On earth, the regolith is typically called soil and is made from natural processes such as the weathering of rocks. The soil in this case is vital to the survival of the organisms residing in the planet because it is where plants grow and where human beings build. In the case of the moon however and other objects in outer space that have no known signs of life on them, the regolith serves no other known function except to reflect light from the surface. The regolith from these celestial bodies comes mostly from the debris left over from impacts with meteors or asteroids. Because most of these bodies do not have an atmosphere surrounding them, the impact is often very hard and even small meteorites can cause damage or leave debris.

The moon’s regolith in particular is called lunar regolith and was found to be around 20 meters only at its thickest portions. The composition is mainly rocks and minerals along with glass particles from impacts with asteroids. A famous photo of the lunar regolith was taken during the Apollo 11 mission and showcases the footprint of renowned astronaut Neil Armstrong.

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It is generally known as zero degrees longitude or vertical line of reference in the world map. It was established through scientific intervention and conventions. Throughout time, the prime meridian has taken different places and exact locations. The established and modern prime meridian is now based in the royal observatory in Greenwich, a part of the legal territories of England, in the year 1884.

The modern and current zero degrees meridian, which is based on the Royal Observatory, in Greenwich, is the common referent point in navigation, either by air, or sea. It was chosen as the official prime meridian through the means of an international convention through the efforts of the then United States President Chester Arthur, with the help of 25 delegates from various nations. At those times, over two-thirds of the world has made Greenwich as the point of reference for the prime meridian. It was only the nation of France who abstained and did not vote for the said convention’s beliefs. Since then, France still used Paris as the point of navigation for more decades.

As additional information, the Royal Observatory, where the prime meridian is based on, was established by a certain Sir George Airy in the year 1851. It is now converted as a museum and at night, it beams a light northward through a laser, to mark the prime meridian.

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The upper portion of the Earth’s atmosphere is ionized with electrons liberated by the ultraviolet light of the Sun from neutral atmospheric particles, resulting into a gas now known as plasma, which is composed of both positive and negatively charged particles.

The positively charged particles are known as ions, while the negatively charged ones are termed electrons. Electrons are very low in mass, but tend to have high levels of energy. For this reason, the Earth’s gravity soon loses hold on them and they begin to gradually escape, leaving the ions to form a growing net of positive electric charge in the ionosphere while forming their own region of negatively charged space right above it. This negatively charged space will then keep the wayward electrons from moving any further from the Earth’s atmosphere.

The electrons retain their energy, and eventually attract the remaining lighter ions of hydrogen, helium and oxygen to leave the ionosphere as well. These camaraderie of escaping particles will then build up until a balance is achieved wherein there is as much plasma that flows into the ionosphere as there is that flows without. This process of exchange between particles forms the colder region of plasma known as the plasmasphere.

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Parallax provides astronomers with a simple method of calculating the distance of many celestial objects. As the Earth revolves around the Sun, celestial objects seem to be located at different positions when observed month after month. When a star is observed during June and December, observers can make use of two different viewpoints or lines of sight to the star to measure the distance. These two lines of sight intersect at the star being observed, forming an angle and half of this angle is the parallax. Typically, the distance is measured in parsecs by getting the inverse of the observed parallax measured in arc seconds.

There are different kinds of parallax, namely, stellar, solar, lunar, diurnal, and dynamic or moving cluster. It is important to keep in mind that parallax decreases with distance and can only be used to measure celestial objects at a maximum distance of 100 parsecs. The use of this concept in astronomy is extended with much precision through the use of the Hipparcos satellite.

Geometric Technique – Parallax

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The angle between a certain rotational axis of an object and the specific perpendicular line in regards to the object’s orbital plane is better known as its obliquity. In the solar system, the axial tilt of the earth is known formally as the obliquity of the ecliptic, since the name of the planet’s orbital plane is called the ecliptic plane. In formulas, it is represented by the Greek Character “Ε” or epsilon.

Apart from this, a planet’s axial tilt causes the seasons like spring or winter. This is due to the change of orientation of a planet’s obliquity, though the actual angular degree of tilt does not change, and the rotation moves until it reaches 360 degrees or one complete revolution. Thus, specifying which season it is now.

The planet earth has an approximate axial tile of 23.4 degrees. The axis stays tilted in the direction pointing to the stars for the entire year. This implies that a certain hemisphere — or half of the earth is in the direction towards the sun, half a year or half an orbit later, the other half will be now in the sun’s direction. Also, the current hemisphere that is facing the sun tends to have longer hours of sunlight.

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Are we really alone? According to the latest study, most people in the United States (more than 60% of the study) believe in extraterrestrial life. The universe is just too big for Earth to be the sole planet to support life. In fact, we can look to

Astrobiology, a study of possible life outside Earth, is an authentic and formalized field of science. NASA has funded programs to find extraterrestrial life in the universe. So far, the science has still a lot to learn and discover, and we can only speculate for now.

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Visualize the Earth as a see through sphere. Looking through the Earth one may observe an equatorial plane, with a middle point, or center of the sphere or Earth. In order to indicate the Latitude of any point on the top of the Earth, you can draw a line from the center of the sphere to the point of interest.

Thus, the angle of the point with respect to the equator is the Latitude. North of the equator, the latitude is positive, south of the equator, the latitude is negative. Thus, it is because of this angle, along with the longitude, that reading the map has become easier and more effective to use.

No longer are the days in which maps would roughly present distances based on mere perception, and not clear measurement. With the Longitude and Latitude, one will be able to specifically pinpoint with only slight error a certain point on Earth. This has been a helpful yet innovative tool over the years.

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If a body is rigid or the complete opposite – flimsy, tidal forces can tear the body in half. However, the Earth is an elastic sphere and the tidal force from the moon, in a way, distorts its shape although the mass or volume is not affected at all. Bulges' indicate this change in shape — an indication of the changes in the ocean levels due to tides, specifically.

The moon pulls on the planet as a whole, although its effect on solid Earth is only minimal – a few centimeters. It has more effect on the atmosphere and the hydrosphere. The oceans get attracted to the moon, causing high tides. However, it is noticeable that the nearer oceans are pulled more than the father oceans located at the side facing away wherever the moon is.

Tidal force also has a more general usage in astronomy, referring to the phenomenon where a body is subject to the gravitational force of a second body, while being subject to the gravitational force of a third body simultaneously, as in the case of the moon being primarily influenced by the Earth's gravity (due to its proximity) while being affected by the sun's gravitational pull as well.

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Volatiles are chemical elements and compounds that have small boiling points and are found or connected to the atmosphere and crust of both a moon and a planet. Elements such as hydrogen, nitrogen, carbon dioxide, ammonia, and methane are types of volatiles. Water is also a perfect example as well as other compounds of hydrogen, oxygen, nitrogen, silver, carbon and sulfur dioxide.

As one looks closely to the crust of both the moon and the earth, he will find these elements in huge extents. Those volatiles that have very low melting points are classified glasses such as helium and hydrogen. The volatiles that have more than 100k melting points are called asices.

The moon is said to have a minimum of volatiles because its crust has oxygen but small amounts of nitrogen, carbon and hydrogen. Scientists made a recent discovery when they studied the components of silver found in Earth rocks and meteorites. With their findings they were able to make a calculation regarding the creation of Earth. They found out that when the Earth was created, volatiles such as water and other major ones may have been present in its crust and atmosphere, therefore refuting the theory that it was comets that gave these volatiles.

On the other hand, elements that have high boiling points are called refractory elements and are composed of aluminum, titanium, calcium, uranium, and other elements not usually found on earth which include tungsten, thorium, gadolinium, europium and zirconium.

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Terrestrial planets have similar structures – a core composed of heavy metals which is usually iron, solid surfaces of craters, canyons, mountains and volcanoes and secondary atmospheres (generated through volcanic activity and comet impacts), as opposed to the gas giants which has primary atmospheres (captured directly from the original nebula). Note that while the moon has similar structure, it doesn't have an iron core. Plutoids are also similar to terrestrial planets in that they have solid surfaces; but instead or rocky surfaces, they are composed of icy materials.

Mercury is one dense planet composed of iron and nickel, with a very thin atmosphere. Venus has a thick atmosphere, mostly of carbon dioxide, which causes a greenhouse effect. Earth has the highest density among these planets with an atmosphere composed of elements that are conducive for human habitation and Mars has a rocky red surface and a thin atmosphere. Note that among these 4, only Earth and Mars has moons; Earth has one and Mars has two). Extra-solar terrestrial planets are the subject of much interest, as people naturally want to know of the existence of other planets that are habitable for humans, or for the theoretical extraterrestrial beings.

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