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Question

asteroids

Answer 1

• Asteroids are either rocky or metallic objects that orbit the Sun. They are too small to considered planets but are sometimes called planetoids. • They can be anywhere from the size of a pebble up to a 1000km (620 miles) in diameter; the asteroid Ceres is an example of an asteroid that is this large. • They have been found inside Earth’s orbit and all the way out past Saturn’s orbit. Most asteroids, however, are located in the asteroid belt which exists between the orbit’s of Mars and Jupiter.

Answer 2

 Comets - small, fragile, irregular - shaped body composed of a mixture of non -volatile grains and frozen gases. ```  Their orbits are elliptical (oval) or parabolic (U -shaped). The orbit brings them in very close to the Sun and swings them far out into space, sometimes out past Pluto. ```  As comets approach the Sun, radiation from the Sun evaporates the ice and gases, creating the lone tail. The closer to the Sun, the longer the tail of the comet. The tail of the comet always faces away from the Sun because of the solar wind coming from the Sun.

Answer 3

• Meteoroids - asteroids that are on a collision course with Earth. • Meteor - streak of light created when a meteoroid strikes our atmosphere at high velocity and friction causes the chunk of space matter to burn up. • Meteorite - what is left that strikes the Earth’s surface if the meteoroid does not burn up completely. • 92.8% of all meteorites are composed of silicate (stone), and 5.7% are composed of iron and nickel; the rest are a mixture of the three materials. • Stony meteorites are the hardest to identify since they look very much like terrestrial rocks.

Answer 4

is essentially a closed system. It receives energy from the sun and returns some of this energy to space.

Answer 5

 The portion of Earth that includes the interior structure, rocks and minerals, landforms, and all physical processes on land that shape the Earth’s surface.  All the continents and ocean floor are also considered parts of the geosphere.  Scientists that study this part of earth are called geologists.

Answer 6

 The Crust is like the skin of an apple. It is very thin in comparison to the other layers of Earth.  The crust is only about 3-5 miles (8 kilometers) thick under the oceans(oceanic crust) and about 25 miles (32 kilometers) thick under the continents (continental crust).  Most of the crust is composed of eight elements namely: 1. Oxygen 5. Calcium 2. Silicon 6. Sodium 3. Aluminum 7. Potassium 4. Iron 8. Magnesium  The mantle is the solid rock and is the largest part of Earth.  Earth's mantle is a silicate rocky shell with an average thickness of 2,886 kilometers (1,793 mi).  It lies between the extremely hot core and the thin outer layer of the crust.  The mantle makes up about 84% of Earth's volume.  It is predominantly solid but in geological time it behaves as a very viscous fluid.  The outer core of the Earth is a liquid layer about 2,266 kilometers thick.  It is made of iron (Fe) and nickel (Ni).  The inner core is the Earth's innermost part and according to seismological studies, it has been believed to be primarily a solid ball with a radius of about 1220 kilometers, or 768 miles (about 70% of the Moon's radius).  It is composed of an iron–nickel alloy and some light elements.

Answer 7

``` • Just above the upper mantle and still part of the crust is the Mohorovicic discontinuity or simply Moho. • It was termed as discontinuity because the seismic waves behaved differently as they traveled through this layer. • Moho is now recognized as the transitional boundary that divides the crust and the mantle. ``` ``` Andrija Mohorovicic (1857-1936) -was an Croatian meteorologist and seismologist who suggested that there are lies a boundary between the crust and boundary and was later named as the Mohorovicic discontinuity or the Moho. ``` ``` • The Gutenberg discontinuity serves as a transitional boundary between the lower mantle and the outer core. • This boundary does not remain constant because of changes in heat flow. • When heat in mantle dissipates, the molten core gradually solidifies and shrinks, moving this boundary deeper and deeper within Earth’s core. ``` ``` Beno Gutenberg (1889-1960) -was a German seismologist who discovered the Gutenberg boundary. ``` • The Lehmann discontinuity is a transitional boundary between the inner and outer core. ``` Inge Lehmann (1888-1993) -was a Danish seismologist who in 1936, asserted that Earth’s core is not just a single molten sphere but it comes with a solid inner core based on seismic data. ```

Answer 8

 The atmosphere is the thin gaseous layer that envelopes the lithosphere.  The present atmosphere is composed of 78% nitrogen (N), 21% oxygen (O2), 0.9% argon, and trace amount of other gases.  One of the most important processes by which the heat on the Earth's surface is redistributed is through atmospheric circulation.  There is also a constant exchange of heat and moisture between the atmosphere and the hydrosphere through the hydrologic cycle.

Answer 9

 Troposphere ```  this layer is considered to be the densest among the other layers. Because temperatures drops with altitude, warm air on the surface of Earth rises readily.  Air molecules travel up and back down causing the formation of clouds and eventually rain from the moisture in the air.  Almost all weather variations occur within the troposphere.  prior to reaching the next layer above the troposphere is a thin buffer zone called the tropopause. ``` Stratosphere ```  the air in this layer has strong , steady horizontal winds which is advantageous to long distance flights.  At its upper region is the ozone layer at about 6.2 miles or about 33 000 feet above Earth’s surface which contain a high concentration of ozone.  another thin buffer zone exists before the next layer above the stratosphere and this zone is called the stratopause. ``` ```  Mesosphere  this is the layer above the stratosphere. The temperature here reaches a minimum of -90 °C and is considered to be the coldest layer.  This layer is important in protecting the Earth from planetary debris.  the thin buffer zone above the mesosphere is called the mesopause. This zone is actually the coldest region in the atmosphere. ``` Thermosphere  this layer is the hottest layer because of its absorption of highly energetic solar heat.  the lower part of the thermosphere is the ionosphere where most collision of oxygen and nitrogen particles are electrically charged by the solar wind.  Solar wind is a stream of energized, charged particles flowing from the sun.  Charged particles- are called ions, consists of protons and electrons with high kinetic energy and the high temperature of the corona.  there exists a thermopause above the thermosphere that also serves as a buffer zone which separates the

Answer 10

 About 70% of the Earth is covered with liquid water (hydrosphere) and much of it is in the form of ocean water.  Only 3% of Earth's water is fresh: two-thirds are in the form of ice, and the remaining one-third is present in streams, lakes, and groundwater.

Answer 11

1. Water could be in liquid form, not just solid and gas. 2. Water has a neutral pH. 3. Water is a good conductor of heat and energy. 4. Water has a specific heat. 5. Water is a universal solvent.

Answer 12

 Surface water may be either marine water or fresh water. Marine water has higher salt content and is found in larger bodies of water such as oceans, seas, bays. Freshwater are those in lakes, rivers, springs and falls. Has a salt lower content. It is the best source of drinking water for all organisms.  Ground water is the water found beneath Earth’s surface where there are spaces in the soil or fractures in rocks.

Answer 13

James Hutton (1726-1797) -is recognized as the founder of modern geology. He was a Scottish naturalist and farmer. Charles Darwin (1809-1882) -was an English naturalist known for the theory of evolution. Alexander Oparin (1894-1980) -was a Soviet biochemist who proposed the primordial soup theory in 1924 to explain the origin of life on Earth . ``` Stanley Miller (1930-2007) -was a Jewish- American chemist who conducted an experiment in 1952 to test the hypothesis of Oparin’s primordial theory.. ```

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