Earth Science

Earth science is science related to the study of our planet Earth. Earth is the only known life bearing planet. Therefore the study of earth can be considered as a special case in planetary science. Both reductionists and holistic approaches are available related to the study of earth. Earth science includes the study of atmosphere, hydrosphere, oceans, biosphere and solid earth. Various tools from mathematics, physics, chemistry, biology and chronology are used by Earth scientists. They make a thorough study about the working of Earth systems and how it evolved to its current state. The major fields of Earth science are classified into subdivisions like geology, geophysics, geodesy, soil science, ocenology, hydrology, glaciology, atmospheric sciences and meteorology. The study of earth’s crust is known as geology. Mineralogy and petrology, geochemistry, geomorphology, engineering geology and sedimentology are the major sub disciplines. The study of shape of earth and its gravitational and magnetic field is covered by geophysics and geodesy. The study about earth’s cryosphere is known as glaciology. The study about gaseous part of Earth is known as atmospheric science. The major sub disciplines are meteorology, climatology, atmospheric chemistry and atmospheric physics.

Interior of Earth

Geological phenomena like plate tectonics, mountain ranges, volcanoes and earthquakes can be explained with the help of energy transformations happening in Earth’s crust. Mantle lies beneath the crust. The mantle is not in solid state and consists of magma. Beneath mantle lies the core. Magma is a mixture of molten rock, volatiles and solids. The process of movement of earth’s lithospheric plates is known as plate tectonics. A new earth crust is created by the movement of lava underneath the lithosphere and the process is known as spreading ridges. The crust is pushed underground through a process called subduction. The inner core of earth contains soft iron and it is surrounded by semi liquid materials of outer core, which moves in continuous current around inner core. So the earth is considered as an electromagnet.

Earth’s atmosphere

Earth’s atmosphere consists of 78.0 % of nitrogen, 20.9 % oxygen and 0.92 % of Argon. The five atmospheric levels are troposphere, stratosphere, mesosphere, thermosphere and exosphere. Water vapor and carbon dioxide present in the earth’s atmosphere allow the planet to hold the energy released by sun through a phenomenon called greenhouse effect. This makes the earth’s surface warm and this is the reason behind availability of water sources in earth. Atmosphere protects the earth from the harmful cosmic rays of sun.

Questions:

• Define earth science?
• What is meant by geophysics?