{"id":378,"date":"2022-02-11T20:12:11","date_gmt":"2022-02-11T20:12:11","guid":{"rendered":"https:\/\/pressbooks.ccconline.org\/astronomy\/?post_type=chapter&p=378"},"modified":"2022-04-28T20:33:27","modified_gmt":"2022-04-28T20:33:27","slug":"summary-6","status":"publish","type":"chapter","link":"https:\/\/pressbooks.ccconline.org\/astronomy\/chapter\/summary-6\/","title":{"raw":"Summary","rendered":"Summary"},"content":{"raw":"
\r\n

8.1<\/span>\u00a0<\/span>The Global Perspective<\/span><\/h3>\r\n

Earth is the prototype terrestrial planet. Its interior composition and structure are probed using seismic waves. Such studies reveal that Earth has a metal core and a silicate mantle. The outer layer, or crust, consists primarily of oceanic basalt and continental granite. A global magnetic field, generated in the core, produces Earth\u2019s magnetosphere, which can trap charged atomic particles.<\/p>\r\n\r\n<\/section>

\r\n

8.2<\/span>\u00a0<\/span>Earth\u2019s Crust<\/span><\/h3>\r\n

Terrestrial rocks can be classified as igneous, sedimentary, or metamorphic. A fourth type, primitive rock, is not found on Earth. Our planet\u2019s geology is dominated by plate tectonics, in which crustal plates move slowly in response to mantle convection. The surface expression of plate tectonics includes continental drift, recycling of the ocean floor, mountain building, rift zones, subduction zones, faults, earthquakes, and volcanic eruptions of lava from the interior.<\/p>\r\n\r\n<\/section>

\r\n

8.3<\/span>\u00a0<\/span>Earth\u2019s Atmosphere<\/span><\/h3>\r\n

The atmosphere has a surface pressure of 1 bar and is composed primarily of [latex]{{\\rm{N}}_2}[\/latex]\u00a0and [latex]{{\\rm{O}}_2}[\/latex], plus such important trace gases as [latex]{{\\rm{H}}_2}{\\rm{O}}[\/latex], [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex], and [latex]{{\\rm{O}}_3}[\/latex]. Its structure consists of the troposphere, stratosphere, mesosphere, and ionosphere. Changing the composition of the atmosphere also influences the temperature. Atmospheric circulation (weather) is driven by seasonally changing deposition of sunlight. Many longer term climate variations, such as the ice ages, are related to changes in the planet\u2019s orbit and axial tilt.<\/p>\r\n\r\n<\/section>

\r\n

8.4<\/span>\u00a0<\/span>Life, Chemical Evolution, and Climate Change<\/span><\/h3>\r\n

Life originated on Earth at a time when the atmosphere lacked [latex]{{\\rm{O}}_2}[\/latex]\u00a0and consisted mostly of [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex]. Later, photosynthesis gave rise to free oxygen and ozone. Modern genomic analysis lets us see how the wide diversity of species on the planet are related to each other. [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex]\u00a0and methane in the atmosphere heat the surface through the greenhouse effect. Increasing amounts of atmospheric [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex]\u00a0from burning of fossils fuels and release of frozen methane are causing the global warming of our planet.<\/p>\r\n\r\n<\/section>

\r\n

8.5<\/span>\u00a0<\/span>Cosmic Influences on the Evolution of Earth<\/span><\/h3>\r\n

Earth, like the Moon and other planets, has been influenced by the impacts of cosmic debris, including such recent examples as Meteor Crater and the Tunguska explosion. Larger past impacts are implicated in some mass extinctions, including the large impact 65 million years ago at the end of the Cretaceous period that wiped out the dinosaurs and many other species. Today, astronomers are working to predict the next impact in advance, while other scientists are coming to grips with the effect of impacts on the evolution and diversity of life on Earth.<\/p>\r\n\r\n<\/section>\r\n

This book was adapted from the following: Fraknoi, A., Morrison, D., & Wolff, S. C. (2016). Summary. In Astronomy<\/i>. OpenStax. https:\/\/openstax.org\/books\/astronomy\/pages\/8-summary under a Creative Commons Attribution License 4.0<\/a><\/div>\r\n
Access the entire book for free at https:\/\/openstax.org\/books\/astronomy\/pages\/1-introduction<\/a><\/div>","rendered":"
\n

8.1<\/span>\u00a0<\/span>The Global Perspective<\/span><\/h3>\n

Earth is the prototype terrestrial planet. Its interior composition and structure are probed using seismic waves. Such studies reveal that Earth has a metal core and a silicate mantle. The outer layer, or crust, consists primarily of oceanic basalt and continental granite. A global magnetic field, generated in the core, produces Earth\u2019s magnetosphere, which can trap charged atomic particles.<\/p>\n<\/section>\n

\n

8.2<\/span>\u00a0<\/span>Earth\u2019s Crust<\/span><\/h3>\n

Terrestrial rocks can be classified as igneous, sedimentary, or metamorphic. A fourth type, primitive rock, is not found on Earth. Our planet\u2019s geology is dominated by plate tectonics, in which crustal plates move slowly in response to mantle convection. The surface expression of plate tectonics includes continental drift, recycling of the ocean floor, mountain building, rift zones, subduction zones, faults, earthquakes, and volcanic eruptions of lava from the interior.<\/p>\n<\/section>\n

\n

8.3<\/span>\u00a0<\/span>Earth\u2019s Atmosphere<\/span><\/h3>\n

The atmosphere has a surface pressure of 1 bar and is composed primarily of [latex]{{\\rm{N}}_2}[\/latex]\u00a0and [latex]{{\\rm{O}}_2}[\/latex], plus such important trace gases as [latex]{{\\rm{H}}_2}{\\rm{O}}[\/latex], [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex], and [latex]{{\\rm{O}}_3}[\/latex]. Its structure consists of the troposphere, stratosphere, mesosphere, and ionosphere. Changing the composition of the atmosphere also influences the temperature. Atmospheric circulation (weather) is driven by seasonally changing deposition of sunlight. Many longer term climate variations, such as the ice ages, are related to changes in the planet\u2019s orbit and axial tilt.<\/p>\n<\/section>\n

\n

8.4<\/span>\u00a0<\/span>Life, Chemical Evolution, and Climate Change<\/span><\/h3>\n

Life originated on Earth at a time when the atmosphere lacked [latex]{{\\rm{O}}_2}[\/latex]\u00a0and consisted mostly of [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex]. Later, photosynthesis gave rise to free oxygen and ozone. Modern genomic analysis lets us see how the wide diversity of species on the planet are related to each other. [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex]\u00a0and methane in the atmosphere heat the surface through the greenhouse effect. Increasing amounts of atmospheric [latex]{\\rm{C}}{{\\rm{O}}_2}[\/latex]\u00a0from burning of fossils fuels and release of frozen methane are causing the global warming of our planet.<\/p>\n<\/section>\n

\n

8.5<\/span>\u00a0<\/span>Cosmic Influences on the Evolution of Earth<\/span><\/h3>\n

Earth, like the Moon and other planets, has been influenced by the impacts of cosmic debris, including such recent examples as Meteor Crater and the Tunguska explosion. Larger past impacts are implicated in some mass extinctions, including the large impact 65 million years ago at the end of the Cretaceous period that wiped out the dinosaurs and many other species. Today, astronomers are working to predict the next impact in advance, while other scientists are coming to grips with the effect of impacts on the evolution and diversity of life on Earth.<\/p>\n<\/section>\n

This book was adapted from the following: Fraknoi, A., Morrison, D., & Wolff, S. C. (2016). Summary. In Astronomy<\/i>. OpenStax. https:\/\/openstax.org\/books\/astronomy\/pages\/8-summary under a Creative Commons Attribution License 4.0<\/a><\/div>\n
Access the entire book for free at https:\/\/openstax.org\/books\/astronomy\/pages\/1-introduction<\/a><\/div>\n","protected":false},"author":33,"menu_order":12,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[48],"contributor":[],"license":[],"class_list":["post-378","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":361,"_links":{"self":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/chapters\/378","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/users\/33"}],"version-history":[{"count":5,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/chapters\/378\/revisions"}],"predecessor-version":[{"id":889,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/chapters\/378\/revisions\/889"}],"part":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/parts\/361"}],"metadata":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/chapters\/378\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/media?parent=378"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/pressbooks\/v2\/chapter-type?post=378"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/contributor?post=378"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/astronomy\/wp-json\/wp\/v2\/license?post=378"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}