The star we call the Sun has a number of small objects circling around it. Many other stars in our Galaxy have objects orbiting them too and astronomers have recently discovered a few of these other systems already. The largest members of the Sun's family are called planets, and one of these we call home. That planet, Earth, has many unique characteristics that enable life to exist on it. What are the other planets like? We have learned more about our solar system in the past few decades than probably any other field of astronomy. The planets are no longer just objects up in our sky, but places we have been and explored---worlds in their own right. To give an adequate coverage of each of the planets would fill up a whole book (or more)! Since this web site is an introduction to all of astronomy, I will not explore each planet individually. Instead, I will focus on the common characteristics of the planets such as their Distance relative to us, mass, size and etc.
Distances
Several hundred years ago Copernicus was able to determine approximate distances between the planets through trigonometry. The distances were all found relative to the distance between the Earth and the Sun, the astronomical unit. Kepler refined these measurements to take into account the elliptical orbits. However, they did not know how large an astronomical unit was.
To establish an absolute distance scale, the actual distance to one of the planets had to be measured. Distances to Venus and Mars were measured from the parallax effect by observers at different parts of the Earth when the planets were closest to the Earth.
Knowing how far apart the observers were from each other and coordinating the observation times, astronomers could determine the ...
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Angular velocity = 36 degrees / 4 hours = 9 degree/hour
Full time rotation = 360 degrees / 9 degree/hour = 40 hours
With the invention of radar, the distance to Venus could be determined very precisely. By timing how long it takes the radar beam travelling at the speed of light to travel the distance to an object and back, the distance to the object can be found from distance = (speed of light) × (total time)/2. The total time is halved to get just the distance from the Earth to the object. Using trigonometry, astronomers now know that the astronomical unit =149,597,892 kilometers. This incredible degree of accuracy is possible because the speed of light is known very precisely and very accurate clocks are used. You cannot use radar to determine the distance to the Sun directly because the Sun has no solid surface to reflect the radar efficiently.
In his book, Repcheck recounts how a Catholic Church cleric invented a highly complicated theory of the heavens’ architecture. Copernicus made a breakthrough by solving a significant astronomical problem. Everybody except the astronomers had earlier accepted Aristotle’s concept that heavenly objects revolved around the earth in perfectly circular orbits. The astronomers were opposed to this notion since their calculations could not work according to it. Repcheck introduces Ptolemy who described a cosmos in which the earth positioned itself somewhat off-center and other heavenly bodies revolved in one circular orbit inside a second ideal circle at changeable speeds. Even though Ptolemy’s model was rather complicated, astronomers found it to be reasonable in their calculations. Astronomers were still using this new concept even 1500 years later. In this regard, the author starts to bring Copernicus into the picture.
Our sun is the central pivot point to which or entire planet and solar system is built around. With out it all life on our planet would cease to exist. Within this paper we will explore how our Sun and solar system formed and came to resemble what we see today.
Copernicus was a Polish astronomer born in 1473, in Thorn, Poland and died in 1543. He entered the University of Krakow in 1491 and studied there for four years. In 1496 he joined the University of Bologna in Italy to study church law and studied astronomy on his own time. He was asked to make a new calendar using the geocentric theory, the theory that the sun and moon orbit the earth. He found several flaws with this system and was bothered by it and went on to discover that the planets actually orbit the sun. Galileo supported Copernicus’ theory when he made discoveries with the telescope. We consider Copernicus to be the founder of modern Astronomy.
In 1610, an Italian astronomer, Galileo Galilei, discovered Saturn through a telescope, although it was nothing like we would think of a telescope today (Saturn: Read More). He had thought that Saturn was “triple bodied” because he saw a pair of spherical objects on either side of the planet. Later in the century around 1659 a Dutch Astronomer, named Christiaan Huygens, who had been using a more observant and advanced telescope as compared to Galilei’s, discovered that Saturn was surrounded by a thin, flat ring (Saturn: Read More).
After hearing of this great invention, Galileo was quick to develop himself a telescope; providing the means to make revolutionary discoveries about the universe, that accosted orthodox doctrine of the time. In 1609, Galileo first looked up to the heavens with his telescope. In doing so, he discovered Venus’ phases, and some of Jupiter’s moons, which are now named the Galilean moons. The discovery of Venus’ phases showed that Venus orbited the sun, and the discovery of the moons of Jupiter proved not everything orbited the Earth; these were two crucial components of the Copernican theory. The Copernican theory stated that the solar system was heliocentric, which defied Aristotle’s and the church’s doctrine of the geocentric theory. Later, Galileo discovered sunspots, further abnegating Aristotle’s long held doctrine, which stated the sun was perfect. The Catholic Church
All planets orbit within 3 of the plane of the ecliptic. In addition, all planets also orbit in a prograde orbit which means they all orbit in the same direction. There is a total of four terrestrial planets and 5 Jovian planets. A terrestrial planet is a rocky planet that is composed of rocks or metals. For example, Mercury, Venus earth, and Mars are examples of terrestrial planets because they are small rocky and contain an atmosphere. Earth and Mars, for instance, has a thin atmosphere whereas Venus has a hot thick atmosphere. Jovian planets are the giant planets such as Jupiter, Saturn, Uranus, Neptune and Pluto all have big gasses and many moons. Jupiter, for instance, is a big gas ball mad up of the elements Hydrogen and Helium. All five planets also have rings which mean the planet has a disc orbiting around the
Before the sixteenth century, the common knowledge of astronomy was based off the Ptolemaic model which said the Earth was the center of the universe and everything, including the sun, planets, and the heavenly spheres rotated about its center. It made complete sense at the time because it did account for every planetary motion and it was what the church believed. Claudius Ptolemy came up with this model in about 100 AD for other works of Greek astronomers.
Astronomy’s beginnings can be considered to go back as far as humankind has looked up at the sky in wonder. A simple question then led to an answer that is still being uncovered today. That question: “What is everything up there?” Two-thousand years later, some questions have been answered. Many still remain. However, the process in which these answers have been obtained has not been simple. Many times throughout history, astronomers have believed the answer was in sight and tenaciously believed the idea, only to discover they were wrong years later. These astronomical fads have held the progress of astronomy, and consequently almost all other branches of science, back for hundreds of years as the truth was sorted out. One of the first examples of this was the model of solar system. Aristotle first reasoned that the Earth was at the center and the sun and planets traveled around it on crystalline spheres (Baron 44). The most distant sphere was black and had many small holes punched in it (Baron 44). Behind that was the light from Heaven which shown through the holes making the stars (Baron 44).
Johannes Kepler was a German astronomer and mathematician who lived between 1671-1630. Kepler was a Copernican and initially believed that planets should follow perfectly circular orbits (“Johan Kepler” 1). During this time period, Ptolemy’s geocentric theory of the solar system was accepted. Ptolemy’s theory stated that Earth is at the center of the universe and stationary; closest to Earth is the Moon, and beyond it, expanding towards the outside, are Mercury, Venus, and the Sun in a straight line, followed by Mars, Jupiter, Saturn, and the “fixed stars”. The Ptolemaic system explained the numerous observed motions of the planets as having small spherical orbits called epicycles (“Astronomy” 2). Kepler is best known for introducing three effectual, applicable and valid laws of planetary motion by using the precise data he had developed from Tycho Brahe, a Danish astronomer, which helped Copernicus’s theory of the solar system gain universal reception (“Johan Kepler” 1). Nevertheless, he had made further effective contributions in the field of astronomy, which are valid to society and were used to change how the universe was perceived.
Euclidean distance was proposed by Greek mathematician Euclid of Alexandria. In mathematics, the Euclidean distance or Euclidean metric is the distance between two points, which is shown as a length of a line segment and is given by the Pythagorean theorem. The formula of Euclidean distance is a squ...
The first record of the movement of the planets was produced by Nicolaus Copernicus. He proposed that the earth was the center of everything, which the term is called geocentric. Kepler challenged the theory that the sun was the center of the earth and proposed that the sun was the center of everything; this term is referred to as heliocentric. Kepler’s heliocentric theory was accepted by most people and is accepted in today’s society. One of Kepler’s friends was a famous person named Galileo. Galileo is known for improving the design and the magnification of the telescope. With improvement of the telescope Galileo could describe the craters of the moon and the moons of Jupiter. Galileo also created the number for acceleration of all free falling objects as 9.8 meters per second. Galileo’s and Kepler’s theories were not approved by all people. Their theories contradicted verses in the bible, so the protestant church was extremely skeptical of both Galileo and Kepler’s
To better understand the planets, we need to first have a basic understanding of our
Later after Copernicus came Johannes Kepler and Galileo Galilei, who confirmed some of Copernicus’ observations. Kepler provided concise evidence of planetary motion regarding their path around the s...
As my science fair topic, I chose to test the accuracy of using parallax to measure distance. I chose this topic because it relates to two of my favorite topics: mathematics and astronomy. Parallax uses a mathematical formula and is most commonly used to measure the distance between celestial bodies. From my research on parallax, I found how to measure it, and how to use the parallax formula to measure distances.
Venus, the second planet closest to the Sun and Earth’s closest neighbor, is known for its many wonders and harsh conditions. Venus is possibly the first planet discovered by humans and is said to have been first discovered in 17 B.C. by Babylonian astronomers. Venus is the first planet to be explored by spacecraft although many of these attempts have proven unsuccessful. Fortunately, more than twenty of the spacecraft explorations been proven successful, and through those we have gained knowledge about this wonder of the night sky.