Earth's Oceans and Deserts Help (page 3)
The surface of Earth is largely covered by mineral-rich oceans of water. The largest of these, if seen from a certain vantage point in space, covers almost half the planet. This is the Pacific Ocean ; it was given this name by some Earth dweller who saw it at one of its more peaceful moments. ( Pacific means “peaceful” or “tranquil.”) However, this ocean is not always calm. Revolving storms, called hurricanes in the eastern Pacific and typhoons in the western Pacific, churn the waters and transport excess heat from the tropics toward the polar regions.
Hurricanes also occur in the Atlantic Ocean and in the Indian Ocean. The storms form at lower latitudes, and they almost always work their way either onto a land mass, where they dissipate, or toward cold water, where they expire from lack of heat to sustain their winds. Occasionally, one of these storms strikes a human-made anthill. Some of the planet’s most elaborate anthills are built directly in known hurricane tracks. I wonder why the human Earth dwellers construct so many of their communities in such places?
The waters flow in slow currents around and around the oceanic basins, generally clockwise in the northern hemisphere and counterclockwise in the southern. This gives rise to warm ocean currents along the eastern shores of the continents and cold currents along the western shores. This has a profound influence on the distribution and movement of weather systems in the planet’s atmosphere. When something happens to upset the regularity of these currents, the climate changes over much of the planet. These cycles are natural and have been taking place for millions of human-defined years. However, almost every time such a cycle recurs, especially the sort known as El Niño where the eastern equatorial Pacific waters switch from cold to warm, the humans call the resulting weather a disaster .
The oceans are critical to the balance of life on Earth. They are like the lungs and blood of a living organism. Tiny life forms called plankton live in the oceans; these are eaten by larger life forms such as the fish . Fish are a favored food among the two-legged humans. However, humans dump toxic chemicals and hydrocarbon dregs into the oceans, where they work their way into fish and then into their brothers’ and sisters’ bodies, causing terrible illnesses and suffering. Humans know about this. We have heard them talk about it in their electromagnetic broadcasts. Why do they continue to knowingly harm themselves in this way?
The Land Masses
The oceans tend to heat up and cool down slowly. They hold heat energy. Land masses are just the opposite. They heat up and cool down rapidly. This contrast, along with the oceanic currents and the prevailing differences in temperature between the tropics and the polar regions, creates the climate and weather variations on this third planet from the star we call Sol. Earth is the only planet with weather varied enough to motivate the evolution of life but not so violent or hostile as to exterminate such life before it gets a chance to evolve.
In some places water accumulates in the atmosphere and then precipitates onto land masses in great amounts. This can happen either as liquid water, in which case it is called rain , or as frozen water, known as snow . There are other, less common forms of precipitation, such as hail , but these do not contribute much to the overall ecological system of the Earth.
In the regions where precipitation is abundant and mostly liquid, forests of tall plants grow. Some of these plants are cut down and used as materials by the two-legged humans in the construction of dwellings in their anthills. It is amazing how many different geometries have been invented for these dwellings! The plants, called trees , make ideal building material, and they can be replenished by intelligent management. Unfortunately, in some regions of the planet no attempts are made to replenish the supply of trees. Humans obviously know the supply of trees is not infinite and eventually will be depleted if balance is not maintained. Do they not care about their own future?
Layers Of The Atmosphere
The Earth’s atmosphere is 78 percent nitrogen at the surface and 21 percent oxygen. The remaining 1 percent consists of argon, carbon dioxide, ozone, and water vapor. The temperature of the atmosphere varies considerably; it can rise to about 55°C (130°F), or plunge to around –80°C (–112°F).
The lowest layer of the atmosphere, rising from the surface to approximately 16 km (10 mi) of altitude, is the troposphere . This is where all weather occurs; most of the clouds are found here. In the upper parts of the troposphere, high-speed rivers of air travel around the planet in a generally west-to-east direction. There can be two or three of these rivers in the northern hemisphere and two or three in the southern hemisphere. The strongest of these rivers, called jet streams , carry high- and low-pressure systems from west to east at temperate latitudes, primarily between 30°N and 60°N, and between 30°S and 60°S.
Above the troposphere lies the stratosphere , extending up to approximately 50 km (30 mi) of altitude. Near the upper reaches of this level, ultraviolet radiation from the Sun causes oxygen atoms to group together into triplets (O 3 ) rather than in pairs (O 2 ), as is the case nearer the surface. An oxygen triplet is a molecule known as ozone . This gas has the unique property of being opaque to ultraviolet rays. Thus oxygen atoms form a self-regulating mechanism that keeps the Earth’s surface from receiving too much ultraviolet from the Sun. Certain gases are produced by industrial processes carried on by the two-legged humans; these gases rise into the stratosphere and cause the ozone molecules to break apart into their individual atoms. This makes the upper stratosphere more transparent to ultraviolet than it would be if nature had its way. Some humans have demonstrated that if this process continues, it could have an adverse effect on all life on the planet. Other humans do not believe this and continue to produce these potentially dangerous industrial by-products.
Above the stratosphere lies the mesosphere , extending from 50 km (30 mi) to an altitude of 80 km (50 mi). In this layer, ultraviolet radiation from the Sun causes electrons to be stripped away from atoms of atmospheric gas. The result is that the mesosphere contains a large proportion of ions. This occurs in a layer that communications engineers call the D layer of the ionosphere .
Above the mesosphere lies the highest layer of the Earth’s atmosphere, known as the thermosphere . It extends from 80 km (50 mi) up to more than 600 km (370 mi) of altitude. This layer gets its name from the fact that the temperature is extremely high, even hotter than at the surface of Venus or Mercury. However, these high temperatures do not have the devastating effects they would have if they existed at the surface because the atmosphere at this level is so rarefied. Ionization takes place at three levels within the thermosphere, called the ionospheric E layer, F1 layer , and F2 layer . Sometimes, particularly at night, the F1 and F2 layers merge together near the altitude of the F2 layer; the resulting layer is called the F layer . Figure 8-4 is a diagram of the Earth’s atmosphere showing the various layers and the ionized regions.
Excerpt From A First Officer’s Journal
I have just received a stern warning from the authorities back home on Epsilon Eridani 2. Their mandates are as follows:
- Our Earth landing assignments have been reduced from 10 to 3.
- We are not to land within 50 km (30 mi) of any place known to be populated, even sparsely, with the two-legged life forms that call themselves Homo sapiens .
- We are to keep our radar and optical cloaking devices activated at all times.
- If we accidentally happen to encounter any Homo sapiens , we are to explain to them that we are part of a “Hollywood movie set” and then ask them to leave.
This seems to defeat the most important part of our mission: to find out exactly what makes Homo sapiens behave as they do. However, I can’t fight the bureaucracy of Epsilon Eridani 2! I will have to be content with looking at these creatures, whom I have decided to call bipedal ants , through telescopes while in orbit and analyzing their migration patterns with radar and computer programs.
North Atlantic Ocean
We descend into the middle of the Azores-Bermuda high-pressure system in the North Atlantic Ocean, hoping to find calm conditions. It is the part of the Earth year that the bipedal ants call April , when hurricanes are unknown in this part of the planet. Nevertheless, when we reach the ocean, we find that there are huge waves on the surface. The waves come from the north, and we recall that storms can track across the North Atlantic at any time of the year.
In the northern-hemispheric spring, storms follow the jet stream, coming off the North American continent near the mouth of the St. Lawrence Seaway and taking paths at high latitudes toward Europe. Our meteorology expert on the main ship confirms that one of these storms is passing near Iceland, and it is responsible for generating the waves. We are surprised that waves can travel so far and still be so large, but the main-ship radar telescope indicates that their effects reach all the way south to Antarctica.
The atmosphere is perfectly calm; there is no wind as we land and observe a temperature of 23°C (73°F) at high noon. We float like a cork on the swells, which measure 11 m (36 ft) from crest to trough. The surface of the water is smooth except for these sine-wave-shaped swells, a most remarkable phenomenon.
By sunset, the temperature of the atmosphere has hardly changed; it is 22°C (72°F). At midnight, the atmospheric temperature has gone down to 20°C (68°F), and just before sunrise on the day after our landing, it is at its minimum of 19°C (66°F). This small temperature variation between day and night confirms our theory that the oceans keep the lower atmospheric temperature relatively stable. The water temperature is measured at 20°C (68°F).
We remain on the surface of the ocean, examining the abundant life in the water, for exactly one solar day. We see no signs of the bipedal ants, either on the surface of the ocean or in the atmosphere above it, even though we have been told that aircraft will fly overhead and one of them will descend to investigate us. We are relieved when we lift off at noon, exactly 24 Earth hours after we landed. Because of the violent and continuous motion induced by the waves, I have lost 2.5 kilograms (kg) of body weight. This is 5.5 pounds (lb) in the Earth’s gravitation. It has taken place because I have been unable to eat or drink anything for the past 24 Earth hours without having it come back up. Many bipedal ants suffer this same malady when they are first introduced to oceanic travel; they call it sea-sickness .
Antarctica is a huge ice cap centered at the Earth’s south geographic pole. All the continental land mass, with the exception of a small peninsula that reaches northward toward South America, is covered by water ice throughout the year. This ice extends offshore into the sea for a considerable distance in some places.
It is April, early autumn in the Earth’s southern hemisphere. We are concerned about the possibility of high winds upsetting our craft and low temperatures straining our life-support systems if we land on the ice cap itself. We therefore decide to land at the tip of the Antarctic Peninsula that juts northward. This is not only the northernmost point on the continent, but it is largely surrounded by ocean, which, we hope, would keep temperatures from dropping too low.
As we approach the surface, it becomes apparent that this landing is going to make our North Atlantic excursion seem tame by comparison. We see snow (small flakes of water ice) rushing horizontally along the surface, driven by a wind of hurricane force. When we land, a gust almost knocks our craft off its landing gear and onto its side. Despite this wind, small black-and-white bipedal animals, looking like birds but acting more like bipedal ant children, run around, seemingly unaffected by the tempest. They jump in and out of the water, and some of them waddle up to our vessel and then stand there watching us, as if they expect us to come out and play in the water with them. We reject this option. The temperature is –37°C (–35°F).
The gale increases steadily. We decide to return to the main ship before the storm plucks our landing vessel up and rolls it across the bleak, rocky terrain. It never crosses our minds to venture outside into these conditions, which seem, despite the hospitable atmosphere, more severe than the worst storms we have ever seen on Sol 4 (Mars). Thus we blast off, struggling to maintain stability, and we are relieved when we reach the stratosphere and spot our main ship, the Dragon , as a bright dot in the sky.
The only characteristics that the Sahara Desert shares with Antarctica are wind and dryness. In every other respect the two places are so different that it is hard to believe that they exist on the same planet.
We land at high noon on sandy, rolling terrain that looks like certain parts of Mars but with fewer rocks and boulders. The atmospheric temperature is 49°C (120°F) and rising. There is little wind, but the large dunes give away the fact that strong winds blow regularly in the area. The sky is hazy blue, pinkish near the horizon, again reminiscent of Mars.
By late afternoon, the temperature reaches a peak of 53°C (127°F), which we on Epsilon Eridani 2 consider ideal. The Sun, which has passed the zenith, sets in a ruddy cloud that again reminds us of home. The temperature quickly drops, and a brisk wind comes up. By midnight the temperature is 17°C (63°F), and in the predawn hours it drops to 14°C (57°F). We attribute this large day-night temperature differential to the high altitude of the site we have selected and to the fact that sand does not retain heat very well.
Just before liftoff at sunrise, we see tracks in the sand that appear to have been made by four-legged animals. However, no life is in sight, and we have been strictly warned to avoid the risk of contact with the bipedal ants. According to our Earth sociology books, it is not unknown in the Sahara Desert to see bipedal ants riding four-legged, long-necked animals.
As we blast off, in the distance I see objects moving slowly across the sand. I get my hand telescope and take a magnified look. There is a scene out of a picture book I saw about Earth when I was a child: Four Homo sapiens , each riding a four-legged, long-necked, hump-backed animal! I am astounded. Who would have guessed that the bipedal ants of the planet Earth have progressed to such a level of sophistication that they employ nonmechanized, nonpolluting modes of transportation? I expected, if I saw any life at all in the Sahara, to see them riding crazily around in four-wheeled, internal-combustion-propelled vehicles, tearing up what few plants manage to survive in that environment. Maybe the bipedal ants are not as barbaric as we have supposed.
From what we have seen of Earth, it is a stormy, desolate place. We deliberately chose regions where intelligent life would not likely be found. However, based on these observations, it is hard to imagine how any place on Earth could allow humans to build a civilization without great struggle and sacrifice. The bipedal ants must cooperate closely to build and maintain their anthills. But how can we know what these anthills actually are, what they do, and why they exist until we can visit one of them?
We only looked at three places on Earth, and this is not a sufficient sampling to know the nature of the planet as a whole. Perhaps there are fields of green plants, or undamaged forests, or snowy mountains with small settlements where the bipedal ants can revel in their surroundings and take time to enjoy the art of living. Maybe there are clean lakes and rivers and windy, empty prairies with small individual dwellings separated by enough distance so their occupants do not become mentally and physically deranged. We have heard rumors of such places, and our telescopic observations indicate that they might exist. For now, however, we must content ourselves to visit only desolate regions. We have been told by our security agencies that were these bipedal ants to encounter us, they might think we had come to invade them and react with violence. Even if they did not fear us, they might capture and analyze us, as if we were created by the Cosmos for no other purpose than to arouse and then satisfy their curiosity.
Practice problems of this concept can be found at: The Planet Earth Practice Problems
Add your own comment
Today on Education.com
WORKBOOKSMay Workbooks are Here!
ACTIVITIESGet Outside! 10 Playful Activities
- Kindergarten Sight Words List
- The Five Warning Signs of Asperger's Syndrome
- What Makes a School Effective?
- Child Development Theories
- Why is Play Important? Social and Emotional Development, Physical Development, Creative Development
- 10 Fun Activities for Children with Autism
- Bullying in Schools
- Test Problems: Seven Reasons Why Standardized Tests Are Not Working
- Should Your Child Be Held Back a Grade? Know Your Rights
- First Grade Sight Words List