Atmosphere
The Earth is bounded by a blanket of air, which is known as the atmosphere. The atmosphere is primarily composed of gases such as nitrogen, oxygen, and argon. The remaining gases that make up our atmosphere are carbon dioxide, water vapor, ozone, methane, and nitrous oxide.
The Earth’s atmosphere is divided into four distinct layers: troposphere, stratosphere, mesosphere, and ionosphere. The very bottom layer that is the closest to the earth’s surface is known as the troposphere. The troposphere is the layer known to be the most dense. As you reach higher into the layer, the temperature drops from about 17 degrees Celsius to -52 degrees Celsius. The troposphere is where all the Earth’s weather takes place, which contains all the rising and falling air. Also, there is a thin layer called tropopause that divides the surface between the troposphere and stratosphere. The stratosphere is the layer that has a horizontal air flow. When compared to the troposphere, the stratosphere is less dense and dry. Due to the absorption of the ultraviolet radiation, the temperature in the stratosphere gradually increases to -3 degrees Celsius. It contains the ozone layer that we are very familiar with. The ozone layer is the concentration of ozone, the reactive form of oxygen, which absorbs the ultraviolet radiation from the Sun. Today, there are many studies involving the ozone layer. People today are using many substances that have ozone layer depleting gas. This can cause the thinning of or even creation of holes in the ozone layer. The ozone layer depletion causes people to get exposed to high level of ultraviolet radiation, which can cause skin cancer. Located right above the ozone layer is the mesosphere. As you increase in altitude in the mesosphere, the temperature can decrease to as low as -93 degrees Celsius. The mesosphere has strong atmospheric tides, which is an analogue to ocean tides. The last layer, also known as the outer most layer is the thermosphere. As you increase in altitude in the thermosphere, the temperatures can increase as high as 1,500 degrees Celsius. In the thermosphere, the air is really thin thus, small changes in energy can cause dramatic changes in the temperature. In the thermosphere, there is a region known as the ionosphere, where many atoms are ionized and absorb the most energetic photons from the Sun.
Axis
The earth's axis is very unique. Let’s first find out what an axis is. Normally, axis is either an imaginary or a physical line that prescribes an object’s movement. An example for a physical axis is a tight string that goes through the center of a spinning ball. An example for an imaginary axis can be the Earth’s axis. The Earth’s Axis is an imaginary line that has the center point for gravity. It goes through the north and the south poles and spins around them. It is part of the Earth that is not really moving like the Earth itself. Unlike most of the physical objects that have an axis, Earth does not spin straight up and down but it is actually tilted. It is tilted perpendicularly about 23.5 degrees, which is inclined 66.5 degrees from the Earth’s orbital plane.
We know that the amount of sunlight that Earth receives changes during the period of year, which gives us four seasons. This is because as the Earth rotates round the sun, the tilt of the axis does not change. Therefore, the Earth receives different amounts of sunlight as it revolves the sun. This is why the daytime for summer is longer than the winter. During summer, the axis points towards the sun but during winter, the axis points away from the sun and gives less sunlight than summer.
Composition
The 7th planet in our Solar System, Uranus, was also the first to be discovered after the invention of the telescope. Even though the planet is quite dim, it is visible to the naked eye during clear skies. Sir William Herschel accidently discovered Uranus on March 13, 1781. Before Herschel, nobody had any official records of the planet. Therefore, he is the original discoverer. He used his strong home-made telescope to observe a region in the sky that was in the constellation of Taurus, but later he noticed it was quite large for a star. At first, he recorded a discovery of a faint object that he speculated to be a nebulous star or perhaps a comet. Herschel was almost so certain that the object was a comet that he presented it as a comet to the Royal Society. By doing this, he found out from the Astronomer Royal, Nevil Maskelyne, that the object lacked a tail and orbited around the Sun like the rest of the planets. This discovery impressed King George III of England so tremendously that he rewarded Herschel a yearly stipend of 200 pounds. As a form of respect to the king, Herschel originally wanted to name the new found planet, Georges Star. However, the international astronomy community pushed more for Uranus, a Greek name, while the rest of the planets were named after Roman gods. Other than the Astronomer Royal, other astronomers contributed in the conclusion of Uranus being a planet rather than a star. Anders Johan Lexell, a Russian astronomer, was first to calculate the orbit of the object. The new objects almost circular orbit is what allowed him to conclude that it was a planet after all.
Moreover, about a century earlier, there was another person who had documented the observation of Uranus. This man was John Flamsteed. From 1750-1769, Pierre Lemonnier, a French astronomer, observed the planet many times as well. They both thought that the object was a star. Therefore, they are not accounted for as the original discoverers of the planet because they were not the ones to recognize it as a planet. Furthermore, better details about Uranus were more observable over time as higher quality telescopes were invented. In 1986, the first and only spacecraft from Earth so far was able to land on Uranus. This spacecraft was NASAs Voyager 2 that flew within 8,500 km of Uranuss cloud tops. During this voyage, NASA discovered 10 new moons and 2 new rings around the planet.
Crust
The crust of the earth is extremely thick.
The Earth’s crust is the outer most surface of the Earth which covers the earth’s mantle. The crust is much thinner than the other layers. The Earth’s crust floats above the denser, softer mantle. It is about 25 miles thick beneath the continents and about 6.5 miles thick beneath the oceans. It is about less than one percent of the entire depth of the Earth. The Earth’s crust is distinguished into two portions: oceanic crust and the continental crust. The continental crust is much different from the oceanic crust. One of the biggest different between the two is their difference in density. The oceanic crust (3.0 g/cm3) has a higher average density than the continental crust (2.6 g/cm3). This density difference is what allows the continents to float on the upper mantle for billions of years. The oceanic crust on the other hand, can barely float on the mantle. As the oceanic crust gets older, it builds up a heavy under layer of cooled mantle rock which results in a two-layer structure causing it to eventually sink into the mantle from its own weight. As it sinks, it is melted down and recycled. Due to this recycling process, the age of the oceanic crust is never older than 200 million years. Another difference is in their composition. The oceanic crust is composed of denser rocks such as basalt. Basalt rocks are formed out of liquid lava which tends to cool off rapidly. On the other hand, the continental crust is composed mostly of lighter rocks such as granite, which are less dense than basalt.
The region just below the crust is known as mantle. When compared to the crust, the mantle is relatively flexible thus allowing it to flow rather than fracturing. The mantle is about 1800 miles thick and about 5400 degrees Fahrenheit. Although the temperature is very high, because of its high pressures, the rocks remain solid. The inner most part of the Earth, which is beneath the mantle is the core. It is consisted of two different parts: inner and outer. The inner core is solid and the outer core is liquid because of the temperature and pressures. The Earth’s source of magnetic field comes from the outer core, which contains iron.
Who Invented Earth Flags?
There are few symbols that have more meaning than a flag. In the case of nation, a flag is a source of great pride, history and loyalty. Likewise, it is not uncommon to find causes, organizations and movements that also rely on the power of flags to unite people under a specific goal or message. The fact that flags mainly relate to a specific group of people makes it difficult to picture a flag that is intended to encompass an entire planet, but in actuality there are multiple examples of this. There have been several designers that have set out with task of creating a flag of Earth.
The most famous Earth Flag was created by John McConnel in 1969. John McConnel was a well known environmentalist and peace activist whose dedication to the betterment of the world can be connected with the establishment of Earth Day. The flag is simple enough in design, the background of the flag is dark blue and the center is covered with a NASA photograph of Earth from space. As a result of the history of the flag and its creator, this Earth flag has been associated with environmental awareness and the Earth Day movement. Another Earth flag was created in 1970 by James W. Cadle’s. His flag, which he deemed the “Flag of Earth,” has a large blue circle in the center, which represents the Earth. On the right side of the circle is a black background with a small white circle representing the moon and on the left side is a yellow background, which represents the sun. A more recent Earth flag was designed in 1993 by Luis Alonso Salvador. The flag has three horizontal background colors: yellow on the bottom, representing land; dark blue in the middle representing the oceans; and light blue on the top representing air. At the center of the flag lies a blue circle, a yellow star to the right and white semi-circle to the left, representing the earth, stars and moon respectively. Other less well known Earth flags have been created, such as the Universal Peace Congress’s Earth flag which consist of the Earth over a field of blue with white stars. Additionally, many people consider the United Nations flag as an Earth flag as well.
Whether it is the flag designed by John McConnel, James W. Cadle or Luis Alonso Salvador, Earth flags exist and have a great deal of meaning. As one can see, there are a variety of physical differences between the different Earth flags; some used NASA photographs and others used more symbolic shapes and colors. Regardless of these differences however, Earth flags have come to stand for an overarching positive message. By creating a flag that attempts to overlook the boundaries of nations, race and religion, Earth flags represent a commitment to unity. By placing the Earth on a flag it is also a way paying homage to the environment and acknowledging the fact that it takes human effort to help maintain and improve it.
Earth Day
Earth Day is a well known day dedicated to the environment. In general, Earth day is a period of time that is intended to increase awareness and appreciation of the natural environment and ways in which people can help the environment on a daily basis, but the effort it took to establish this day are often taken for granted. The late 1960s and early 1970s marked the world’s first real interest in environmental conservation. Previously, the Earth’s environment was a side note, as well as being an issue easily overlooked by governments across the world. As was a key component of the time, people started to bring important issues to light through protests and other forms of activism. Issues such as air pollution, water pollution, toxic dumping, etc., which were once of little consequence, quickly became headlining issues. The environmentally aware era of the 1960s can be considered an important catalyst to the formation of Earth Day.
Today Earth Day has turned into an international event, but in 1970 there was not a uniform Earth Day, instead there was one leader’s dream and separate events that took place across the country. The principle leader and credited founder of Earth Day is Senator Gaylord Nelson. Nelson was a member of the Senate that new the importance of the environment and wanted to spearhead a program that would educate Americans and help gain support for an environmental agenda in coming years. Nelson felt that the most effective model for improving awareness would be through environmental teach-ins. These teach-ins, which were also used for the Vietnam War, would take place on every university campus in the nation. To allow for the most potential participation, Nelson chose a time where college students did not have to worry about exams or major holidays, April 22, as the day for his Earth awareness teach-ins. Nelson’s objective gained a great deal of support and in its inaugural year, Earth Day had more than 500 million participants. The key to Earth Day’s initial success was the fact that there was not a specific governing body managing the event. Instead, the implementation of Earth Day was left to individual activists groups, which were most commonly led by students. The result was self-started, autonomous Earth Day events that took place across the country. For example, the 1970, New York Earth Day was organized by student activists and led to the shutting down of 5th Avenue and Central Park. Over one million people participated in the event and it was supported by then New York Mayor, John Lindsay. Philadelphia also hosted its very own Earth week from April 16-22. Also led by students, this event spent a week educating about and celebrating the wonders of the Earth.
In the decades that followed the first Earth Day, efforts grew to consolidate efforts and gain support. In order to concentrate the efforts of the thousands of individual community organizations that supported Earth Day, organizations such as Earth Day USA and the Earth Day Network were formed. These groups bring together NGOs, local governments, activists groups and other environmental aware parties, in order to encourage environmental education on a local, national and international level. The Earth Day Network currently boasts of having over 10,000 groups and 100,000 educators. With the combined efforts of international groups, more than 170 countries and 1.5 billion people have been included in Earth Day, making it one of the world’s most widely celebrated annual events.
3 Mysteries abour Earth
For hundreds of years, scientists have been looking towards space to try and find answers about other planets. Whether it is through attempts to analyze the composition of other planets or trying to pinpoint how they were created, some answers have been found. Another recent trend is an attempt to find a planet very similar to Earth somewhere in the out reaches of space. Ironically, while scientists have been searching for answers about Earth-like planet, there are still questions that remained unanswered about the Earth. More specifically, there have been three events that scientists still struggle to explain today: the Tunguska event, the supposed Clovis Comet and the cause of a dramatic poll shifts in Earths distant past.
The Tunguska Event was a very large, unexplained explosion that occurred on June 30, 1908 in Siberia, Russia. The explosion took place three to six miles above the Earth’s surface and had a recorded blast range of 10-15 megatons of TNT, which translates to a blast 1,000 times more powerful than the atom bomb dropped on Hiroshima, Japan. Eyewitnesses described a blue light, followed by a bright flash and loud sound similar to artillery fire. The great fireball that ensued was so powerful that the shock wave was felt extensively though Eurasia. This event remains to be one of the most powerful and least understood explosions in our planet’s recorded history. A host of theories have been developed to try and explain for the Tunguska Event. Some of the explanations are admittedly farfetched– some tried to attribute the event to an alien spacecraft crash or a black hole entering the atmosphere–but others are based on proven science. The most accepted theory of the Tunguska Event attributes the devastating explosion to a meteoroid. While meteoroids enter the Earth’s atmosphere daily, it has now been discovered that a great deal of them actually explode before reaching the Earth’s surface. This occurrence, which is known as a meteoroid airburst, usually takes places in the upper atmosphere, but in rare cases, such as the Tunguska Event, can occur closer to the ground. Scientists are not certain that their meteoroid airburst theory is correct, because competing comet and natural H-bomb theories have scientific footing as well. All that is known for sure is that the Tunguska Event can be categorized as one of Earth’s greatest mysteries.
Another one of Earth’s most debated mysteries is the Clovis comet that supposedly hit North America around 13,000 years ago. Scientists argue that the Clovis comet was responsible for the mass extinction of many North American species such as the mammoth, dire wolf and saber tooth tiger, along with the elimination of the Clovis civilization, which was one of North America’s first new world civilizations. It is argued that the Clovis comet hit somewhere near the Great Lakes region and caused vegetation destroying fires and sun blocking dust clouds. Support for this theory was made with the discovery of unusual levels of spherical magnetic particles, nanodiamonds and iridium content, which all indicate the presence of meteorites and the presence of charcoal that would support the wildfire theory. A 2010 study has made great strides to disprove this theory however. Scientists have explained for the presence of these particles through various means. It is believed that magnetic spherules were concentrated because of rainwater and it has been discovered that nanodiamonds are constantly finding their way to the Earth’s surface. Likewise, the presence of charcoal was only found around Clovis civilization dwellings, meaning that they were from controlled cooking fires and not the result of a cataclysmic event. With little proven evidence for the Clovis comet, scientists are left to wonder what exactly wiped out so many species in such a relatively short amount of time. Theories about disease carrying animals from the Bering Strait and human hunting to extinction also exist, but they also fail to explain for the mass extinctions 13,000 years ago. Science has disproved the Clovis Comet, but by doing so, has also greatly added to the value of this mystery.
The last of the three mysteries of Earth has to do with a dramatic climate shift that occurred tens of thousands of years ago. For scientists, an unlikely character, the woolly mammoth, plays a great role in the polar shift debate. There have been multiple documented cases of mammoth’s being found completely preserved in ice, with plants still undigested in their mouths and stomachs. In cases where an animal is preserved like this, scientists are shown that the animal experience a quick and sudden death, unprepared for the sub-zero weather that engulfed it. What makes things even stranger is that the plants found in the stomachs of mammoths are from tropical climates, a long distance away from the animal’s icy tomb. The only way to explain for this would be a dramatic polar shift that resulted in instant changes in weather. Science is currently struggling to try to explain how this could happen. Some scientists blame an outside cosmic event, but more recently a better explanation has been found. Many scientists argue that such a drastic shift in the planet’s temperature can only attributed to realigning of the planet’s poles caused by a shift in the planet’s electromagnetic field’s polarity. This remains a theory however, until more understanding can be gathered about the cause of electromagnetic field shifts.
These three events are only a peak into the many Earth mysteries that challenge scientists on a daily basis. This does not mean the cause is hopeless however; because as new theories arise and old ones get disproved, science continues to get closer to the truth. Hopefully, someday soon these three mysteries will be definitively solved.
Electromagnetic Field
The earth consists of not one but two fields.
The earth is often times considered a baby, although it is roughly 4.6 billion years old, the earth in comparison to other planets in other galaxies or even some within our own, is significantly younger. However, an interesting characteristic of the earth is its electromagnetic field known as a magnetic dipole, meaning that it consists of two fields that range in different poles the north and south. These magnetic poles are ironically posted geographically on their magnetic opposites. Meaning that the north magnetic pole resides on the geographic south pole, and the south magnetic pole residing on the geographic north pole. The origin of this concept regarding Earth’s electromagnetic field can best be understood through the dynamo theory. The dynamo theory basically stating that the process of rotating, convecting, and electrically conducting fluid will basically create a electromagnetic field big enough to fit the earth.
The purpose of the electromagnetic field is to protect the somewhat sensitive earth to the shear solar winds that are stream from the sun. Streams of these energetic charged particles usually have energy between 10 and 100 keV, and could technically rip the earth to shreds. However, these particles are deterred or blocked by this magnetic field in order to ensure the earth is not harmed. The act of blocking these particles is known as Lorentz force, which is the force due to electromagnetic fields through induction and the formula F= q[E+ ( v x B). This basically stating that A positively charged particle will be accelerated in the same linear orientation as the field, but will curve perpendicularly to both the instantaneous velocities.
The sun emitting these particles has the capabilities and can destroy the earth and its various layers, but due to the electromagnetic field, instead the particles bounce off of the shield very much like water on an umbrella. The earth’s electromagnetic field originates from the core of the earth, yet is so powerful that it actually deters the particles outside of the earth, and even before they are able to reach the outmost layer of the atmosphere. Without the earth’s electromagnetic field, the earth and every single entity that originates from the earth would most definitely be desolated. However, due to the earth’s magnetic field the exponentially powerful particles of the sun create a safe environment for the earth and its inhabitants.
Earth's Formation Theories
The enigmatic origins of Earth have captivated human curiosity and engaged scientific investigation for countless generations. In the pursuit of comprehending our planet's genesis, an array of Earth's formation theories has emerged, each offering distinct perspectives on the intricate processes that have shaped our world. From celestial collisions and the interplay of cosmic dust clouds to the intricate ballet of gravitational forces, these theories serve to illuminate the dynamic mechanisms that have meticulously sculpted Earth into the vibrant and diverse sphere we call home. In the following discourse, we embark on an intellectual journey across temporal and spatial dimensions, delving into the captivating hypotheses that have been formulated to elucidate the remarkable narrative of Earth's inception.
The Accretion Theory: Constituting the Planetary Fabric
At the foundation of our exploration lies the Accretion Theory, widely acknowledged as the preeminent explanation for Earth's formation. This theory posits that approximately 4.6 billion years ago, a swirling assemblage of gas and cosmic dust known as the solar nebula commenced a gravitational collapse. Through this process, the nebular material began to rotate with increasing velocity, leading to the formation of a disk-like configuration.
Within this whirling circumstellar disk, minuscule particles of dust and rock coalesced due to mutual gravitational attraction, giving rise to progressively larger bodies. Over time, these embryonic entities matured into planetesimals, fundamental constituents in the formation of planets. Guided by innumerable collisions and the ceaseless accretion of matter, these planetesimals gradually amalgamated, culminating in the formation of Earth, an intricately structured world.
The Giant Impact Hypothesis: Celestial Collisions and Lunar Genesis
Transitioning from the subtle orchestration of accretion, we encounter the Giant Impact Hypothesis, an intricate narrative of celestial interaction that unfolded billions of years in the past. This proposition posits a dramatic scenario in which a protoplanetary body, comparable in size to Mars and named Theia after the ancient Greek Titaness, collided with a nascent Earth in a cataclysmic event.
The colossal energy released during this cosmic encounter resulted in the ejection of substantial debris, coalescing into an orbiting mass. Over an extended period, this conglomerate of fragments gravitationally aggregated, ultimately bestowing Earth with its luminous companion—the Moon. Thus, the resplendent lunar entity that graces our night sky is the enduring legacy of an extraordinary cosmic altercation.
Panspermia: Interstellar Conveyance of Life's Building Blocks
Venturing into the realm of speculative intrigue, we encounter Panspermia, a concept that transcends terrestrial boundaries by suggesting the potential extraterrestrial origin of life on Earth. This notion proposes that the fundamental constituents for life, including organic molecules and microorganisms, traversed the cosmos aboard comets, asteroids, or other cosmic vessels.
These resilient envoys of life navigated through the cosmic expanse, ultimately establishing residence on our hospitable planet. In this scenario, Earth becomes a sanctuary for interstellar wayfarers, hosting a myriad of microbial pioneers that embarked on an odyssey through the universe to ensure the propagation of life.
The Ongoing Discourse and the Pursuit of Knowledge
In the culmination of our exploration, it is imperative to acknowledge that the scientific community continues to engage in active discourse and inquiry surrounding these theories. While the Accretion Theory commands substantial consensus within the scientific milieu, the allure of alternative explanations, as demonstrated by the Giant Impact Hypothesis and Panspermia, perpetuates an atmosphere of vibrant exploration.
In fostering an environment of perpetual inquiry, science unveils new layers of the universe's enigma. As humanity remains steadfast in its pursuit of unraveling the mysteries encapsulating Earth's origin, the unfolding narrative invites us to speculate and question, driving the boundaries of human knowledge ever forward.
Embracing the Cosmic Enigma
Thus, our intellectual odyssey has traversed the cosmos, weaving through captivating theories that endeavor to elucidate Earth's formation. From the subtle elegance of dust particles coalescing to the cataclysmic ballet of celestial bodies, these theories weave a tapestry of Earth's origins that beckons us to partake in the perennial wonderment of the universe.
As we continue our gaze skyward, the cosmic conundrum of Earth's birth remains a captivating enigma. In acknowledging the limitations of current understanding and embracing the enigmatic, we are reminded that it is the relentless pursuit of knowledge that propels us forward on this ceaseless voyage of exploration.
Fresh Water
The fresh water on earth is of enormous importance.
The water cycle, which is the movement of water through the hydrosphere, begins with evaporation. The sunlight makes the water on Earth’s surface to evaporate, which then enters to the air as a gas. Also, it can be done from the loss of water from leaves. Once the water enters the atmosphere as gas, it goes back to liquid state and forms clouds. When the water droplets in the clouds get large, it becomes precipitation and goes down to the surface of the Earth again. That precipitation goes to body of water and it repeats its cycle again.
96.5%, which is the majority of water in Earth comes from the oceans. Remaining 1% comes from the saline ground and lake water. Other 2.5% is the fresh water. From that 2.5%, 68.6% of fresh water is glaciers and ice caps, 30.1% is groundwater and remaining 1.3% is surface and other fresh water. Those surface and other freshwater comes from, 73.1% ice and snow and 20.1% from lakes. Remaining portion is shared by atmospheric, biological, river, swamp and soil waters. Earth’s fresh water is water that contains less than 0.2% of dissolved salt. It is usually found in rivers, lakes and groundwater and the fresh water is only found in 2.5% of Earth’s entire water. Moreover, about 2% is frozen away in glaciers. Therefore only about 0.5% of those fresh water is available to both human and animals because most of the fresh water in Earth is atmospheric vapor, salt water, and icecaps. However, even the remaining portion of water is getting polluted as the population increases.
History
Its been over 4 billion years, but we don't know as much as you may think.
The earth has been around roughly 4.6 billion years ago, and has had various stages that have helped form its current and final stage in the current year 2011. About 4.54 billion years ago, the first eon was present, Hadaen, during this period of time, the earth was consistently being bombarded by meteorites which lead to heavy volcanism due to the geothermal gradient. However, about 3.8 billion years ago, the Archeon eon become apparent, which lacked various resources and elements that would be necessary for primordial life to live, such as oxygen and an ozone layer. Jumping billions of years forward, the earth started to slowly develop necessary entities for life to be sustainable. The ocean and atmosphere of the earth started to form when steam escaping from the crust of the earth interacted with gasses from the volcanoes to form the atmosphere. As for the ocean, scientists are still unsure as to how the ocean was formed, but the best guesses are because of apparent comets that contained ice.
The continents that are formed today are relatively new when considering the age of the earth, prior to what is today seven individual continents, the earth had one giant continent that was formed through the shifting core , crust, and mantles that were present. However, due to deterioration, it is thought that what continents we are living on today, are just cratons, or left overs of the previous two eons. These cratons however, are what the first form of life have been thought to walk on. The first form of life has no actual foundational evidence, but rather theories that derive from either aliens or the idea of evolution.
There are many uncertainties about how the earth had formed, due to it dating back to about 4.6 billion years ago. Only scientists and other scholars can imagine as to how it started to form, but truthfully the earth’s formation is still a mystery within itself.
Timeline
Earth’s history started 4600 million years ago with the formation of planet Earth from the accretion disc revolving around the young Sun. About 500 million years after Earth cools and the surface solidified. Then about 3.8 billion years ago, prokaryotes or group of organisms that comprehend bacteria and archaea. This period of time is known as Hadean Eon, which is the period of start of the Earth. Then, Archean Eon comes, which is the beginning of the Earth. About 3500 million years ago, the split between bacteria and archaea occurred and about 500 million years later, Cyanobacteria, or a phylum of bacteria that obtain their energy through photosynthesis, evolved. Proterozoic Eon, or the early life occurred after. In this period, Eukaryote, or the cells contain complex structures enclosed within membranes evolve about 1850 million years ago. Then, sexual reproduction occurred about 500 million years after and the earliest fungi evolve about 700 million years later.
Then, we step into Phanerozoic Eon, or the period of well-displayed life. There are 3 Eons under Phanerozoic Eon, including Paleozoic Era, Mesozoic Era, and Cenozoic Era. During Phanerozoic Eon, about 530 million years ago, living organisms started to evolve in the oceans and the first known footprints on land were dated. First signs of teeth in fish were discovered about 410 million years ago and for 200 million more years, sharks, crabs, beetles and many other creatures evolve. During Mesozoic Era, earliest dinosaurs were found 225 million years ago and first mammals, ants, and other cells and creatures evolve. Lastly, Cenozoic Era, which is the time period between 65.5 million years ago to present, animals and plants that we know today evolve and about 2 million years ago, the first evidence of homo evolve.
Magnetic Field
The Earth’s core is hotter than the Curie temperature of iron, which is about 770 degrees Celsius. This makes impossible for the Earth to have magnetic field. However, despite the fact, Earth does have a magnetic field. When you think of Earth’s magnetic field, you can think about a bar magnet. Just like a bar magnet, Earth’s magnetic field is a magnetic dipole with the magnetic field on the South and the North poles. The magnetic field South Pole is near the Earth’s geographic North Pole and the magnetic field North Pole is near the Earth’s geographic South Pole. Because of the Earth’s axis, it is tilted 11 degrees from the spin axis of the Earth.
Magnetic fields are always surrounded by electric currents. Therefore, scientists are guessing that Earth’s molten metallic core with the circulating electric currents made it possible for the Earth to have a magnetic field. The biggest help that magnetic field gives the Earth is that it protects the planet from space radiation, which is caused by the Sun’s solar wind. They are highly charged particles that burst out from the Sun like a wind. Without the magnetic field, that strong solar wind will strip away out atmosphere. Scientists are predicting this is what has happened to Mars. Therefore, the Earth’s magnetic field helps protects us from getting irradiated. The location of the North and the South magnetic field is not always the same. The Earth’s magnetic field reverses itself every 250,000 years.
Population
Each passing century - the earth becomes more advanced and populated.
Earth’s population is the number of humans living on Earth. According to the United States Census Bureau, the population has reached 6.91 billion and the scientists are expecting it to reach 8,1 billion in end of 2024. The population has been growing steadily since 1350. The population is still increasing and is expected to grow up to 10.5 billion by 2050. Asia accounts for about 60% of the world population, having about 4 billion people. Africa accounts for 15% of the world population, having about 1 billion people. Europe accounts for 11%, Latin America accounts for 9%, North America accounts for 5% and Australasia accounts for less than 1% of the world’s population.
In 70,000BC, the population has declined in huge numbers because of Toba supereruption, which is known as the Earth’s biggest eruption in the history. After that incident, population has been stabilized until the development of agriculture. With the development of agriculture and industrial revolution, the life expectancy for children has increased a lot. Between 1960s and 1970s was the peak of the population growth. The three largest population countries include People’s Republic of China, India and United States. People’s Republic of China’s population is about 1,343,110,000, making 19.4% of world’s population. India’s population is about 1,195,820,000, making 17.3% of the world’s population, and the United State’s population is about 311,058,000, making 4.5% of the world’s population.
Seeing Earth from the Moon
Have you ever wondered what Earth would look like if you were to stand on the moon? Astronauts have wondered this same question. They explored this question by taking pictures of Earth from the moon. Earth is quite large in comparison to the Moon. As a result, it is possible to view Earth from the moon’s perspective. Earth looks like a small, blue sphere from the moon; therefore, to see Earth at all, one must be on the near side of the moon. NASA’s images have shown fascinating things about Earth. Did you know that Earth has lunar phases that you can witness from the moon? These phases are similar to the ones that we see of the moon from Earth. One side of the moon always faces Earth because they are tidally locked with one another. As a result, it takes the same length for the moon to rotate around its own axis as it does to revolve around Earth. It is possible to see over half of the moon’s surface over time from Earth or more than half of the Earth’s surface from the outer edge of the moon because of the moon’s libration. In July 1969, during the Apollo 11 mission and when Neil Armstrong walked on the moon, a picture of Earth going through a crescent phase was taken and served as proof of this phenomenon. Moreover, from any part of the moon’s near side the Earth’s waxing and waning phases can be seen the same way we can see the moon’s phases from Earth. All of the Earth’s quarters and waxing and waning gibbous could be seen from the moon. Also, The sun is always illuminating half of the Earth or moon; therefore, the various phases of the Earth or moon can be seen from either world. In addition, in consideration of the moon’s slow rotation, from most locations of the moon, Earth doesn’t seem to rise or set due to the fact that one side of the moon always faces us. As an alternative, from any point of the moon’s near side, it will always be visible that Earth is hanging in your sky.
Rotation
How fast does the earth actually rotate?
The Earth rotates around its axis, which is an imaginary line that has the center point for gravity. It goes through the north and the south poles and spins around them. Earth does not spin straight up and down but it is actually tilted. It is tilted perpendicularly about 23.5 degrees, which is inclined 66.5 degrees from the Earth’s orbital plane. Therefore, the Earth rotates toward the east side in counter clockwise direction. Earth takes 23 hr 56 min 4.1 sec in Sidereal Period, which is the rotation time for the Earth and 24 hr 0 min 0 sec for Synodic Period, which is the time that the sun takes to make one rotation on the sky. Our clock time is based on the Earth’s rotation to the sun.
There are three different types of days related to the Earth’s rotation. True solar day is the Earth’s rotation period relative to the sun. It is longer than the regular solar day and is dependent on the Earth’s orbital motion. Mean solar day is the average of the true solar day over an entire year, which contains about 86,400 mean solar seconds. Last one is the stellar day, which is relative to the fixed stars. It is 86,164.098 903 691 mean solar seconds and is shorter than the mean solar day. The velocity of Earth’s rotation effects lot of features in the Earth. It effects Earth’s climate, ocean current, Earth’s shape and many more.
Second Moon
any people are shocked to learn that there is another moon that is discussed.
Growing up, we all have learned and saw that there is only one Moon in the sky. However, there is an object that is considered as the Earth’s second Moon. It orbits around the sun in approximately 1:1 orbital resonance with the sun. Although it seems like the second Moon, it is not really the second “Moon” because the Earth’s gravity does not affect it and it’s not affected by Earth like the real moon. It is actually a quasi-satellite, known as 3753 Cruithne. It was first discovered by Duncan Waldron on the October 10th 1986, in Australia. Duncan was the person who actually was responsible for locating this quasi-satellite. Its diameter is about 3 miles, the mass is about 130,000,000,000,000kg, and the temperature is about 2 degrees Celsius.
From 1994 to 2015, Cruithne made and will continue making a closest approach to the Earth every November, which is 30 times the distance between the Earth and the Moon. It takes about 770 years for Cruithne to orbit the Earth and takes about 364 days to revolve around the sun. We know that it takes 365 days for the Earth to revolve around the sun. Therefore, eventually, Earth is going to end up following Cruithne because Cruithne becomes quicker than the Earth for revolutions. Therefore, the orbit and the Earth will pull away from each other. The last time Cruithne was seen is 1902 and the next time will be 2292.
Who Discovered Earth
The question, “Who discovered Earth, seems to be a fairly ridiculous one. How can anyone discover the Earth? The first set of eyes to look down, in a technical sense discovered the Earth, right? Though it is an awkward question, it still one that needs to be posed, because although humans have lived on this planet for thousands of years, our understanding of the Earth has not always been what is today. For example, Greek philosopher Philolaus was documented to have one of the earliest understandings of Earth as a planet in space. His works date back to 385 BCE, but more concrete understandings would not be established until many years later. The question of who discovered Earth as we know it becomes more relevant when it is acknowledged that it was not in the too distant past that humans thought the world was flat and that the sun orbited around the Earth. While, many of the previously held ideas about the Earth may seem comical today, they were considered to be scientific fact at one point in time. It is through this shift between misunderstanding and reality that we attempt to answer the question, “Who discovered Earth.”
In terms of discovering Earth in a modern understanding, Nicholas Copernicus can be given a great deal of credit. Countering the accepted beliefs of the time, Copernicus spent many years developing a heliocentric model for our solar system, which places the sun at the center of the solar system. This correct model was the first scientific acknowledgment of the, now undeniable, workings of our solar system. His work, De revolutionibus orbum coelestium, which translates to On the Revolutions of the Celestial Spheres, outlined seven basic assumptions that were groundbreaking for his time period. The most notable of the seven assumptions included: there is no one center of all celestial spheres; the Earth is not the universe, but is the center of our gravity and moon; and that all spheres in our system use the sun as the mid-point of their revolutions. Many people were interested in Copernicus’s theory, but because of scientific, and possibly religious, concerns, he decided not to release the work until his death. Copernicus’s theory was renounced three years after his work’s 1543 release; the Catholic Church condemned his work, because it countered scripture. Although, Copernicus’s heliocentric theory was condemned, it was not forgotten. In the very near future, noteworthy astronomer Galileo was able to provide additional evidence for Copernicus’s model by observing Jupiter and its orbiting moons, along with the discovery of Venus’s moon-like phases.
While the question of who discovered the Earth may still seem ridiculous to some, it is actually an important question. For hundreds of years, the Earth was considered to be the center of the universe, but this dated and incorrect world view had to be torn down. Like so many other times in history, a scientist comes forth that completely redefines the world as we know it. In 1543, Nicolas Copernicus did just that by publishing his work outlining a heliocentric solar system model. Although it took some time before society could accept the model, it would prove to be a major part of scientific history and marked the beginning of mankind’s correct understanding of the Earth. lved.
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