The History of Earth

The word planet “Earth” actually has roots in the old English language. For the Greeks, the goddess of the Earth was called “Terra Mater,” or “Earth Mother,” whereas the Roman goddess of the Earth was called “Telus.” Other than Old English, the word “Earth” is also said to originate from German.

Before the fifteenth century, it was believed the Earth was flat, and by sailing towards the horizon, a ship would fall off. However, Columbus is credited with disproving this during his voyage to the “New World.” Afterwards, it was not until the sixteenth century, the Polish astronomer Nicolaus Copernicus came up with a new theory, which involved Earth as being one of the planets, which rotated on its axis and revolved around the Sun. Until this time, it was also believed the sun and planets revolved around Earth.

In the twentieth century, entire maps of Earth were completed, showing the surface of the planet. It was revealed the geographical surface of the Earth is relatively young compared to other planets. This is due to the influence of human beings erasing the earlier surface features from the Earth.

With a diameter of 7,909 miles, the Earth is the densest planet in the solar system, and even though this theory has been debated before, Earth has been discovered to be the only planet with life on it.

The Orbit Of Earth

The orbit of Earth is almost circular in shape, but is not entirely circular like Venus’. The perihelion of Earth is 91.4 miles (147 km), whereas its aphelion is 94.5 miles (152 km). Its closest neighbors are Venus and Mars, and it revolves around the Sun every 365 days.

The Earth is also tilted approximately 23° on its vertical axis, and completes a full rotational period in 23 hours and 56 minutes. This is in contrast to a “day” being 243 days on Venus.

This planet has a considerable magnetic field, which is created by its fast rotation on its axis, and the presence of nickel and iron in its core.

Expeditions From Earth

The first artificial satellite called Sputnik 1 was launched from planet Earth by the Soviet Union in October 1957. Sputnik was able to spend one hundred minutes orbiting around the Earth.

Sputnik 2 was launched in November 1957, making it the second expedition to view the Earth’s surface. The third expedition from Earth, and the first led by the United States Of America, occurred in January 1958. The satellite, Explorer I, was sent off from Cape Canaveral, and was able to discover the zone of radiation located around the planet.

With the launch of Sputnik 1 by the Soviet Union in 1957, the American government allotted more funding for space research, and NASA was created as a result in 1958.

A Day On Earth

If you were “visiting” planet Earth for the first time, the first thing you would notice is the planet’s colors. When viewed from space, the Earth is a mixture of white, blue, brown, and green colors, representing the clouds, water, land, and foliage respectively. Your spacecraft would enter the radiation zone surrounding the planet, known as the Van Allen Radiation Belt, responsible for destroying meteors entering the atmosphere.

The Earth’s atmosphere is different than any other planet. It consists mostly of Nitrogen (78%), Oxygen (21%), and other gases (1%). The concentration of carbon dioxide in the atmosphere varies, and it was believed the Earth contained more carbon dioxide, but over the years, carbon was lost as it was incorporated into rocks. 

It was also believed, the Earth’s atmosphere had no large purpose, other than providing nitrogen for plants and oxygen for humans. However, the atmosphere is able to protect us from the harmful rays of the Sun, and influence patterns in the weather and climate. The upper part of the atmosphere will also expand and contract during the day and night, under the Sun’s influence.

Carbon dioxide located within the atmosphere is also responsible for the greenhouse effect, which helps keep the Earth warmer. If it was not present, instead of 57°F, the temperature would be –4°F. Without the greenhouse effect, the oceans would not be able to remain in the liquid state.

Due to the greenhouse effect, the cloud cover, and the atmosphere, the temperature on Earth only varies by a small range compared to the other planets. The influence of these three factors is particularly obvious when considering how close we are to the Sun, compared to the remaining planets. The ocean currents also have the ability to disperse heat around the Earth, and contribute to the small variation in temperature.

Topographically, the Earth consists of valleys and mountain ranges with areas of volcanic activity with the highest mountain range being Mount Everest. Oceans on the Earth divide the land into continents, with the largest being the Pacific Ocean. There are eight major tectonic plates, along with approximately twenty smaller plates. As the plates move against each other, earthquakes result along fault lines.

One of the most interesting phenomenons seen only on Earth is the Auroras. The Auroras, or the Northern and Southern lights, are produced by the interaction of solar wind and the Earth’s magnetic field. The charged particles of the solar wind are unable to escape the Earth’s magnetic field, resulting in the “light show” known as the Auroras.

The Earth’s Moon

Earth has had numerous artificial satellites sent into space to monitor and report the weather or topography changes of the surfaces. However, the Earth has only one natural satellite or moon.

The Moon is located 238,857 miles from the Earth, and revolves around the Earth approximately every 27 days. The gravity of the moon is 1/6 of Earth’s gravity, and this natural satellite has a diameter of 2,160 miles.

The Moon is similar in appearance to Mercury, and varies in temperature from 212°F to -279°F during the day and night. This temperature range is due to the moon lacking the presence of an atmosphere. Contrary to popular belief, the moon is unable to produce light of its own, and instead “releases” light which has been reflected from the Sun. There are many phases to the Moon, which can be viewed on Earth depending on the portion of its surface that is illuminated.

Basically the Earth’s moon consists of two surface features – smooth low-lying plains called Maria (or “seas”) and craters areas called Anorthosites. The soil composition of Maria is mainly iron and manganese, whereas the soil composition of Anorthosites consists of aluminum with calcium. It is believed the Anorthosites represent older areas in the topography, whereas Maria appear younger in formation. The most famous Mare is the Mare Tranquillitatis, also known as the “Sea of Tranquility.”

Neil Armstrong, along with Edwin Aldrin, accomplished the first American expedition to the Earth’s Moon in 1969, and was the first to walk on the Moon’s surface from the Apollo 11 spacecraft.

Statistics About Earth

References

Encyclopedia Britannica. "Earth." 2006. Encyclopedia Britannica Premium Service. 2006
http://www.britannica.com/eb/article-9110147

National Aeronautics and Space Administration (N.A.S.A). “Earth: Facts & Figures.” 2006
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Earth&
Display=Facts&System=Metric

World Book, Inc. "Moon." World Book Online Reference Center. 2006. World Book, Inc.
http://www.worldbookonline.com/wb/Article?id=ar582880

Earth Images