Earth's Spheres: Random Facts Trivia Quiz

Answer: nickel and iron

Earth's radius measured at the equator is 6378 km, while at the poles it's 6356 km. The internal structure of our planet was discovered by analyzing the compression (P) and shear (S) waves that pass through the Earth after earthquakes. The core is the part of the planet which starts at 2900 km and runs all the way down to the center.

The core includes the outer core (2900-5000 km), a liquid molten core of nickel and iron, a transition zone (5000-5200 km) and the inner core (5200-km), a solid core made up of the same two metals.

The three parts of the core are delimited by two discontinuities, Lehmann (5000 km) and Oldham-Gutenberg (5200 km). The core's density is 8-12 g/cubic cm.

Answer: 2900 km

The mantle begins at the lower limit of the crust. It is also divided into two layers, separated by a transition zone. The lower mantle extends from the Repetti discontinuity (980 km) to the mantle-core boundary, marked by the Gutenberg discontinuity (2900 km).

It is mostly solid. The transition zone is located between the Jeffreys (410 km) and Repetti discontinuities. Above comes the upper mantle, made out of liquid molten material, with an average density of 5 g/ cubic cm.

Answer: it enables plate tectonic movements

The asthenosphere is the upper part of the mantle. This viscous and soft layer supports the earth's crust, which consists of plates with different weights. These dip into the asthenosphere more or less until they find a relatively static poise (isostatic equilibrium). Because of the fluidity and the varied temperatures, convection currents form in the asthenosphere.

These currents transfer magma between the upper and lower asthenosphere. Some of the hot magma elevated form the interior can penetrate the cracks of the crust, thus giving birth to volcanic lava. The name of this region comes from the Greek "asthenia" meaning weakness.

Answer: rock

The lithosphere is the outer layer of the earth, including the crust the uppermost layer of mantle (50-300 km thick). Unlike the asthenosphere, which flows just beneath it, the lithosphere is solid and responds to stresses in consequence. The lithosphere is fragmented into plates, whose independent movements are known as plate tectonics.

They stand behind the forming of mountain ranges and are the cause of earthquakes.

Answer: Mohorovicic

The crust is the "shell" of the planet. The border with the mantle is marked by the Mohorovicic (Moho) discontinuity. The crust is about 20-80 km thick in continental regions while only 5-10 km in oceanic regions. Its density is about 3 g/cubic cm. Depending on the predominant rocks, the structure of the crust is characterized by three different layers: basaltic (oceanic), granite(continental) and sedimentary.

The basaltic layer is found both under the continents and in the ocean floor. The granite layer is mostly found in the continents and generally not the ocean floor.

The sedimentary cover (strati-sphere) is made up of the materials proceeding from the erosion of preexisting rocks by the external agents (water, wind etc); it is 0-km thick.

The sedimentary rocks make up only 5% of the crust's total volume, but they cover 75% of the earth's surface.

Answer: they are all components of the hydrosphere

Most of the earth's surface is covered by water. But water also exists in the atmosphere (vapors), on land (rivers, lakes and glaciers), in the soil and underground. All of these components form the hydrosphere. Water can reach heights of 10-15 km in the atmosphere, can go 10-20 km deep in the crust and may be found in the composition of rocks 50 km deep. Salty water makes up 96.5% of the hydrosphere.

The remaining 3.5% of fresh water is then divided like so: 77.2% in glaciers and ice caps, 22.4 % in the soil and underground water, 0.35% in lakes and swamps, 0.04% in the atmosphere and only 0.01% in rivers.

The most important process taking place in the hydrosphere is the hydrological cycle. The solar heat evaporates the water from the ocean, which is then carried by winds toward the land, where it falls as rainfall.

This is then collected by rivers, which carry it back to the ocean.

Answer: minerals

The biosphere consists of all the living things on our planet. About 1.5 million distinct species have been identified so far, but it's estimated that the actual figure can be a few times bigger than this. Most living organisms are to be found at the interference zones of the geospheres or in their close vicinity. Generally, animals are wider spread than plants, populating the whole surface of the earth and reaching great depths in the oceans.

Answer: 99%

The atmosphere - Earth's gaseous cover - is the outermost "sphere", wrapping all the others as a continuous layer. Its existence is due to the interaction of various factors like the earth's attraction force and chemical composition. The outer limit of the atmosphere is about 10 km (35 km by other measurements) hence its density - calculated based of the frequency of hydrogen atoms - becomes equal with that of interplanetary space. Earth's influence is to be felt in the atmosphere up to about 100 000 km.

Answer: composition

The atmosphere is divided into regions according to composition or temperature. The first criterion divides it into homosphere and heterosphere while the second delimits five regions: troposphere, stratosphere, mesosphere, ionosphere and exosphere.

Answer: 80 km

The heterosphere is very different in composition from the homosphere. The homosphere - "same (composition)" sphere - concentrates 80% of the air in the atmosphere. The gases are present here in their molecular form so the homosphere is relatively homogeneous regarding the chemical composition, which is basically the same throughout the whole km above sea level. Above this is the heterosphere - "different" (composition) sphere.

The gases exist in their atomic form and do not mix much. They are also layered based on their molecular weights (the lighter the gas the higher is to be found in the heterosphere). Solar wind and radiation cause particles in the heterosphere to be ionized.

Answer: It is located about 50 to 85 km above the Earth's surface

Most of the atmosphere mass is concentrated in the close vicinity of the Earth's surface. It was measured that the atmosphere's total mass (half of it located just in the 5 km above sea level) is just a million part of the Earth's mass.
Due to earth's centrifugal force, the troposphere takes the planet's shape, becoming bulged at the Equator (reaching heights of 16-18 km) and slightly flattened at the poles (reaching a height of 6 km). The troposphere is delimited from the stratosphere by the tropopause, situated at an average of 12 km above sea level.
The troposphere is the region where most weather phenomena occur. The troposphere is divided into six zonal flow regions, which are responsible for atmospheric circulation. In the troposphere, the temperature drops with height, with an average value of 6.4 degrees Celsius for each km; thus, the temperature recorded at the tropopause level is about -60 degrees Celsius.
The word troposphere comes from the Greek "tropos" meaning turning or mixing.

Answer: infrared radiations

The stratosphere is situated above the troposphere and extends up to 50 km - marked by the stratopause. The temperature rises from -60 to -4 degrees Celsius because of the ozone layer (between 20-40 km) which absorbs the solar ultraviolet radiation and reflects the cosmic radiation.

Answer: meteors

The mesosphere stretches between the stratopause (50 km) and the mesopause (80 km) and is characterized by a new temperature decrease with altitude, dropping from -4 to -83 degrees Celsius. Meteors melt or vaporize in the mesosphere as they collide with the gas particles within this layer.

Another feature of the mesosphere are the rare noctilucent clouds, the highest clouds in the atmosphere. They are composed of water ice and seem to be a relatively recent atmospheric phenomenon.

Answer: Ionosphere

Also known as the ionosphere because of the ionized particles that prevail here, the thermosphere is situated between 80 and 500-1000 km. The temperature rises again from the inferior part (-83 degrees) toward the superior part, reaching up to 1100-1600 degrees.

The thermosphere includes several layers (D, E, F, G) which play an important role in absorbing solar radiation and reflecting the radio waves emitted from Earth. Another phenomenon which occurs within this region are the auroras, which are caused by the interaction of high energy particles, carried by solar winds, with the neutral atoms from the thermosphere.

Answer: satellites orbit in this layer

The exosphere the exterior atmospheric layer, coming in contact with the outer space. The atmosphere is very rarefied at this level.
There are two radiation belts around the Earth (at heights of 3000-4000 km and 15000-20000 km) formed by solar electrical particles, captured by the planet's magnetic field. The cosmic space influenced by the Earth's magnetic field (up to 100 000 km) is called magnetosphere.
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