Planets {Mars, planet} can be fourth nearest to Sun.
properties
Diameter is 6,800,000 meters. Mass is 12% Earth mass. Density is 4 g/cm^3. Gravity is 38% Earth gravity.
properties: rotation
Mars rotates every 24.5 hours on axis inclined 23 degrees to orbit.
properties: orbit
Mars is 227,000,000,000 meters from Sun. It has slightly elliptic orbit of 1.88 years, slightly inclined to ecliptic.
properties: magnetism
Mars has no magnetic field.
properties: temperature
Surface temperature is 250 K, with high 290 K.
formation
Rapid matter accretion at solar-system beginning melted crust in just 10^5 years. Then iron and iron-sulfur core formed. Crust cooled. Plains and volcanoes formed 3.5 x 10^9 years ago. Crust has no plates or movement. Crust has stretched since forming.
surface
North is low plain with few craters. South is highlands with many craters. Tharsis Plateau is at equator, with very high volcanoes. Volcanoes are over hot spots around equator.
surface: sand
Surface has rocks and red dust. Sandstorms are 300 km/hr. When Mars is farthest from Sun, great dust storm lasts 3 months.
surface: rocks
Mars has magnesium and iron silicates, iron-sulfur rocks (troilite), and free iron. Dark regions have basalt, such as plagioclase and pyroxene. Northern plains are andesite. Hematite is near equator.
surface: water
Surface has phyllosilicate clays and hydrated iron oxides, which indicate water, but no carbonates. Surface has sedimentary rocks with sulfur and hydrates. Sulfur degrades carbonates and inhibits clay formation. Mars dried out and cooled between 3.5 billion years ago and 2.5 billion years ago. Water ice extends deep into surface, except at equator.
surface: ice caps
Polar ice caps are water ice with some carbon-dioxide ice. At maximum, they are 10% of surface. Layered regions near poles show changes.
atmosphere
Mars has thin atmosphere, with surface pressure 0.01 atmosphere. Atmosphere has carbon dioxide, water traces, and no oxygen. Clouds are over volcanoes. Thin clouds are over poles.
landmarks
Nix Olympia or Olympus Mons is 15 miles high and 370 miles across. Mars Rift Valley is 3000 miles long and 1500 miles wide. Coprates is a large river-like system. Hellas crater is a featureless bowl-shaped region. Valles Marineris canyon is north of south highlands. Argyre Basin has 1000 km diameter.
moons
Two small moons are in rapid close orbit. Phobos is larger, and Deimos is smaller.
Physical Sciences>Astronomy>Solar System>Planet>Planets
5-Astronomy-Solar System-Planet-Planets
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Date Modified: 2022.0224