Earth Solar System

4 Key excerpts on "Earth Solar System"

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  Physical Geography

  Great Systems and Global Environments

  • William M. Marsh, Martin M. Kaufman(Authors)
  • 2012(Publication Date)
  • Cambridge University Press

    (Publisher)

  41 The Organization and Motion of the Planets 3.4 The Organization and Motion of the Planets Our next question is how the Solar System operates because the motion of the Earth in space influences the geographic distribution of solar radiation on a daily and sea- sonal basis. These variations in turn set into motion a wide range of environmental change for most places including that associated with weather and climate, biological productivity, animal migrations, ocean circulation, land-use activity, and many other phenomena. For as long as we know, humans have had an abiding curiosity about the organi- zation and motion of the Solar System. In the clear skies of ancient Mesopotamia, Egypt, Greece, and Rome, the study of the heavens became a preoccupation for many and led to a host of ideas, some fanciful, some not, on the origin, structure, and motion of the Universe. Among these early thinkers was the astronomer and geographer Ptolemy who laid out a model of the Universe with Earth at its center, and the planets and stars revolving around it. The early Christian church liked this geocentric concept, for, among other things, it supported the belief of a Universe centered on Earth, the biblical home God created for Man. The Ptolemaic model became Church doctrine, and while civilization struggled through 1000 years of the Middle Ages, it remained secure under the vestments of Christian dogma. Heliocentrism: In the 1500s, however, a new idea was introduced by the Polish astron- omer, Nicolaus Copernicus (1473–1543). Copernicus revived the old Greek model that the Sun rather than Earth was the center of the heavens and that the Earth and the other planets revolved around the Sun. He placed the orbits of Mercury and Venus next to the Sun, followed by Earth, and then Mars, Jupiter, and Saturn (Uranus, Neptune, and Pluto were at that time unknown). Around this heliocentric system he set the rest of the Universe, which he envisioned as a great sphere of fixed stars.

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  Observing the Solar System

  The Modern Astronomer's Guide

  • Gerald North(Author)
  • 2012(Publication Date)
  • Cambridge University Press

    (Publisher)

  CHAPTER 1 Earth and sky Almost all of this book is devoted to the practical methods we astron- omers can use to study the great worlds and other celestial bodies in our Solar System we can see across millions of kilometres of space. To help us appreciate those other worlds it is as well to have to hand some basic facts about our own planet. Also there are some aspects of our Solar System we can observe and study without even using a telescope. So, let us begin our explorations right here, with a brief overview of our Earth and the phenomena that we can see and study without any optical aid . . . 1.1 PLANET EARTH The Earth is a rocky globe, 12 800 km in diameter, orbiting the Sun at a mean distance of 150 million km and taking one year to complete one orbit. The Earth is not quite a perfect sphere but is rather an oblate spheroid, its polar diameter being 43 km less than its equatorial diameter. The difference is caused by the forces arising from the daily (technically diurnal) rotation of the planet on its axis. The Earth is but one of eight major planets that orbit the Sun and they all rely on the Sun as a provider of light and heat. All the planets go round the Sun in the same direction and all keep close to the same plane as they orbit. The mean orbital radii of the major planets and their orbital periods are shown in Figure 1.1. The orbital period of a planet is referred to as its sidereal period. Hence the sidereal period of the Earth is one year. The mass of the Earth is 6 million million million million kg. In scientific notation this is written as 6  10 24 kg. Dividing the Earth’s mass by its volume gives it a mean density of 5515 kg/m 3 . The rocks near the surface of the Earth have measured densities of around 2500 kg/m 3 1

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  Living with Earth

  An Introduction to Environmental Geology

  • Travis Hudson(Author)
  • 2016(Publication Date)
  • Routledge

    (Publisher)

  FIGURE 2-1 Earth Systems

  In this photograph, you can see all four major systems of planet Earth: the solid geosphere; the atmosphere that surrounds us; the water of the hydrosphere; and the diverse life of the biosphere. Together, these make up a single larger system, much as the human body consists of a series of integrated systems, such as the skeletal, muscular, and cardiovascular systems (inset).

  CHAPTER 2

  EARTH SYSTEMS

  You should be very familiar with at least one system—your body. Do you know what kind of system it is? Energy comes in when you eat food, and energy goes out when you pick up the trash, push the lawn mower, or shoot a basketball. Matter is transferred in and out, too—when you breathe in oxygen from the air, eat food, and flush your body’s waste down the toilet. This makes the body an open system, as both matter and energy are transferred in and out. In fact, our bodies are both open and dynamic (changing) systems.

  Scientists have found it helpful to subdivide the human body into parts that are also systems. On the scale of the entire human body, we can define a number of systems, including the muscular, respiratory, skeletal, and digestive systems. Systems in the human body interact. If the muscular system uses oxygen to perform a strenuous activity, then the respiratory system breathes harder. If the circulatory system gets dehydrated, then the nervous system tells us we are thirsty. We can’t realy understand how the human body works without understanding its systems and how they interact. It’s the same thing with Earth and its systems.

  Let’s compare the human body and Earth systems, starting at the scale of the entire human body and the entire Earth. Both systems transfer energy in and out. We just saw that the human body is an open system in terms of energy. Earth receives energy from the Sun and loses energy as it cools very slowly. The body takes in and loses matter. Does Earth receive and lose matter, too? In a way, it does. Tiny amounts of the atmosphere are lost to space, and small partides from space (called meteoroids when they strike the atmosphere and meteorites if they reach the surface) bombard Earth every day. However, even if a large asteroid that is capable of making a big impact on the surface heads Earth’s way, the amount of matter that Earth gains or loses is very small compared to its overall size. |Observation of meteoroid impacts by space-based sensors*

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  Available until 27 Jan |Learn more

  The Green Marble

  Earth System Science and Global Sustainability

  • David Turner(Author)
  • 2018(Publication Date)
  • Columbia University Press

    (Publisher)

  On the cover of Time magazine, Planet Earth was depicted with a thermometer sticking out of it, and the temperature rising into the red zone. Congress was not ready to start limiting carbon emissions, but legislators took heed of scientists’ warnings and made big commitments to more research, notably by funding an array of NASA’s Earth Observing System satellites. Earth system science subsequently emerged as a new scientific discipline that aimed to “capture all processes in nature and human societies as one interlinked system” (Lovbrand, Stripple, and Wiman, 2009, p. 12) at the global scale (Schellnhuber, 1999). Over the past 25 years, a burst of Earth system science research performed all over the planet has led in several directions, some of which point toward an ominous end (Clark et al., 2004). One of the core specialized fields in Earth system science is paleoclimate research. Through examination of the paleorecord (e.g., as found in ice cores and marine sediment cores), we have gained a clearer understanding of the role of greenhouse gases in Earth’s climate over geological time scales (see chapter 2). There is no question that these gases have been dominant players in the dramatic swings in climate that have occurred in Earth’s history. The associated environmental changes have had major consequences for life on Earth and are often drivers of extinction events. Examination of the paleorecord has also made it clear that the biosphere is an active influence on the atmospheric composition (see chapter 3). A key question for the purposes of our collective future is the degree to which the biosphere dampens or amplifies directional changes in the climate system

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