The Earth - Geography and Geology
Author: Robert W. Penry @ 2023
Our World - the Planet Earth
SECTION I – CHARACTERISTICS
The Earth is a water world. It is covered by vast body of water known as the Great Ocean. However, it is not a smooth planet. Under the water are huge canyons, mountains, plateaus, and volcanos. Sometimes these features rise above the water’s surface as land both continents and islands.
The Earth is also a world of fire. Below its surface in both water and land, lie cracks and weak spots in a layer of the earth, we call its crust. The earth is round like an orange. Its crust is like the skin of the orange. The Earth’s crust is between 18.6 and 43.5 miles thick. Below the crust lies molten rock. In weak spots in the crust, the molten area below protrudes through the crust and creates fiery protrusions, we call volcanos. These can exist in both water and land. The volcanos can sometimes erupt, spilling out molten rock, and grow larger, or explode and almost disappear.
The Earth is also a living planet. Besides the water and the land, the earth is also surrounded by a layer of gases about 60 miles thick. This layer contains oxygen, an element necessary for life. Oxygen also exists in the water. Living creatures can exist in the water, the land, and the air. In the water, we have life that can swim or float. On land, we have life that can walk or crawl. In the air, we have life that can fly. On land and water, we have life that doesn’t move at all such as flowers, grass, shellfish and coral.
The Earth uses Time, Distance, and Location. Consider this problem. The distance from Chicago to New York City is 790 miles by rail. A train leaves Chicago at 10:00 a.m. EST traveling an average speed of 55 mph enroute to New York. A train leaves New York at 10:30 a.m. EST at an average speed of 70 mph enroute to Chicago. At what location and at what time do the trains pass? (The formula is: If two trains leave x and y stations at time t1 and t2 respectively and travel with speed L and M respectively, then distanced from x, where two trains meet is = (t2 – t1) × { (product of speed) / (difference in speed) Time/Distance/Location are related. Occupancy indicates who or what is at a particular location. (Click the picture links above to read about Time, Distance, Location, or Occupancy)
Time:
Since living creatures rove across the surface of our planet, one creature, with the ability to reason. needed to understand direction and time to travel. That creature was man. Men realized that they needed to divide up the planet into recognizable areas. So, man began naming areas and features of the planet (and also names for the living creatures). Men also needed to know how long it took to travel from one point to another, so time itself needed to be defined.
Men observed that features in the sky such as the sun, moon and stars appeared to move in determined cycles.
In ancient Egypt, men invented shadow clocks (sundials) and placed 12 equally spaced marks from dawn to dark. The dark divisions were based on the observation of stars. These distances came to be known as hours and thus the 24-hour day was defined.
The Babylonians decided to break the hour into sixty minutes and the minute into sixty seconds because their number system (sexagesimal) or counting in units of 60 was used for mathematics and astronomy. They borrowed this number system from the Sumerians who developed it about 3500 BC.
This is a good start to announcing our location, but it is not accurate enough. We need to divide the degrees more. So, we divide each degree into 60 units we call minutes and then divide each minute into 60 units we call seconds, then each second is divided into 1000 units. When we travel, we often divide distance into how much time it takes to cover the distance. Since distance and time are related. minutes and seconds for distance made sense.
N 39°54’1.361” W 83°26’30.922” is where I am right now as I am typing this. That set of coordinates is the location of my house on the planet Earth – London, Ohio, United States of America, Northern Hemisphere, Western Hemisphere. It is accurate to a block of land 16 by 33 feet. Considering this is a single point on an entire planet, it is very accurate. We have GPS units that we can carry or perhaps our vehicle has GPS that can measure to an even higher level of accuracy.
