State and explain two theories that explain the origin of the earth. 7. State 3 effects of revolution of the earth.

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6. State and explain two theories that explain the origin of the earth.

1. Nebular Hypothesis: This theory suggests that the Solar System, including Earth, formed from a rotating cloud of gas and dust called a nebula. Over time, gravity caused the nebula to collapse, forming a central star (the Sun) and a surrounding disk of material. Planets then accreted from this disk through collisions and gravitational attraction of smaller particles.
2. Planetesimal Theory (or Tidal Theory): This theory, proposed by Chamberlin and Moulton, suggests that a passing star came close to the Sun, causing tidal forces that pulled material from both stars. This ejected material then condensed into small bodies called planetesimals, which eventually collided and accreted to form the planets, including Earth.

7. State 3 effects of revolution of the earth.

1. Causes the seasons: The Earth's tilt on its axis combined with its revolution around the Sun leads to different parts of the Earth receiving more direct sunlight at different times of the year, resulting in the change of seasons.
2. Varying lengths of day and night: As the Earth revolves, the angle at which the Sun's rays hit different latitudes changes, causing the duration of daylight and nighttime to vary throughout the year, especially noticeable away from the equator.
3. Changes in the apparent position of the Sun and constellations: Due to the Earth's orbital motion, the Sun appears to move across different constellations over the course of a year. This also means that different constellations are visible in the night sky at different times of the year.