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Geology of Venus

Geology of Venus. Geology of Venus. Venus’ surface is similar to Earth and Mars – few impact craters, volcanoes, and evidence of tectonics activities… But no plate tectonics The volcanoes of Venus is most likely still active today few impact craters,

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Geology of Venus

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  1. Geology of Venus www.assignmentpoint.com

  2. Geology of Venus • Venus’ surface is similar to Earth and Mars – few impact craters, volcanoes, and evidence of tectonics activities… • But no plate tectonics • The volcanoes of Venus is most likely still active today • few impact craters, • sulfuric acid cloud (the volcanoes are still outgasing) • However, there is no sign of erosion • No liquid water? • No wind, due to its slow rotation (243 Earth days per rotation). www.assignmentpoint.com

  3. Venus and Earth are near-twins in size, mass, composition, and (from their positions in the Solar System) conditions when they formed. • Like Earth, Venus has a large iron core and rocky silicate mantle. Its crust is largely basalt (again, like Earth). www.assignmentpoint.com

  4. Venus dos not have a magnetic field! • This is quite surprising given that most of the ingredients required for the dynamo are all present… www.assignmentpoint.com

  5. NASA Image of Venus Venus We cannot see the rocky surface of Venus due to its thick atmosphere... www.assignmentpoint.com

  6. Why doesn’t Venus have water? • Given the similarities between Earth and Venus, why is the atmosphere of Venus so different from Earth’s? • Venus is too hot! • The proximity to the Sun keep the temperature on Venus high, even without greenhouse effect. Any water on Venus (from out-gassing of water trapped inside the planet) are vaporized into gaseous phases (water vapor). • Water vapor and CO2 are both greenhouse gas, causing the atmosphere to warm up more runaway greenhouse effect T = 740 ºK • At 740 ºK, the molecules of gases has much higher average kinetic energy (recall the definition of temperature)  higher average velocity. • If the velocity of the gas molecules exceed the escape velocity, then they can escape into space… • Light gases (H, H2O, O2, N2) escape, heavy gases (CO2) stay. Why? • Without liquid water, CO2 doesn’t have a place to go, except to stay in the atmosphere…in comparison, most of the CO2 on Earth are locked in rock or liquid water... www.assignmentpoint.com

  7. Is Venus still geologically active? The observations reveal that volcanoes on Venus appeared to erupt between a few hundred years to 2.5 million years ago. This suggests the planet may still be geologically active, making Venus one of the few worlds in our solar system that has been volcanically active within the last 3 million years. www.assignmentpoint.com

  8. What makes a planet habitable? Two important factors determine whether a planet is habitable… Size: • Need substantial mass to maintain an atmosphere • Small planets cool off faster than large ones. Without the volcanic outgasing and a hot, fluid metallic core to generate magnetic field, atmospheric gas are easily depleted. Distance to the Sun – the distance to the Sun determine the energy input to the planet: • Too close  too hot – water evaporates. • Too far  too cold – water freeze. www.assignmentpoint.com

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