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17 Cards in this Set
- Front
- Back
Kepler's first law of planetary motion
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each planet orbits around the Sun in an ellipse with the Sun at one focus
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Kepler's second law of planetary motion
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planets cover equal distances in equal times throughout their orbits
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Kepler's third law of planetary motion
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the time a planet takes to complete an orbit is related to its average distance from the Sun
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Eccentricity
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the ratio of the distance to the foci and the length of the major axis of an ellipse (how oval a shape is) - a perfect circle has an eccentricity of 0, and a straight line has an eccentricity of 1
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Most elliptical orbits
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Pluto and Mercury; although Pluto does sometimes cross into Neptune's orbit
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coma
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a spherical cloud of material surrounding the head of a comet that has a high eccentricity
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Change in axial tilt (obliquity)
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every 41,000 years, the axial tilt of the earth varies from 22.1 to 24.5 which creates a wider range of temperature in the seasons
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precession
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differences in gravitational pull create a wobble that takes about 25,725 years to change the timing of the seasons
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orbital precession
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the rotation of the earth's orbit around the sun (a wobble)
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precession of the equinoxes
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the combined axial and orbital precessions every 22,000 years which would change the timing of the seasons and make winters colder and summers warmer
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event every 10,000 years
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winter would occur during summer months and summer during winter months (winter would be from June to September)
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orbital plane
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the plane formed by the path of the earth around the sun
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inclination
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the angle between the orbital plane of the solar system and the actual orbit of an object around the sun (related to eccentricity)
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asteroid belt
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area between orbits of Mars and Jupiter with asteroids
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effect of collision with comet's tail
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this collision would not be too harmful to the earth because the tail of a comet is composed mainly of glowing gas with very little mass
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perihelion
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(January 5th - Northern Hemisphere winter) the point where the earth's axis is tilted away from the sun
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aphelion
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(July 5th - Northern Hempisphere summer) the point where the earth's axis is tilted towards the sun
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