Facts ABOUT OUR Earth
Earth’s circumference at the equator is roughly 40 076592 km. But ‘only’ close to 40 009 km if we measure the circumference of the pole to pole. The poles are too flat, for our Earth to be a perfect globe. This is due to centrifugal force, the water cycle, erosion of various kinds, etc. a natural phenomena.
Exercise: If you take a rope and measure half the earth diameter. In other words, If you take 12 756 km divided by 2 and allows 10 km be equal to 1 cm on the rope, you get a rope that is approximately 6 meter and 37.8 cm long. Take your class and the to the school yard, a parking, a lawn, etc, and ask one of the pupils to hold one of the ends while you turn a circle using the rope as’ pass’. The circle you got represents the earth.
To understand the relationships between the earth’s size and our highest mountains and deepest ocean sinks, check in maps to learn the height of Mount Everest. 8 848 meter over sea. On your circle-line Mount Everest corresponds with a bulging of less than 1 cm. Make a mark. Look up Mariner-grave, the world’s deepest point in Earth’s crust. 10 911 meters. In other words, no more than 1 cm INWARD BEND from your circle. You then see what a small part of the earth as we humans have been on or below surface.
Earth’s tilt, rotation, etc.: The gradient, oblicvitety, varies relative to the Earth’s direction of rotation between 22.1 and 24.5 degrees (do not forget that a circle has 360 degrees) This variation is relatively regular and recurring every 41 000 year. We have currently a decreasing angle.
Our Earth wobbles. In other words, in addition to the Earth’s axis inclination varies over time. The cycle is 41,000 years. As do the axis vary relatively the sun and the second due to the earth just like a gyrate-whirl’s peak ‘shake’ when the speed slow down or increase. This later wobbling of the earth has a cycle of 26,000 years.
Pangea: Once long ago all continents coherent. The only continent we call Pangea. When it was broken up into tectonic plates that moved out of each other while they ‘floated’ in the ultimate layer under the ‘ground’ in our seas. Sometimes they glide over / under one or the other of the plates. Sometimes the tectonic plates collide with other plates. Sometimes they revert from other tectonic plate/-s. That was how our mountain ranges occurred as volcanoes, earthquakes, landslides, etc. occurs and occurred. In the case of landslides, there are several other conditions that affect more than the tectonic plate movements. However, these must also be included in all calculations.
Exercise: If you take a book and your friend takes another and you put your opposite one another and keep the books about as high, so happens one of the following phenomenon when you order them against each other:
* They collide and fold the two together
* The collisions and the pressure makes one or the other book move backwards away or only one of the books to be ‘pressed in one end’
* They collide and slide above and below each other.
Note that these ‘effects’ is the same as when tectonic plates float around, gnaw on or collide with each other, as earthquakes, volcanic eruptions, etc. For a long period of time, several million years this happened to form our mountains as they are, folds ups land etc. All these facts must be taken into account when calculating the earth’s climate.
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