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The Earth is a sphere that is constantly moving. It rotates on its axis, revolves around the Sun, and orbits the Milky Way galaxy. These movements cause a variety of phenomena on Earth, including day and night, the seasons, and tides.
Rotation is the Earth’s movement around its own axis. The Earth’s axis is an imaginary line that runs through the North and South Poles. The Earth takes 24 hours to rotate once on its axis. This is why we have day and night. The side of the Earth that is facing the Sun is in daylight, while the side that is facing away from the Sun is in darkness.
Revolution is the Earth’s movement around the Sun. The Earth takes 365.25 days to revolve around the Sun. This is why we have a calendar year with 365 days, plus an extra day every four years (leap year). The Earth’s orbit around the Sun is not a perfect circle. It is slightly elliptical, which means that the Earth’s distance from the Sun varies throughout the year.
Precession is the Earth’s slow wobble as it rotates on its axis. This wobble takes about 26,000 years to complete. Precession is caused by the gravitational pull of the Moon and the Sun on the Earth’s equatorial bulge.
Nutation is a small, irregular wobble in the Earth’s axis that occurs in addition to precession. Nutation is caused by the gravitational pull of the Moon and the Sun on the Earth’s non-spherical shape.
Axial tilt is the angle between the Earth’s axis and its orbital plane. The Earth’s axis is tilted at an angle of 23.5 degrees. This tilt is what causes the seasons.
Orbital eccentricity is the measure of how elliptical an orbit is. The Earth’s orbit is slightly elliptical, with an eccentricity of 0.0167. This means that the Earth’s distance from the Sun varies by about 3 million miles throughout the year.
Orbital inclination is the angle between an object’s orbital plane and the plane of the ecliptic. The Earth’s orbital inclination is 0 degrees. This means that the Earth’s orbit is in the same plane as the Sun’s equator.
Orbital period is the time it takes for an object to complete one orbit around another object. The Earth’s orbital period around the Sun is 365.25 days.
Orbital speed is the speed at which an object orbits another object. The Earth’s orbital speed around the Sun is about 18.5 miles per second.
Orbital plane is the plane in which an object orbits another object. The Earth’s orbital plane is the plane of the ecliptic.
Equinoxes are the two times of the year when the Sun crosses the equator. The vernal equinox occurs on March 20 or 21, and the autumnal equinox occurs on September 22 or 23. The equinoxes mark the beginning of spring and fall, respectively.
Solstices are the two times of the year when the Sun is at its highest or lowest point in the sky. The summer solstice occurs on June 20 or 21, and the winter solstice occurs on December 21 or 22. The solstices mark the beginning of summer and winter, respectively.
Seasons are the four periods of the year that are characterized by different weather patterns. The seasons are caused by the Earth’s tilt on its axis and its orbit around the Sun. The Earth’s tilt causes the Sun’s rays to hit different parts of the Earth more directly at different times of the year. This causes the temperature to vary throughout the year.
Tides are the rise and fall of the sea level caused by the gravitational pull of the Moon and the Sun. The tides are highest when the Moon is closest to the Earth (perigee) and lowest when the Moon is farthest from the Earth (apogee).
Lunar phases are the different shapes of the Moon that we see as it orbits the Earth. The Moon’s phases are caused by the changing angle between the Sun, the Moon, and the Earth. The Moon goes through a complete cycle of phases in about 29.5 days.
Eclipses are astronomical events that occur when one celestial body passes in front of another. There are three types of eclipses: solar eclipses, lunar eclipses, and transits. Solar eclipses occur when the Moon passes between the Earth and the Sun. Lunar eclipses occur when the Earth passes between the Sun and the Moon. Transits occur when a planet passes in front of the Sun.
* Rotation: The spinning of a planet or other celestial body on its axis.
* Revolution: The movement of a planet or other celestial body around another object in space.
* Precession: The slow, steady change in the orientation of an object’s axis of rotation.
* Nutation: The small, irregular wobble in the Earth’s axis of rotation.
* Axial tilt: The angle between a planet’s axis of rotation and its orbital plane.
* Orbital eccentricity: The deviation of an orbit from a perfect circle.
* Orbital inclination: The angle between a planet’s orbital plane and the plane of the ecliptic.
* Orbital period: The time it takes for a planet to complete one orbit around the Sun.
* Orbital speed: The speed at which a planet moves in its orbit around the Sun.
* Orbital plane: The plane in which a planet orbits the Sun.
* Equinoxes: The two times of year when the Sun crosses the equator, on March 20 or 21 and September 22 or 23.
* Solstices: The two times of year when the Sun reaches its highest or lowest point in the sky, on June 21 or 22 and December 21 or 22.
* Seasons: The four periods of the year (spring, summer, autumn, and winter) that are caused by the Earth’s tilt on its axis and its orbit around the Sun.
* Tides: The rise and fall of the sea level caused by the gravitational pull of the Moon and the Sun.
* Lunar phases: The different shapes of the Moon as seen from Earth, caused by the Moon’s orbit around the Earth.
* Eclipses: An astronomical event that occurs when one celestial body passes in front of another.
1. The Earth rotates on its axis once every:
(a) 24 hours
(b) 365 days
(CC) 1 year
(d) 1 month
The Earth revolves around the Sun once every:
(a) 24 hours
(b) 365 days
(c) 1 year
(d) 1 monthThe Earth’s axis is tilted at an angle of:
(a) 23.5 degrees
(b) 45 degrees
(c) 60 degrees
(d) 90 degreesThe Earth’s orbit around the Sun is not a perfect circle. It is slightly elliptical. This means that the Earth’s distance from the Sun varies throughout the year. The Earth’s distance from the Sun is closest at:
(a) perihelion
(b) aphelion
(c) equinox
(d) solsticeThe Earth’s orbit around the Sun takes 365.2422 days to complete. This means that we have to add an extra day to our calendar every four years. This extra day is called:
(a) leap day
(b) leap year
(c) leap month
(d) leap centuryThe Earth’s axis is tilted relative to its orbital plane. This tilt causes the Earth to experience different seasons throughout the year. The Northern Hemisphere experiences summer when the Northern Hemisphere is tilted towards the Sun. This occurs during the months of:
(a) June, July, and August
(b) December, January, and February
(c) March, April, and May
(d) September, October, and NovemberThe Earth’s tides are caused by the gravitational pull of the Moon and the Sun. The Moon’s gravitational pull is stronger than the Sun’s gravitational pull, so the Moon has a greater effect on the Earth’s tides. The highest tides occur when the Moon is full or new. This is because the Moon is directly overhead or directly below the Earth at these times.
The Moon goes through a cycle of phases as it orbits the Earth. The phases of the Moon are: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent.
A lunar eclipse occurs when the Moon passes through the Earth’s shadow. This can only happen when the Sun, Earth, and Moon are in a straight line. A solar eclipse occurs when the Moon passes between the Earth and the Sun. This can only happen when the Moon is full.
The Earth’s rotation causes day and night. The Earth’s revolution around the Sun causes the seasons. The Earth’s tilt causes the seasons to be different in the Northern and Southern Hemispheres. The Earth’s orbit around the Sun is not a perfect circle, which causes the Earth’s distance from the Sun to vary throughout the year. This variation in distance causes the seasons to be slightly different in different years.