Group V Day And Night

Earth,Sunrise,sunset and the cycle of the day (aka. the diurnal cycle) is a simple factor of life. Seasonal changes can cause slight changes in how long the day or night is but by just a few hours, but in some regions of the world the cycle is completely different, these places are the earths poles where at some times of the year the sun does not set but at other times nights can last for several days.

Earth's rotation occurs from east to west, which is why the sun always to be rising from the east horizon and setting in the west. If you viewed the world from above looking down at the northern pole region the planet would seem to be rotating anti-clockwise but viewing from the south pole it would appear to be clockwise. The earth rotates about once every 24 hours with respect to the sun and once every 23 hours 56 minutes and 4 seconds with respect to the stars. Its central axis is aliened with 2 stars, the northern axis points outwards towards Polaris hence being called the northern star while the southern axis points towards Sigma Octanis. Due to the earths axail tilt day and night are not split evenly. If the earths axis were perpendicular to its orbital plane around the sun day and night would both be 12 hours every day and there would be no seasonal changes.Instead one axis faces the sun leaving tyhe other pointed away, the hemisphere pointing towards the sun will therefore causes warmer weather and longer days.

The Summer Solstice takes place between June the 20th and 22nd in the Northern hemisphere and the between the 20th and 23rd of December in the Southern hemisphere, the winter solstice occurs at the same time but reverse.

A feature in the day and night cycle is the moon, stars and other celestial bodies, although we don't always see the moon at night. On certain days the moon is well-positioned between the sun and earth making it visible in the day, while other planets and stars are only visible at night.

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