Magnetic Field and Structure
Venus's crust appears to be 50 kilometres (31 mi) in thickness, and composed of silicate rocks. Venus's mantle is approximately 3,000 kilometres (1,900 mi) thick, but its composition is unknown. Since Venus is a terrestrial planet, it is presumed to have a core made of semisolid iron and nickel with a radius of approximately 3,000 kilometres (1,900 mi).
Pioneer Venus Orbiter data indicates that Venus does not have a significant magnetic field. The magnetic field of a planet is produced by a dynamo in its core. A dynamo requires a conducting liquid, rotation, and convection. Venus is thought to have an electrically conductive core, and although its rotation period is very long (243.7 Earth days), simulations show that this is adequate to produce a dynamo (Stevenson 2003). This implies that Venus lacks convection in its core. Convection occurs when there is a large difference in temperature between the inner and outer part of the core, but since Venus has no plate tectonics to let off heat, it is possible that it has no inner core, or that its core is not currently cooling.
Read more about this topic: Geology Of Venus
Famous quotes containing the words magnetic, field and/or structure:
“We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate.”
—Henry David Thoreau (1817–1862)
“An enormously vast field lies between “God exists” and “there is no God.” The truly wise man traverses it with great difficulty. A Russian knows one or the other of these two extremes, but is not interested in the middle ground. He usually knows nothing, or very little.”
—Anton Pavlovich Chekhov (1860–1904)
“I’m a Sunday School teacher, and I’ve always known that the structure of law is founded on the Christian ethic that you shall love the Lord your God and your neighbor as yourself—a very high and perfect standard. We all know the fallibility of man, and the contentions in society, as described by Reinhold Niebuhr and many others, don’t permit us to achieve perfection.”
—Jimmy Carter (James Earl Carter, Jr.)