the surface of Mars. The higher latitudes have permafrost layers. - Supported by fluidized ejecta features: Water underneath the surface ejecting out from an impact Recurring Slope Lineae (RSLs): Long dark streaks associated with hydrated salts. These disappear in colder temperatures. Where did the water go? 1. Into the subsurface where it remains frozen 2. Lost to space via the photodisassociation of H O into H 2and O . H2ving so 2ittle mass, the H can easily escape the low Martian gravity and escape to space, and the oxygen 2 reacted with surface 3. Some locked in permanent North Polar Cap Martian Polar Caps Mars’ ice caps are predominantly made of dry ice (CO ice), howeve2 residual North Polar Cap is made of water-ice. - Mars’ eccentricity leads the southern cap to generally be larger than the northern cap The seasonal caps grow and shrink each year - Composed of almost entirely carbon dioxide with temperatures lower than 150K - Southern ~4,000km Northern ~3,000km - Growth and shrinkage alters atmospheric pressure by around 30% The residual cap remains permanently frozen - Brighter and smaller than seasonal caps, - Southern ~350km almost all CO 2 - Northern ~1000km almost all water ice Mars’ Atmosphere With no magnetic field to protect itself, Mars’ atmosphere was eroded away by solar wind - Mars lost its global magnetic field 4 billion years ago - Mars’ troposphere disappears at night because it’s too cold Composition: 95.3% CO 2 2.7% N 2 0.13% O 2 0.07% CO 0.03% water vapor Dust Storms: - Global dust storms once ever 5.5 years - 1-3 continent sized dust storm per Martian year Dust Devils: - Low wind speeds, bigger than Earth’s tornados Mars’ Interior Core believed to be between 1,500 and 2,100km in radius. 3 - Average density = 3900 kg/m (made of iron sulfide) Crust is about 50km thick Volcanos indicate Mars having a convective mantle Mars’ Moons Phobos and Deimos (fear and panic) - Only other terrestrial planet to have a moon - Moons are small compared to the Earth’s - Origin highly debated: possibly captured asteroids - Irregular in shape, look like asteroids - Very dark, albedo is ~0.06 Phobos’ most distinct feature is the 10km wide Stickney Crater. The impact should have destroyed Phobos. Deimos is the smaller one.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'