What caused the accretion phase to end newly formed

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What caused the accretion phase to end? Newly formed stars have stronger winds than older stars. The Sun’s strong solar wind and radiation blew remaining gas out of the solar system. Heavy bombardment period? Most planetesials collided with planets or were flung into deep space Why is the asteroid belt between Jupiter and Mars? Jupiter’s tidal forces prevented a planet from forming Why are there few asteroids and comets nearby planets? kicked into the outer solar system by gravitational encounters with the planets. Differences between Kuiper Belt and Oort Cloud? Kuiper Belt: The remaining outer disk of the solar nebula, beyond Neptune’s orbit. The Oort Cloud: Extreme outer regions of solar system. Surrounds the Sun in a spherical shell. What probably caused the “exception to the rules” back-wards rotation of Venus and extreme tilt of Uranus? series of smaller shifts through orbital migrations and interactions between the giant planets during the earliest stages of Solar System formation How old is the Solar System? 4.55 billon years; Age of the Sun confirms this age for the solar system. Layers of the rocky interior: Crust, Mantle, Outer Core, Inner core Lithosphere? The solid, brittle part of Earth (or any planet or moon), including the crust and the upper part of the mantle. Smaller planets/moons have thicker lithospheres. Why are planets and large moons round? In a large enough world, gravity is strong enough! to deform even solid rock, and mold it into spherical shape over time. If an object is smaller than a dwarf planet, its! gravity is not strong enough to do this, and it! will be irregular in shape. What is the main indicator of whether or not a planet will have a lot of geological activity? The hotter the interior of a planet, the more geological activity it has. Earth’s interior is hot enough to melt rock into molten lava, but the moon’s isn’t. What causes planet interiors to heat up? Heat: accretion, differentiation, radioactive decay. Cool Down: convection, conduction, radiation. Smaller planets cool of faster than larger ones. What causes magnetic fields around planets? Accelerating charges. To have a magnetic field: Liquid metal core, convection, fast rotation 4 main processes that change planetary surfaces: Impact cratering: asteroids or comets hit the surface, creating bowl- shaped impact craters. Volcanism: the occurrence of volcanic activity on a planet or moon. Tectonics: deformation of the lithosphere of a planet. Erosion: the degradation of a planet’s topography by the mechanical action of wind and/or water. Plate tectonics: the geological theory concerning the motions of the lithospheric plates, which in turn provides the theoretical basis for continental drift. Volcanoes? Thin lave flows far, spreads out, and flattens before solidifying, creating flat volcanic plains. Thicker lava doesn’t spread out as much, creating shallow shield volcanoes . The thickest lava is made of lower-density rock: it hardens very fast, and makes tall, steep stratovolcanoes. Volcanism and tectonics? The moon and Mercury (small: cooled of quickly); no current volcanism or tectonics. Earth and Venus (large: still a lot of internal heat): ongoing volcanism/tectonics. Erosion depends on? Size, distance from sun, rotation Impact craters: The number of craters gives the geological age of the surface: how long it’s been since geological activity wiped out older craters.
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