Planets Orbit Around The Sun example essay topic

In the times of ancient Egypt and Greece, the early astronomers didn't have binoculars or telescopes. Yet the astronomers those days gathered the information and pieced together the theories that we now refer too. How did they do this? They would go outside of their huts at night and observe the heavens. They would then repeatedly go out day after day at the same time and chart any differences or similarities they saw.

Over a long period of time this produced outstanding results. One of the major things that these ancient astronomers noticed was that the stars looked a little bit like animals and other items if you connected the dots. So of course they decided to name them, and thus was the origin of the constellations. There are many different constellations, most are named after gods and animals or other general items, and each one has its very own story. That's how the ancient people amused themselves, they didn't have TV's or computers, they only had the stars, Stars that told stories about the "Great Bear", "Orion The Hunter" or "Taurus The Bull". The constellations were also an important tool the ancient people used like a calendar.

They noticed that there were 12 major "constellations" that went throughout the sky and then repeated themselves. They noticed that it took approximately 30 days for an entire constellation to pass throughout the sky. The reason this is, is because of the apparent path that the sun takes among the stars is called the Ecliptic. While the sun is moving along the Ecliptic it passes threw the 12 constellations and this is what created the Zodiac. There were many different views on what the Earth's significance to the universe was and how it worked along with the sun. In 2000 B. C the ancient Egyptians thought that the Sun was a boat that sailed across the sky by the god Ra.

It wasn't until about 400 B. C that this hypothesis was proven wrong. Aristotle thought that the Sun was a fiery ball that moved around the Earth, and then about 100 years later Aristarchus came up with the theory that it wasn't the Sun that moved around us, but us moving around the sun. His idea was rejected at the time. How could we be moving and not feel it? It wasn't until about 400 years later that Ptolemy came up with the theory that the Sun, Stars and planets move around Earth in circles using "Epicycles" We now know that it is a combination of many things, such as that the Earth along with all the other planets orbit around the sun and that each of those planets have separate moons that orbit us all while we rotate ourselves. Only until recently we have been able to find out how to decipher distance in space.

Because the universe is so big, it was difficult before. You can't really take a big measuring stick and touch the sun or a planet or a moon, or you couldn't drive to mars to find out, A because the distances we travel upon the surface of earth are nothing in comparison to the distances in space, and B there is so much space and so little time. Even if we could somehow drive our "floating car" throughout space, it would take many, many lifetimes to get there. Now however we have space shuttles that can exit our atmosphere and go on the very short journey to our moon. One way we calculate distance is to send out a radar beam and calculate how long it takes to return. However again this is nothing in comparison to the area we would need to cover.

The distance to our moon from earth is not even a footstep in comparison to the amount of the universe we still need to see. The way we measure distance in space is in Astronomical Units (AU's) within relation to the sun. For example the distance from the Earth to the Sun is 150,000,000 kilometers (93,000,000 miles) so that is equal to 1 AU. Mars is approximately 1.5 AU's because it is 1 and 1/2 times the distance from the Earth to the sun. So now that also tells us that Mars is 0.5 or 1/2 a AU far from us. Johannes Kepler was a mathematician born in a small town in Germany in 1571 A.D. Because of eyesight problems he decided to focus his attention into mathematical equations and relying on others sightings.

He came up with 3 significant laws that are now a giant contribution to astronomy. Kepler's First Law: Each planet's path around the Sun is and ellipse, with the Sun at one focus of the ellipse. In Somewhat Plain English: An ellipse is a geometrical shape of which every point is the same total distance from two fixed points. So what Kepler means by his first law is that every plant follows a specific Elliptic path around the sun. Kepler's Second Law: A planet moves along its elliptical path with a speed that changes in a way that a line from the planet to the Sun sweeps out equal area in equal intervals of time.

In Somewhat Plain English: Basically what Kepler's second law describes how the orbital speed of a planet changes as a planet revolves around the Sun. A planet moves fastest when its at the nearest point to the Sun (called the perihelion) while it moves most slowly at its farthest point from the Sun (called the aphelion). Kepler's Third Law: The ratio of the cube of the semimajor axis of a planet's orbit to the square of its orbital period around the Sun is the same for each planet. In Somewhat Plain English: Where T is the orbital period in years and a is the semimajor axis in AU.

Kepler's law is also known as the harmonic law, and can also be written in the form Where n is the mean motion of an orbiting body, a its semimajor axis, G the gravitational constant, and M the mass. If a is measured is astronomical units, T is measured in years (so that is measured in y-1, and the central mass is the sun (so that, i. e., the solar mass), then Kepler's law takes the extremely simple form (web) (web) Another influence al person in Astronomy was Isaac Newton. He also developed 3 laws that had a great impact on Astronomy today. Newton's First Law of Motion: Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. In Somewhat Plain English: Newton's first law is pretty self explanatory, what it means is that if a object is in motion it will continue to stay in motion until some type of force is applied. This law is considered to be a extension of Galileo's Law of Inertia.

Newton's Second Law of Motion: The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector. In Somewhat Plain English: This is the most powerful of Newton's three Laws, because it allows quantitative calculations of dynamics: how do velocities change when forces are applied. Notice the fundamental difference between Newton's 2nd Law and the dynamics of Aristotle: according to Newton, a force causes only a change in velocity (an acceleration); it does not maintain the velocity as Aristotle held. This is sometimes summarized by saying that under Newton, F = ma, but under Aristotle F = mv, where vs. is the velocity. Thus, according to Aristotle there is only a velocity if there is a force, but according to Newton an object with a certain velocity maintains that velocity unless a force acts on it to cause an acceleration (that is, a change in the velocity).

As we have noted earlier in conjunction with the discussion of Galileo, Aristotle's view seems to be more in accord with common sense, but that is because of a failure to appreciate the role played by frictional forces. Once account is taken of all forces acting in a given situation it is the dynamics of Galileo and Newton, not of Aristotle, that are found to be in accord with the observations. Newton's Third Law of Motion: For every action there is an equal and opposite reaction. In Somewhat Plain English: This law is exemplified by what happens if we step off a boat onto the bank of a lake: as we move in the direction of the shore, the boat tends to move in the opposite direction (leaving us facedown in the water, if we aren't careful! ). (web) Both Newton and Kepler were geniuses of their time and its possible that if they hadn't come to the conclusions that they did, we might not know what we do today about Astronomy. They were both significant influences and their ideas and theories are commonly still used today, who will be the next? The one who develops a theory for faster then light travel?

Perhaps within our lifetimes it will be possible and we will be populating our neighboring planets, and exploring our brother galaxies. Perhaps in the next 100 years the ideas of Star Trek won't be Science Fiction, they will be Non-Fiction. Only time will tell, after all even if we don't figure it out within the next 100 or 200 or 1000 years, the universe has been around for billions of years, and perhaps not us but our Great grandchildren will find the answers of the heavens. Only time will tell..