Earth
Overview
Earth is the third planet from the Sun in the Solar System and the only known celestial body in the universe where life exists. It is a terrestrial planet, with approximately 71% of its surface covered by liquid water, earning it the nickname 'Blue Planet'. It possesses conditions suitable for life, including an atmosphere, water, and a magnetic field, and is home to millions of species, including humans.
Main Content
Formation and Structure of Earth
Earth formed about 4.54 billion years ago from the gravitational aggregation of material in the solar nebula. Initially a hot planet covered in lava, its surface cooled over time to form the crust. Earth's internal structure is broadly divided into the crust, mantle, outer core, and inner core. The crust is the thinnest layer, composed of continental crust and oceanic crust. The mantle lies beneath the crust and is divided into the lithosphere and asthenosphere. The outer core consists of liquid iron and nickel and plays a crucial role in generating Earth's magnetic field. The inner core is solid, located at Earth's center, with temperatures reaching about 5,500°C, similar to the surface of the Sun.
Atmosphere and Climate
Earth's atmosphere is composed of nitrogen (about 78%), oxygen (about 21%), argon (about 0.9%), carbon dioxide (about 0.04%), and other gases. The atmosphere supplies oxygen necessary for life, blocks harmful ultraviolet radiation from the Sun, and maintains Earth's average temperature at about 15°C through the greenhouse effect. Earth's climate is determined by various factors such as latitude, altitude, ocean currents, and atmospheric circulation. Tropical climates occur near the equator, polar climates at the poles, and temperate climates in mid-latitudes. Recently, increased greenhouse gas emissions from human activities have accelerated global warming, leading to climate change, sea level rise, and an increase in extreme weather events.
Earth's Rotation and Revolution
Earth rotates on its axis once approximately every 24 hours, causing day and night. The axis is tilted at about 23.5 degrees, resulting in seasonal changes. Earth revolves around the Sun once every approximately 365.25 days, defining a year. Its orbit is elliptical but nearly circular. Earth's rotation and revolution significantly influence the life rhythms of organisms and climate patterns.
Ecosystems and Biodiversity
Earth is broadly divided into terrestrial and marine ecosystems, each forming complex networks where diverse species interact. Terrestrial ecosystems include tropical rainforests, deserts, grasslands, taiga, and tundra, while marine ecosystems include coastal areas, deep seas, and coral reefs. It is estimated that about 8.7 million species exist on Earth, of which only about 1.2 million have been discovered and named by humans. Biodiversity plays a crucial role in ecosystem stability and resilience, but it is rapidly declining due to habitat destruction, climate change, and pollution.
Earth's Resources and Environmental Issues
Earth provides various resources necessary for human survival and development, including water, soil, minerals, fossil fuels, and renewable energy. However, indiscriminate resource consumption and environmental pollution have caused serious problems. Air pollution, water pollution, soil contamination, deforestation, biodiversity loss, and climate change have emerged as global environmental crises. In particular, increased carbon dioxide emissions from fossil fuel use since the Industrial Revolution are identified as a major cause of global warming.
Latest Trends
As of 2024 and 2025, major trends related to Earth's environment are as follows. First, international efforts to address climate change are intensifying. Following the Paris Agreement, countries are setting carbon neutrality goals and accelerating the transition to renewable energy. In 2024, global renewable energy generation capacity reached an all-time high, led by solar and wind power. Second, extreme weather events due to global warming are becoming more frequent. 2024 saw record-breaking heatwaves, wildfires, floods, and droughts worldwide, with scientists warning that these phenomena are closely linked to climate change. Third, advancements in Earth observation technology are making environmental monitoring more precise. Space agencies like NASA and ESA are using high-resolution satellites to track Earth's changes in real time, contributing to improved accuracy of climate model predictions. Fourth, international cooperation for biodiversity conservation is expanding. At the 2024 UN Biodiversity Conference, the '30x30' goal of designating 30% of land and ocean as protected areas by 2030 was reaffirmed. Fifth, circular economy models are gaining attention to address Earth's resource depletion issues. Recycling technologies, development of eco-friendly materials, and resource efficiency improvements are emerging as key research areas.
Related Topics
- [[Solar System]]
- [[Climate Change]]
- [[Ecosystem]]
- [[Global Warming]]
- [[Environmental Protection]]
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